How To Hook Up A 4 Channel Amp To Front And Rear Speakers

How to hook up 4 channel amp to front and rear speakers

Adding a 4 channel amp is a great idea. I’ve enjoyed powerful, crystal-clear sound in my vehicles for years using my own 4 channel amps.

But how do you hook them up?

In this guide I’ll show you how to hook up a 4 channel amp to front and rear speakers. After installing hundreds of amps in vehicles just like yours I’ll share with you the fundamental tips you need for great results.

And hey – don’t worry…in most cases you can do it yourself and get professional results on a budget!

Contents

Infographic – How to hook up a 4 channel amp (tips and general guide)

Hook up amp 4 channel amp front rear speakers infographic diagram

Basics first

If you’re reading this there’s a good chance you’re not familiar with installing an amp, connecting wiring, and other details related to hooking up a 4 channel amp in a vehicle.

Not everyone has installed car stereo equipment before so I’m going to be as thorough as possible and avoid making any assumptions about how much you know.

What is a 4 channel amp?

Holding Alpine MRV-F300 amp in my hand

Today’s 4 channel amps offer newer technology, better sound, and more compact size than in the old days. An excellent example is the Alpine MRV-F300 50W x 4 model. It uses Class D technology to run extremely cool and yet it’s small enough to fit under a car or truck seat. Very nice!

What a 4 channel car amplifier is may seem obvious at first but there’s a bit more to know Additionally, there are some interesting (and good) ways they differ from 2-channel amps.

In fact, there are actually a few benefits you’ll get using one 4 channel amp instead of 2 stereo ones to power your front and rear speakers.

A 4 channel amplifier is a stereo amplifier with 2 more channels built in to boost (amplify) weak input signals to a higher voltage signal. This drives speaker voice coils to move the speaker cone and produce sound.

4 channel amplifiers add more channels into a more compact and efficient design than separate amplifiers would have.

Additionally, they offer more flexibility, as most can be configured for “bridged” operation which can give more power when you don’t need all 4 channels.

What is “bridging” an amp?

Bridged mode capability is a special design feature in which a “push-pull” set up is created: one channel (normally used for the left speaker) produces a signal that’s the opposite of the second channel (normally used for the right speaker).

This causes the speaker to receive a voltage audio waveform that is the difference between the two channels – resulting in more available power to speakers.

Essentially, bridged mode is a flexible way to get more power if you’re not driving 4 speakers. It means 2 channels are sharing the workload of one speaker between them and therefore and drive it with more power.

2 channel vs 4 channel amp diagram

2 channel vs 4 channel amp diagram

A 4 channel car amp is basically an expanded version of a 2-channel amp. However, because they’re built together and not 2 separate 2-channel amps, they’re more compact. This saves installation space and makes it easier too. Additionally, most can be bridged to use 2 channels (or 3, depending on your needs) so you’re not restricted to using them with only 4 speakers.

The benefits of using an amp to drive speakers

Whether you have a factory stereo or a great aftermarket (non-factory) one, adding an amplifier is one of the best decisions you can make.

In-dash stereos are very limited in how much power they can produce. They can’t drive speakers with the same clarity and low distortion as a good amplifier can.

The maximum volume you’ll be able to get from your speakers will be pretty low, too.

There’s simply no way around it – most in-dash stereos are limited to about 15W-18W RMS of power for each speaker channel. That’s because they’re running directly from the +12V supply. Amplifiers are unique in that they take the +12V electrical supply and boost it to a higher voltage.

When a signal is boosted and sent out to your car’s speakers the voltage is much higher and the speaker can receive much more power.

That’s why tiny amplifiers are rarely worth bothering with – if there’s no special power supply inside, it’s simply not capable of producing much power.

Getting great sound

Powering speakers from an amp makes a big difference, and I’ve enjoyed excellent sound for years this way.

When an amplifier drives your vehicle’s speakers it’s often not even pushed to its limits. The sound produced at the speaker has lower distortion, doesn’t “bottom out” when heavy bass is played, and you can get a lot more volume, too!

Additionally, using an amplifier with built-in high-pass crossovers means you can block out lower-end bass that causes your speakers to distort and attempt to play music tones they’re not suited for.

The result is cleaner sound, less distortion, and great volume – you can crank your music even higher!

Just imagine driving down the road with the windows open and finally being able to blast the music you love. I’m confident you’ll love it as much as I do.

Things to know before you start

Clip art image of a face thinking - Things to know content image

It only takes a few minutes to make a list of the parts, wire, tools, and other bits and pieces you’ll need. Planning ahead can mean the difference between getting your system going without major problems or having a frustrating time – or complete failure! I always get organized and get my items together before I start a job.

Planning ahead is very important. You don’t want to run out of wire or discover you don’t have the rights parts, for example. That will mean you can’t finish your project.

It’s even worse when you have to drive around town searching for items or you’re not able to do anything after the stores close. Believe me, I’ve been there, and it’s terrible!

Notes about wire, tools, and a few other things

When it comes to installations, always plan to have more, rather than not enough, wire. This goes for speaker wire as well as RCA cables.

The amplifier kits I recommend have the right length for your amp installation, but speaker wire & RCA cables are another matter in this case.

What length and size speaker wire do I need?

wire of 16 ga speaker wire

There’s no need to spend an excessive amount of money on speaker wire. 18 gauge is enough for many installations, but 16 gauge is a great choice too if the price is right. A great example is this AmazonBasics 100 foot roll. I recommend a 100 foot roll for many installations with a 4 channel amp (see why below).

Here’s an estimate of the worst-case scenario for the length of speaker wire required. I’ll use the example of installing an amp using speaker-level inputs, with the following typical installation:

  • Amp is located in the trunk
  • Speaker level signal connections near the radio (center console)

Let’s use roughly a 15′ length of distance from the radio to the amp. That’s a good estimate in my experience.

So we have:

  • Wire from the radio to amp (signal wire): 4 channels x 15′ = 60 feet
  • Wire from the amp to speaker wiring near radio: 4 channels x 15′ = 60 feet

Total estimated wire required: 120 feet.

That means you need 2 100 ft rolls of wire. Or at the least, 1 100 ft roll and 1 50 ft roll. If you’re planning to use a line-level adapter, expect to pick up a 100′ roll.

If your installation is using RCA jacks, expect a 100 ft roll also (4 channels x 15′ length estimate for the speaker wire from the amp).

What about RCA cables?

KNU Conceptz KCA-K4 4 gauge amp wiring kit RCA cables imageIf you’re installing a 4 channel amplifier and using RCA cable connections, you’ll need to buy a 2nd pair along with your amp wiring kit, as most only include a 2-channel cable.

For most installations, I recommend 18′ length cables. That’s usually long enough for most vehicles and you should usually have enough length to hide the cables inside the interior and under the rear seat, etc.

There’s no reason to spend an excessive amount of money. Just pick up some good quality, well-made cables. Even a pair like these value-priced ones will be fine in most cases.

Tools you’ll need.

Image showing example crimp tool and crimp connectorsCrimp tools are great for installing your amp and speaker wiring with professional results. If you’re doing your own installation, you can get by with an inexpensive tool like this Pros'Kit crimp tool. Crimp connectors are sold separately in many automotive parts stores or general stores and are very affordable.

I recommend a few tools. If you shop carefully, you can avoid getting ripped off on tool prices. When connecting speaker wiring to factory wiring, it’s easier to use crimp connectors than solder.

Never simply twist the wire together and wrap it in electrical tape. Always use a reliable connection.

During warm weather, electrical tape adhesive can fail and the tape can come off of the wire. This exposes it to possible short circuits and potential damage to your radio or amp.

If you have access to a cordless drill, that’s fantastic! They’re great for drilling holes in the vehicle’s metal for mounting your amplifier or connecting the ground wire to bare metal.

I also recommend the following:

  • Wire cutters (some crimp tools have this built-in)
  • Roll of quality electrical tape
  • Wire ties (“zip ties”), 6″ length, bag of 100
  • A digital test meter for voltage measurement

Etekcity MSR-R500 digital test meter example

A test meter is often incredibly helpful when installing an amplifier. However, you don’t need to spend much money! A basic but good budget model like this one at Amazon will work great.

I recommend getting an affordable but good digital test meter to find a switched +12V wire for getting a remote-on signal to the amp.

They’re also extremely helpful when troubleshooting power problems when something isn’t working.

Get your installation shopping list together

Image of a paper checklist being prepared with a marker

Here’s a general but pretty accurate list of what you’ll need for connecting a 4 channel amp to front and rear speakers.

Installation types 1 or 2: Factory radio or no RCA connections

  1. 4 channel amplifier with speaker level inputs or amp and line-level adapter
  2. 120 feet or more speaker wire, 18 gauge or larger
  3. Amp wiring kit
  4. Crimp tool and butt (wire crimp) connectors (25 or more at least)
  5. Cutting pliers
  6. Electrical tape
  7. Wire ties, 6″, bag of 100
  8. Test meter

Installation type 3: RCA connections

  1. 4 channel amplifier with speaker level inputs or amp and line-level adapter
  2. 100 feet roll speaker wire, 18 gauge or larger
  3. Amp wiring kit
  4. Additional RCA cables, 18′ minimum
  5. Crimp tool and butt (wire crimp) connectors (25 or more at least)
  6. Cutting pliers
  7. Electrical tape
  8. Wire ties, 6″, bag of 100
  9. Test meter

Be sure to plan well and estimate the amount of speaker wire you’ll need. For the amp installation itself, I strongly recommend using a pre-made amp wiring kit like you’ll find here in my amp kit buyer’s guide.

You’ll also need to get a 2nd pair of RCA cables. I recommend 18 ft length or more. Don’t spend too much money, but do get decent quality ones.

How to get a signal to your amp

Image of an aftermarket car stereo outputs labeled

Image of an aftermarket (non-factory) stereo showing the RCA jacks and speaker output wiring. Either one can be used for getting a signal to an amp, but RCA jacks offer a better option. They’re normally lower distortion and allow using plug-in RCA cables. If those aren’t available, either an amp with speaker-level inputs or a line level (speaker level) adapter can be used.

In order to install a 4 channel amp and drive all 4 speakers, in many cases, the biggest obstacle is getting a signal to the amp. Once that’s done, the rest is usually a standard amp installation.

There are 3 basic ways to get a signal to your 4 channel amplifier:

  1. Connect speaker outputs to your amp’s speaker level inputs
  2. Connect a line-level adapter to the radio then use RCA cables to the amp
  3. Connect your radio to the amp using RCA cables directly
NOTE: I won’t be covering factory sound systems that are “premium” and have a factory amplifier. Those such as Bose, JBL, and Mark Levinson, often found in luxury vehicles or special-edition models, are much more complex and harder to deal with.

In that case, my advice is to speak with a good installation shop first and do your research.

If you feel that factory amplified systems should be here as well, send me a message or comment and let me know

In a few cases, adapters are available to connect an amp to a factory amplified system’s audio wiring, but it’s often difficult or there are obstacles you won’t find until you get started.

One of the reasons why is that factory amplified systems often have non-standard wiring connections for the audio path and are prone to bad noise problems if you connect an amplifier without the proper adapter or wiring.

Which type of connection do I need?

If you have a radio with RCA jacks, skip on down to the next section.

However, if you have a stereo with no RCA jacks (which is always the case for factory-installed stereos) you’ll have to buy one of the following:

  • A “line level” converter
  • An amplifier with speaker-level (“high level”) inputs

1. Line level converters

PAC LP7-4 4 channel line level converter

Line-level converters like this PAC LP7-4 4-channel model are designed to take speaker-outputs from a stereo with no RCA jacks and adapt them to RCA jacks. Using this, you can run RCA cables to your amplifier.

Line level converters are designed to allow connecting to an amplifier’s RCA inputs by converting speaker outputs from a stereo to a low-level signal an amp can use.

It’s very important to buy a quality, well-designed line-level adapter to avoid noise, poor sound quality, and other problems. Don’t get the cheapest – instead, get a name brand model you can rely on (like the one above).

2. Speaker level inputs

Car amplifier speaker level input example
Amplifiers with high-level (speaker-level) inputs like this one allow connecting to speaker wiring for a signal source. This avoids having to buy a separate adapter.

Speaker level inputs are common on many 4 channel amplifiers. These amps contain electronics that scale down speaker wiring signals to a lower signal safe for the amplifier’s input circuitry.

They’re simple to connect: normally it’s just a matter of connecting both positive (+) and negative (-) wiring for each speaker channel on a small wiring harness included. This then plugs into the speaker level input connector.

4 channel amp speaker level harness example

A typical speaker-level input harness for a 4 channel amp. The wires are color-coded to make installation easier. White = left front, gray = right front, green = left rear, and purple = right rear.

While it can save money (you won’t need a line-level adapter in this case) I often recommend that people consider buying a line-level converter anyway.

This allows an easier upgrade for your stereo later, which is very common for people to do. Using the line-level converter now will allow you to run RCA cables to your 4 channel amp to be used later if you buy a better stereo (which will include RCA jacks, almost always).

3. RCA jack (line-level) connections

RCA jacks offer a clean, lower-noise connection than speaker-level adapters do, but honestly, it’s not noticeable to the average person. RCA cables (line-level connections) are the preferred way to connect a signal to your amp if you have that option.

RCA jacks on the rear of a Pioneer head unit. This is the ideal way to connect your amplifier’s signal inputs, if available. For a 4 channel amplifier, you’ll need 2 stereo RCA cables to do so. White represents the left channel white red represents the right. These are standard colors for audio outputs for both car and home stereo.

If your stereo has RCA jacks, then congratulations. Things just got a bit easier – and potentially better sounding, too!

You’ll need 2 stereo RCA male-to-male cables (4 audio channels total) to run from the radio to your 4 channel amp. That’s 4 signal channels: left & right front and left & right rear.

4 channel amp signal connection diagram

Here’s a helpful diagram showing the most common connections you’ll need to make one of the 3 most common cases I mentioned earlier:

  1. Connecting to your amp’s speaker level inputs
  2. Using a line-level converter
  3. Connecting your amp to the radio’s RCA jacks

4 channel amp signal connection diagram
You can also click here to view the .pdf document for print or download.

Connecting and running signal wiring

Speaker-level connections

As mentioned above and as shown in the diagrams, if you’re using speaker-level outputs to get a signal from the radio, you’ll need to connect wire. Ideally, you’ll do so near close to the radio, then run the wire together as a bundle.

You can bundle speaker wire together with wire ties to keep it neat and make the installation easier.

Estimate the length of speaker wire you need to reach the amp (or line level converter) for each audio channel. To do so, run a length of wire from the radio to where the amp will be installed, then allow a little extra and enough length to run around curves and interior parts.

Cut 7 more lengths of wire, for a total of 8:

  • 4 channels (4 pairs of wire) going to the amp’s speaker level inputs
  • 4 channels from the amp to the radio’s factory speaker wiring

Image of car stereo wires crimped

I recommend connecting to speaker-level outputs using crimp connectors and a crimp tool for a reliable, solid connection. Blue connectors are normally the right size for 18-16 gauge wire.

Factory stereo color codes

If you have a factory stereo, you’ll need to find the wiring colors for the speaker wiring.

A great resource for that is The12Volt.com, where you’ll find wiring diagrams for your vehicle and color codes listed.

Making connections

Image of factory stereo wiring harness

After removing the radio you’ll find connectors like this for the factory stereo wiring harness. You’ll need to separate the speaker wires, cut them, and attach wiring to run to the amp.

Remove the radio and disconnect the factory wiring plugs or aftermarket radio’s wiring harness.

Cut the speaker wires, leaving enough length to move the wire and to have enough length to connect to the wire freely.

Strip a small part on both the stereo’s speaker wire and your amp speaker wiring. If using a line-level adapter, connect to the stereo’s speaker output side. Then connect the 4 pairs of wire to the speaker wiring in the harness.

Insert the stripped wire (about 1/4″ of bare wire) into the connectors and crimp them carefully using a crimp tool if you have one. Alternately, you can twist together wire, solder it, and carefully wrap it with electrical tape or use heat shrink tubing for insulation.

If using speaker level inputs on your amp, also connect 4 pairs of wire to the output of the stereo.

Wire bundle with zip ties example

To make a neater, more professional installation, bundle the speaker wiring similar to this using wire (“zip”) ties. I recommend using 6″ ties which often are sold in packs of 100.

Once all wiring is connected, bundle it up using wire ties or, optionally, a little bit of electrical tape wrapped around. In both cases spacing out wire ties or tape about every 1″ or 1.5″ along the length of the wire works well.

Connecting RCA cables

Example of connecting RCA cables to rear of a car stereo

Connecting RCA cables to an aftermarket (non-original) stereo for running to an amplifier.

If you’re using a line-level converter or have a stereo with RCA jacks, connect all 4 cables plugs to the front and rear outputs.

RCA cables are sometimes marked with left and right symbols (“L” and “R”). In some cases, white, clear, or some lighter color can be used to represent the left channel.

Connect the cables consistently so you’ll be able to recognize which one is which. If the front and rear RCA cables are the same, you might want to mark front and rear using some masking tape and a marker or pen.

Connect the remote-on amp wire

Don’t forget the remote wire! Amp wiring kits include a small wire that’s used to connect the amp so that it switches on and off with the accessory position of the ignition switch.

Locate a +12V wire that has power when the ignition is switched to “ACC” or similar but turns off with the key. You may also have good luck finding an existing wire color from vehicle wiring diagrams I mentioned earlier or from a Google search.

I recommend checking the wiring even if you have already located it online, just to be sure.

Before re-installing the radio connect this wire and run it alongside the speaker wiring.

How to connect a 2 ch. car stereo to a 4 channel amp

Diagram showing a 2 channel car stereo connected to a 4 channel amp

You can connect a head unit car stereo with only 2 channels (left and right) to a 4 channel amp easily. Ordinarily, all you need is 2 RCA Y adapter cables. The head unit’s left channel RCA jack should be connected to the left front and left rear amp inputs. Likewise for the right channel. If using speaker level inputs on the amp, use the connections shown above. NOTE: Use only ONE of the two connections above! Never connect both types at the same time! Speaker-level outputs will damage RCA connections.

If your head unit (car stereo) only has 2 RCA jacks or two pairs of speaker outputs, that’s not a problem.

As shown in the above diagram, you can connect 2 channels to a 4 channel amp using either the speaker level inputs wired in parallel or by using simple RCA adapter cables.

RCA y adapter cable image

All you need is a decent pair (a total of 2) female to male RCA “Y” adapters like these low-cost ones from Amazon.

The sound quality will be exactly the same. Today’s amps are designed in such a way that there’s no harm in using a Y adapter to connect the amp. The amplifier will receive exactly the same signal, with the same quality, in the front channels as well as the rear.

The only drawback is there won’t be a front to rear fader control like with head units with 4 channels of outputs.

After connecting the stereo to the amp, you’ll need to adjust the rear gain to set the volume level for the rear speakers as needed for the proper volume depending on the stereo’s signal strength.

Installing the amp

Product image of Belva BAK82 amp wiring kitAn amp wiring kit like this one will make installing your 4 channel amp much easier. A good-quality one like this Belva 8-gauge complete kit includes not just wiring but much more. You’ll also need to pick up a 2nd pair of RCA cables (if using them) and enough speaker wire.

Your amplifier needs a good solid metal connection to ground and you’ll need to run the positive battery wire to the engine compartment. Your amp wiring kit will also include a fuse holder that should be installed near the battery as well (most kits include instructions, by the way).

You’ll also need to connect the amp’s speaker outputs to the wire you ran from the radio.

As it also applies to 4 channels amps, for the amplifier installation you can follow my guides here:

Here’s a basic diagram as well to help:

How to install a 4 channel amp diagram

Setting up your amp

Alpine MRV-F300 4 channel amp end viewOnce installed, you should set up your amp’s gain levels and crossovers for the best sound. In this image, you can see the adjustable crossovers for both front and rear channels. Turn on the high-pass crossovers and adjust to a setting close to 50-60Hz, to allow good bass for music but block low-end bass that distorts.

Once installed, you’ll need to set up your amp’s gain levels and crossovers, if available. Most sold today have that. (See my recommendations at the end for some great models)

Gain control is the amount of signal amplification the amplifier performs. Ideally, with a good input signal, it can be kept low to reduce any hiss or noise that can appear when it’s turned up high.

Here’s a great rule of thumb for how to adjust the gain for this type of system:

  1. Turn down gain controls on the amp
  2. Turn the stereo’s volume to 2/3 of maximum
  3. Slowly raise the gain controls until the volume is enough

When finished you should have enough volume available from the stereo but noise should be minimal. You’ll still need to tweak it a bit if the volume is too high or too low.

Setting the crossover

As I mentioned at the beginning of this guide, using high-pass crossovers will allow more volume with less distortion and will help protect the speakers from heavy bass.

For both front and rear channels turn on the high-pass feature and, if an adjustable dial is available, set it near 50 to 60Hz. Some models don’t offer an adjustable frequency for the cutoff but are likely preset to a good level.

Test and tweak

Once installed, test and tweak your amplifier as needed. A great way to mount your 4 channel amp is by using a board mounted to the car, covered with speaker box carpet or other material.

Play some music you’re very familiar with and adjust things like bass, treble, and the fader as needed. Using music you’re very familiar with (of high quality) means you’ll be able to notice any problems with the sound fairly easily.

If you don’t already have one, you might consider later upgrading to a head unit with built-in equalizer (EQ) functions to help tailor the sound.

Summary and recommended products

Hopefully you’ve found this post useful. Hooking up a 4 channel amp to your front and rear speakers takes some work and time, but it’s a great way to get sound you’ll love.

Considering buying an amplifier? You can find some great 4 channel amps (including the Alpine MRV-F300 pictured here) in my 4 channel amp buyer’s guide.

You’ll also need a good amp wiring kit – I’ve got a good amp kit buyer’s guide here.

If you find anything missing or have suggestions, just leave a comment below or send me a message!

How To Wire A 4 Channel Amp To 4 Speakers And A Sub: A Detailed Guide With Diagrams

Featured image for how to wire a 4 channel amp to 4 speakers and a sub

4 channel amps are great and have a lot of flexibility for the most part. However, they’re intended for use with 4 speakers or 2 speakers and a sub – not both.

However, it is possible to wire a 4 channel amp to 4 speakers and a sub! I’ve put together some really detailed information to help make this as painless (and inexpensive) as possible.

Read on to find out how! There are plenty of detailed diagrams to guide you, too.

Contents

What you need to know first

Clip art image of a face thinking - Things to know content image

Let’s get a few things out of the way before we go any further. To drive 4 speakers and a sub with a single 4-channel amp you’ll have to make a few compromises.

I’ll explain here what I mean:

  • You’ll likely have to give up front-rear fader control ability as you’re giving up 2 channels for the rear speakers to drive a sub (2 front/2 rear).
  • Most but not all car amps today can handle speaker loads down to 2 ohms. If yours doesn’t, you’ll need a work-around I’ll show you. You may need a few extra parts.
  • Driving 4 speakers from 2 channels means the speakers are sharing the amp’s power, so you’ll have less power available to each of those.

That being said, don’t worry too much! You can still enjoy the music you love with a nice-sounding 4 speaker + subwoofer system.

What does the minimum impedance (Ohms) rating mean for an amp?

Image showing the minimum speaker Ohms rating for Rockville RXA-F1 4 channel amp as an example

Image showing a typical 4 channel amplifier’s minimum speaker load (Ohms) rating. Most car amps today have a minimum of 2 ohms per channel in standard (stereo) use and 4 ohms minimum when bridged. Never run an amplifier with a speaker load that’s lower than the rating! Your amp will run hot and possibly become damaged.

Today’s 4 channel (and other) car amplifiers have a minimum speaker load they can handle. The speaker impedance or “Ohms” rating of a speaker (also called the speaker load) is the resistance to the flow of electrical current that the amplifier sees at the speaker terminals.

Amplifiers are designed to handle a minimum speaker load. The rating shown on the amp or in the owner’s manual serves as a warning.

If you connect a speaker load below the amp’s minimum rating it can get hot and even become permanently damaged at some point.

I’ve seen this happen when people try to “get more power” by incorrectly wiring speakers to an amp. Don’t do it! Burning out your amp’s output stages is not a nice surprise.

Minimum speaker loads for wiring a 4 channel amp to 4 speakers and a subwoofer

Diagram showing series and parallel speaker Ohms calculation examples

Diagram showing how a car amplifier’s Ohm rating works with speakers. Speakers are usually connected in series or parallel (well, really, most often in parallel) which affects the total resistance an amp will see. That’s important because amps are designed for a certain minimum speaker load (Ohms rating).

As I mentioned above, most car amps today can handle a 2 ohm load per stereo channel (left & right channels) and 4 ohms minimum when bridged to drive an amplifier (called “mono”).

The real answer, however, is that it depends on your amp’s ratings. Always be sure to check to be sure. To keep it simple, I’ll summarize what will work for almost all systems & amplifiers you’ll come across.

The amp wiring systems I’ll cover here

In this post I’ll cover 3 types of systems as that should cover almost all amps you’ll find:

  1. 4 channel amps with a minimum speaker load of 2 ohms in stereo, 4 ohms bridged (for the subwoofer)
  2. 4 channel amps with a minimum speaker load of 2 ohms in either stereo or bridged
  3. 4 channel amps with a minimum speaker load of 4 ohms

#3 is less common but it’s one you’ll run across. Maybe you’ve got an older amp that’s been sitting around unused. If so, you’ll be glad to know there’s a work-around that I’ve come up with that will let you wire your 4 speakers up without damaging your amp.

4 Channel Amp Wiring Examples

Here are the speaker wiring and speaker (Ohms) loads possible for nearly all amps you’ll run across. I’ll describe 3 main system setups which I’ll cover in detail.

System 1: 2 speakers (parallel wiring) to each front channel = 2 Ohms x 2 + 1 subwoofer wired for 4 Ohms on the rear channels bridged for more power. This is the first and best choice for most modern 4 channel amps.

System 2: 2 speakers in parallel to each front channel = 2 Ohms x 2 + 1 subwoofer wired for 4 or 2 Ohms on the rear channels bridged for more power. 4 channel amps that handle 2 ohms bridged are less common but they are out there.

System 3: 2 speakers on each front channel (parallel wiring) wired with extra parts for 4 ohms per channel + 1 subwoofer wired for 4 ohms minimum. Because these kinds of amps can’t handle a 2 ohm load, it’s a bit harder and needs a different approach.

Testing speaker ohms with a multimeter

Image showing an example of how to test speaker ohms with a multimeter

Shown: An example of how to measure speaker impedance (Ohms) with a multimeter. It’s a great way to know for 100% sure what kind of speakers you’re dealing with to avoid problems with your 4 channel amp.

Car stereo and home speaker speakers are very similar except for the impedance rating they use. A speaker’s impedance value, measured in Ohms, is just the total measurement of electrical resistance the amp will see from the speaker’s voice coil.

Partly due to tradition in the electronics world and partly due to various other electrical reasons car stereos are commonly rated at 4 ohms and home stereo speakers around 8 ohms.

The good thing is that all you really need to know is roughly what the resistance of a speaker is. If you can measure that you can tell what Ohms rating to go by!

How to measure speaker Ohms with a multimeter

Example image showing how to use multimeter probes on a speaker

To measure the Ohms (resistance) of a speaker’s voice coil, hold the meter probes to the speaker terminals, making sure to keep firm contact to bare metal Paint, insulation, dirt, and solder flux can mess up your reading otherwise.

For example, we usually have a label on a speaker telling us if it’s 2 ohms, 4 ohms, and so forth. However, as crazy as it sounds, some speakers don’t!

That’s why it’s excellent to have a multimeter handy – you can find out 100% for sure.

Measuring speaker Ohms with a multimeter
  1. Set the multimeter to the Ohms setting. If the meter has an auto-ranging function you should be fine. Otherwise, set it to the lowest setting like the 10 Ohms or 200 Ohms range, etc.
  2. With the speaker disconnected, touch the speaker terminals with the meter probes. Be sure to touch bare metal on the terminals and make good contact.
  3. Read the measured value. The general range will tell you the Ohms rating of the speaker (Example: 3.6 ohms resistance would mean a 4 ohm speaker)

It’s important to be sure you’re not measuring across substances that can interfere with your measurement.

Things like the following can cause problems (I have seen this happen many times!):

  • Leftover solder flux or solder coating from manufacturing
  • Heavy oxidation
  • Heavy dirt, dusty, or other contaminants that build up over time
  • Paint or other coatings that don’t conduct electricity

If in doubt, you can rub them gently with a bit of sandpaper or even scratch the meter probes against the terminals to make better electrical contact.

Note: If a speaker is “blown” or burned out from abuse or physical damage to the voice coil you’ll never get a reading. That’s because for blown speakers the voice coil no longer has a complete electrical path you can measure.

Multimeters show an open circuit condition as “infinite” Ohms, which just means there’s no reading to be made.

Speakers don’t measure exactly 4 or 8 ohms!

Car and home speakers are rated by their general Ohms (impedance) rating. For example, 2, 4, and 8 ohm speakers are never measure exactly with those Ohm measurements.

That’s because each speaker’s design is a bit different from the next. The resistance you measure from a speaker is due to the voice coil’s resistance thanks to the long wire it’s made of.

Here’s an example chart to help you know what to expect when measuring speakers.

Speaker RatingTypical Measurements
2 Ohms1-1.8 Ohms
4 Ohms3.2-3.6 Ohms
8 Ohms6 Ohms or more
16 Ohms12 Ohms or more

As you can see, you won’t measure exactly 4 ohms for a 4 ohm speaker. It will be in the general range and close to its advertised rating, however.

What is “bridging” an amp? Why is this best for driving a subwoofer?

Diagram showing a 4 channel car amplifier bridged to 2 channels

Shown: Example of a 4-channel amp bridged to 2 channels.

Bridged mode (mono mode) is a built-in amplifier feature in which a “push-pull” set up is created: one channel (normally used for the left speaker) produces a signal that’s the opposite of the second channel (normally used for the right speaker).

When this happens the result is that you’ll get substantially more power with them working together than you would with one channel alone.

Bridged mode is a flexible way to get more power from 2 channels (in this case the rear channels, for example). That’s especially important because subwoofers are big, heavy speakers that need more power than small speakers to produce the bass sound you want.

Diagram – How to wire a 4 channel amp to 4 speakers and a sub

Note: Most standard aftermarket car speakers are 4 ohms each so I’ll use that assumption for my diagram. Always be sure to check your speakers before you wire them to your amp to be sure they’re compatible.

(Or click on the image to enlarge & zoom)

Detailed diagram for how to wire a 4 channel amp to 4 speakers and a subwoofer

Using power resistors for harder installations (4 ohm min. amps)

Image showing examples of higher power resistors (4 ohms) for use with speakers

Shown: High power resistors that can be used with a 4 channel amp when adding more speakers. Using these will allow you to keep the total speaker load (speaker Ohms the amp sees) to a safe level so the amp won’t get damaged. They’re inexpensive and are easy to use.

Power resistors are larger versions of the resistors used in many electronic products. Unlike their smaller siblings, they’re designed to be able to handle a large amount of heat.

Because of this, they’re a great way to deal with more difficult speaker and amp systems. In example #3 I showed you earlier, it’s not possible to use two 4 ohm speakers in parallel with an amp that can’t handle 2 ohm loads.

We can use 1 large resistor for each speaker as a work-around for this.

This workaround won’t be necessary for most modern car amps. However, since a few amps out there can’t handle 2 ohm loads (especially older amps you might have that you’d like to use) I’ve included this just in case.

Diagram showing how to wire speakers with power resistors for 4 ohms total

In the case of a car amplifier that can’t go below 4 ohms per channel, there’s no other way. However, if we add one 4 ohm power resistor in series with each speaker we can use the math to our advantage.

By doing so, we’ll end up with two 8 ohms measurements in parallel which will give us a nice, safe 4 ohms per channel!

However, you’ll want to buy the right kind of resistor. I recommend at least 25 watt (25W) 4 ohm resistors. While you won’t find them in many local stores, the good news is that they’re affordable. I’ve used them many times for speaker problem-solving.

I’ve used some like these over at Amazon.

How to get around the lack of a front/rear fader

As I mentioned at the beginning, if you’re using a 4 channel amp to drive both 4 speakers and a subwoofer, you’re going to have to make compromises. There’s simply no way around it.

The biggest one that comes to mind is losing the front/rear fader control. However, I’ve come up with a sort of solution that helps a bit!

By adding inline resistors to the rear speakers you can drop their volume and it acts as a “fader” already. You can use an L-pad (speaker volume attenuation) site like this one here to calculate resistor values for you.

I’ve already done the work for you, and here’s a great example. If you’re wiring 4 speakers and a subwoofer to a 4 channel amp, by adding 60 ohm resistors to the rear speakers you’ll drop the volume by 24dB (decibels).

The result will be that the sound is “faded” to the front and the rear speakers won’t be too loud.

Image showing to how to create a fader to rear speakers using resistors

Following the example I’ve provided here in the diagram above it’s pretty easy. You’ll need to pick up some 15W-20W (or higher) resistors. I recommend about 60 Ohms as it will give a volume reduction of 24dB.

That should be enough in most cases: Not totally silent in the rear, but most of the volume towards the front speakers.

What crossover settings should I use on my 4 channel amp?

Close up image of a car amp crossover controls

As most modern car amplifiers include very nice optional crossovers, for good sound it’s smart to take advantage of those.

Here are some good recommendations for the 4 main speakers and the subwoofer:

SpeakerCrossover Settings
4 main speakersFlat (crossover off) or 56-60Hz high pass
Subwoofer80Hz low pass

By using a high-pass filter for the 4 main speakers you can crank the volume when you want for more power & sound before distortion happens. When using a subwoofer, it’s really important to block vocals and upper-frequency music from getting to your sub.

The idea is to get “pure” bass sound as that’s what subwoofers are best suited for: Just purely producing great-sounding bass you’ll love.

What if my amp can’t be bridged?

Image with diagram of how to bridge an amplifier

While it’s true that nearly all amps with any “real” power today can be bridged from 2 channels to 1 channel (called “mono”, or bridging) for more power, some can’t. That’s especially the case for some older “old school” amps you might have in your closet but still like to use.

In that case, unfortunately, you’re really limited. Sorry! You have just a few options:

    1. Buy another small amp just for the subwoofer/subwoofers
  1. Run one small subwoofer from each of the rear channels

The problem with option #2 is that subwoofers need a lot more power to drive them well and sound good. There’s just no way around it.

8″ subwoofers are an option or a dual 4 ohm voice coil subwoofer could be used. That way you can safely drive each channel with a 4 ohm load even older amps can handle. These days, though, it’s usually easier just to get a cheap budget amp and avoid the headaches.

How to connect a 2 ch. car stereo to a 4 channel amp

Diagram showing a 2 channel car stereo connected to a 4 channel amp

If your stereo doesn’t have output channels that’s ok! You can still connect a head unit car stereo with only 2 channels (left and right) to a 4 channel amp easily. In most cases, you only need 2 RCA Y adapter cables. The head unit’s left channel RCA jack is connected to the left front and left rear amp inputs. Then the same for the right channels. If using speaker level inputs on the amp, use the connections shown above. NOTE!: Use only ONE of the two connections shown. Never connect both the speaker level and RCA jacks at the same time – speaker level signals can damage your head unit’s RCA outputs.

If you’re wanting to install a 4 channel amp for 4 speakers and a subwoofer but only have 2 stereo channels available, that’s ok.

As shown in my diagram, you can connect 2 channels to a 4 channel amp using either the speaker level inputs wired in parallel or by using RCA “Y” adapter cables.

RCA y adapter cable image

All you need is a decent quality pair (2 total) 1 female to 2 male RCA “Y” adapters like these inexpensive ones from Amazon.

The sound quality will be exactly the same. Modern car amps are designed in a way such that all 4 inputs will get the same signal and there won’t be any problems.

After connecting the stereo to the amp, you’ll need to adjust the gain controls for both the 4 main speakers and the subwoofer output. My advice is to use a high-quality music track you know well already so you can easily tell when music sounds correct.

Additional suggestions & parts you may need

An amp wiring kit like this one will make your life easier! A a great (but affordable) amp wiring kit like this Belva 8-gauge complete kit includes not just the basics but a lot more. You’ll also need to pick up a 2nd pair of RCA cables (if using them) and maybe some extra speaker wire, too.

I can’t stress enough how important it is to be ready to install your 4 channel amp. While there are several ways you can go about it, wasting gas, time, and getting stressed out isn’t worth the headache.

It’s a lot better to start on the right foot and be ready at installation time. My advice is to pick up a good amp wiring kit and the tools you need beforehand.

I’ve also got some great guides ready, too, if you’d like more ideas:

Need advice on finding the right installation wiring? Check out my post with some of the best wiring kits for the money here. You’ll not just save a few dollars but avoid getting ripped off on fake wire gauges.

Comments, questions, or more? Let me know!

I’d love to hear from you and make this post even more helpful. Let me know in the comments below if you have questions or comments.

You can also reach me here via my contact page.

The DIY Car Amp Rack Guide – How To Build Your Own Car Amp Rack In One Day

DIY car amp rack image

Making your own DIY car amp rack may seem like something that’s out of reach. Or maybe you don’t know where to begin and you’re worried you’ll have to pay someone else a lot of money to make one.

Here’s an affordable way to build a do it yourself (DIY) car amp rack in one day.

I still use these same car amp rack plans in not just customer vehicles but my own, too! I love how simple but professional looking they are. It’s pretty cool getting compliments on how great and pro-level it looks.

Now you can build your own car amp rack that looks great and is affordable, too!

Contents

Infographic – Basic amp rack how-to guide

DIY car amp rack infographic image

Getting your tools & supplies ready – what to know first

Clip art image of a face thinking - Things to know content image

Tools you’ll need

You’ll need a number of tools to do the job well:

  • Phillips screwdriver
  • Cordless drill + Phillips bit (not essential but highly recommended) or standard electric drill
  • Pliers – I recommend square-jaw, locking, or other types but needle nose can work, too
  • Scissors for cutting material + utility razor (optional)
  • Staple gun (optional)
  • 1/8″ drill bit suitable for metal
  • Basic tape measure or measuring tape
  • Something to take notes with
  • Permanent marker

As you can see you won’t need many tools. That’s part of the reason this approach works well. I’m hoping to help you carry out this with as little money and hassle as possible.

If you can, borrow any tools you don’t have from others to save money and time.

For many basic items you can get great deals at stores like Harbor Freight Tools, Wal-Mart, or even the Dollar Tree $1 store. If you shop carefully things like pliers can be found for around $2 a pair.

Arrow T50 staple gun with staples

A staple gun can be bought when you go shopping for the materials you need, but it’s completely optional. They can drive strong staples into wood unlike a standard stapler and they’re great for stapling fabric securely. You can pick up a staple gun for close to $15 or so.

Will I need a power saw?

Fortunately, most likely you won’t need a saw. In the sections that follow you’ll need to shop for wood, but if your city has a Home Depot or Lowe’s hardware store, the great news is that they offer free wood cutting when you buy wood! And that’s also that much less work you have to do, too.

Parts to pick up before installation time

Metal mounting brackets (straps)

Car stereo radio installation metal straps examples imageCar stereo metal mounting straps are fantastic for installation and will make building & installing an amp rack much easier. You can buy them finished in black, which I highly recommend, or with the standard metal finish. 9″ straps are fine in most cases, and you can buy a 5 pack or similar to save money. You’ll need at least 4 straps if using these.

One item I highly recommend is excellent metal  mounting straps like these Metra BS9BK. They’re FANTASTIC for many types of car audio installations and are used very often by professional installers.

They’re strong enough for mounting an amp rack securely but are flexible enough to bend into odd shapes for more challenging installations.

I’ve used these for years to install almost anything in places you would think were impossible to put a sound system in!

It may or may not be possible to find some at your local stereo shop or electronics store that carries car stereo accessories, so you really need to check beforehand. Expect to pay $10 or less including shipping, although some can be found for around $7-8 for 2-4 straps.

Note: Another option is to use standard metal brackets like “mending plates” that are stocked at local hardware stores. I’ll explain more about the pros and cons of those later.

Speaker carpet vs. fabric

Car amp rack felt and speaker carpet examples closeup

Black automotive-grade speaker carpet (left) is great looking and durable. There’s no backing on it so it can be stretched and cut easily. However, you may have to order it, and it may cost more than regular fabrics like black felt (right) that you can find locally.

To finish your amp rack you’ll also need a good-looking & durable material to cover it with.

Backless automotive carpet (often call speaker box carpet) tends to be very durable and offers a great look. Colors like charcoal, dark gray, or mixed black colors are often available.

Otherwise, I recommend buying a good black fabric like felt. You can expect to spend $10 or so in that case, as it’s usually sold in 1 or 1/2 yards (1 yard = 36″). You may also find a different soft black cloth on sale while you’re there.

Suitable fabric can be bought often for a discount price locally from arts & crafts stores like Joann, Michael’s, and sometimes Wal-Mart.

Measuring installation space

Image of a car trunk and car amp rack space measured

Get basic measurements for the best place you find for installing an amp rack in your vehicle. Think in terms of fitting a large rectangle there, even if you don’t think a flat amp rack can be mounted on some areas that are curved or stick out. Don’t stress if there’s not a perfectly flat area available – that’s actually very common! We’ll cover dealing with curved or unusual surfaces later.

Begin by using your tape measure to find out how much space you have in your trunk (or cargo area, depending on your vehicle) where you can install a rectangular board.

The measurements don’t have to be super-exact but a close estimate of how much space you have available horizontally and from top to bottom. For example, measure from several inches below the rear deck of your trunk to about 1″ to the base of the trunk near the interior carpet or trim.

That should give you a good estimate of what to work with. Be sure to save in your notes the measurements you took.

Don’t forget the weight

As an assembled amp rack will be heavy so you need to be sure to measure the available space as if the assembled rack is resting on its bottom in the vehicle. T

Check for good places to mount the amp rack brackets

While you’re measuring, look for good places where you can fasten your mounting brackets when the amp rack is installed in the car.

Look for a section of the car’s metal body where:

  1. It’s safe to drill a hole without damaging anything underneath (always check!)
  2. The metal is sufficiently thick & strong enough.

In most vehicles, the sheet metal in the rear is the same thickness throughout, so that’s usually not a problem.

Planning your amp rack setup

Car amp rack planning imagePlanning your amp rack setup: place your amps on your floor and use your tape measure to estimate how much room your amps will need for clearance with wiring & cables installed. Also allow some spacing beside the amplifiers (the top and bottom of the amp rack).

Put your amplifiers on the floor and line them up as you’d like them to be placed on your amp rack. Place them next to each other with enough space so that there’s enough clearance to connect power wire, speaker wire, and RCA cables as needed.

If you’re tight on space you may need to consider using 90-degree bends for the wiring and right-angle adapters for the RCA connections.

When you’ve got the amplifiers lined up with enough space, measure a rectangle with enough clearance before and after the ends of the amps and a little extra clearance from the top to bottom.

Keep enough space!

Don’t make the amp rack spacing too small – you don’t want it right up against the sides of the amplifiers.

You’ll want to allow 2″ space or more at the sides of the amps if your installation measurements earlier will allow for it.

Write down the measurements in your notes as you did earlier.

Your shopping list and tips

Image of a paper checklist being prepared with a marker

You’ll be able to buy nearly everything you’ll need in only a few trips, but planning ahead as much as possible will save money and keep the problems to a minimum.

Give yourself enough time during the day for running around town and dealing with traffic to get what you need.  Start shopping early in the day or the before if you’d like to build & install your amp rack the same day.

I hate being stressed out and running into problems right in the middle of a project or installation, so take my advice and try to get what you need the day before if you can.

Be organized and write down or print out what you need before you go. Don’t be sloppy and cost yourself extra time, gas, and stress.

Materials list

Hardware:

With your notes, head out to your local hardware store for the following:

  • Spray adhesive
  • Metal brackets (if not using metal car stereo straps)
  • #8 Phillips head machine screws, 4-pack or similar
  • #8 washers, small package
  • #8 machine screw nuts
  • 3/8″ pan head Phillips screws
  • 3/8″ length self-tapping screws
  • Wooden board

3M Super 77 is a great spray adhesive. There are lower-cost adhesives available but in my experience, I’ve had problems with the adhesive being weak and the fabric can come off by itself. Super 77 usually costs close to $10.

3M Super 77 car amp rack fabric imageI recommend this one for car audio projects. It provides a strong adhesive and it’s reliable unlike cheaper brands that fail or aren’t very strong. You do have to be careful to not get it on you or nearby objects when using it, however. You can 3M Super 77 Multipurpose Permanent Spray Adhesive Glue, Paper, Cardboard, Fabric, Plastic,...

Choosing a wooden board

Home Depot wooden board imageYou’ll need a wooden board like this to build your amp rack. In the building materials section of your hardware store you’ll find wooden boards that are about 1/2″ or so thick and usually come in lengths of 4 ft. or longer. Pine is the cheapest but is more prone to warping and is weaker than others, but it’s suitable if you’re on a budget. It’s not suitable for installations exposed to a lot of humidity or moisture.

Using the measurements you wrote down from planning your amp rack, buy a wooden board that’s the same or close width to what you measured. To save costs buy one with length closes to your length measurements for what you need.

Quick tip: To save time and hassle, try buying your supplies at Home Depot or Lowe’s if you have one nearby. They offer free wood cutting to customers in the building supply section, so you’ll be able to tell them the length you need and they’ll do it for you.

More about metal brackets

Car amp rack installation bracket examplesMending plates and other metal brackets are sold in pairs or 4 packs for smaller sizes and individually or in pairs for the larger sizes.

As I mentioned earlier, if you’re not able to use (or buy) car stereo metal installation straps you might be able to get but with hardware store brackets.

Right-angle brackets and “mending plate” (flat) brackets are also helpful for assembling and installing your amp rack.

Unlike metal car stereo straps, mending plates are nearly impossible to bend. They’re very strong but the drawback is that they’re fixed in length and not suitable for curved or more difficult installation needs.

You can usually find them sold in packs of 2, 4, or 8 for a few dollars.

Fasteners

Car stereo installation screws examples imageSelf-tapping screws (left) make mounting brackets fast and easy if you have a cordless drill as they simultaneous drill a hole then screw into metal quickly. Regular pan-head screws (right) will work well for mounting your amps to the amp rack. Use #8 machine screws (below) and nuts with washers to fasten your mounting brackets to the rack securely. They’re better suited for this than using only pan head screws.

#8 machine screw

Machine screws work with nuts and washers. They’re great for attaching brackets to your amp rack board, for example. They come in packs with standard sizes. I normally use #8 machine screws for many projects.

Fabric/covering material

If you’re going to get fabric locally instead of ordering it, arts & crafts stores are where I’ve often found discounted black material I could use for building amp racks.

Ideally, try to get a material with a dark color that’s durable and stretchy. I recommend a strong felt material or similar basic fabric.

Be sure to ask the cashier or attendant for suggestions about what you’re planning to build. Honestly, sometimes they’re helpful and other times they’re fairly clueless when it comes to good suggestions, but at least if something is on sale they’ll normally let you know.

Image of a fabric store discount table

If you’re planning to buy fabric instead of backless speaker box carpet, try checking the clearance tables while you’re shopping. I’ve often gotten fabrics at a MUCH lower price by doing this. There’s a good chance you’ll find a deal! Black fabric is very common and should be easy to find.

Remember that fabric is normally sold in units of 1 yard (36″ in length) or 1/2 yard (18″ length) in many craft stores.

You’ll need to do just a bit of math to figure out how much you need. Try not to get exactly the same length as your measurements.

I strongly recommend you have a bit extra if it’s your first time working on a project involving fabric and a spray adhesive. Typically I use about 2 yards of material and have a small amount left over when I’m done.

The height is nearly always much more than I need.

Making your amp rack – covering the board

After having your board cut to the length you need and planned for its time to put the finishing touch on it and assemble the amp rack.

Now that the board is a length that will fit into the installation space you have and that will allow enough space for your amp wiring & cables its time to cover it and make it look nice.

Find a good place to work where glue overspray won’t get on surrounding things indoors.

Place your board on the fabric and trim it to a good size, allowing several inches past the board of extra fabric on each side. I recommend allowing at least 6″ or so, which you’ll trim as needed.

Follow the rest of the steps in the diagram below.

DIY car amp rack how to apply covering diagram

Spray adhesive is very hard, if not impossible, to remove from your clothes and other materials so be very careful when using it. Use light, consistent spraying strokes. You don’t need to use a tremendous amount, but it does help to spray some on both the wood surface as well as the fabric you want to glue.

Using adhesive on both surfaces gives an even stronger bond. After spraying, waiting about 15-30 seconds and lightly touch the glue to see if it is tacky.

If so, tightly pull the fabric over and onto the wood area you sprayed. Then rub the fabric firmly with your palm for a few moments to make sure there’s good adhesion.

The fabric, no matter how well you tried to trim it, will likely overlap each other a lot. If you have a utility knife with a sharp blade that makes trimming a bit easier than using scissors.

Otherwise, slightly pull up edges where needed, cut with the scissors, and place it back into place.

You may need to reuse the adhesive spray on some parts. It’s a bit tough to do in small sections but by quickly and gently tapping the spray nozzle you should eventually get the hang of it.

Putting it all together

Now that you have the board covered it’s time to assemble it.

Drill a 1/8″ (or close) hole in each corner and mount a bracket/strap to each hole using a #8 machine screw + washer on the top (amp) side and on the backside use a washer and nut.

Tighten securely using pliers while keeping the machine screw from turning by holding a screwdriver.

DIY car amp rack assembly diagramOnce all the mounting brackets are in place and facing the direction you need them to be, place the amps on the board and mount them using the measurements for spacing you wrote down earlier.

Be sure to leave enough length for the mounting brackets to reach the mounting points in your vehicle that you found during the first steps. 

Excess bracket length can remain hidden behind the amp rack for less hassle when installing and for a neater appearance.

Installation – Mounting your rack

Ok, it’s time for the “fun” part! Carefully put your assembled amp rack in the vehicle and begin the “fitting” process.

If you’re mounting it vertically, put as much of the weight at bottom of the vehicle and begin seeing how your brackets will fit to try to get the brackets parallel to sheet metal for mounting.

If you’re using bendable metal straps as I recommended, bend those such that they will allow the amp rack to rest on the straps when in the car.

When that’s done, hold the amp rack in place and begin doing the same for the top. Keep using trial and error until you have a pretty good way for the amp rack to rest securely in the vehicle and to have enough attachment points for the mounting brackets.

DIY car amp rack installation diagram
Once that’s finished, begin trying to use your cordless drill to drive the self-tapping screws through the brackets and into the body.

I highly recommend using washers on the screws to fit well over the bracket’s hole and keep the fit very tightThis is especially important in a moving vehicle as they vibrate quite a bit and screws may loosen over time.

If you’re having difficulty doing this step while holding the amp rack in place, then use a permanent marker to mark the bracket holes where you’d like to use the screw, remove the amp rack, then drill the screw holes alone.

Then you can return to place the amplifier rack and more easily fasten the screws either with the cordless drill & bit or with a screwdriver.

Taking your amp rack to the next level…on the cheap!

Car amp illuminated with LED lighting

Want something truly unique? You can use an LED light kit (often below $20) to add accent lighting to your cool amp rack. It’s pretty simple to do and will really get compliments from anyone who sees it.

fantastic idea is adding accent lighting to your sweet-looking new car amp rack.

Using an awesome low-cost LED lighting kit like this one under $20 mounted above the amp rack in order to glow down on them will give an incredible look and really make it shine.

I’ve done this several times (including putting an acrylic clear window in front) and people gave me lots of compliments!

Neon and LED lighting systems are lightweight so you should be able to install them using only zip ties. Overall, it’s usually very easy and it can be done on a budget if you shop carefully.

Wiring is simple as many kits can be powered by +12V directly and wired to a relay to switch on and off with your car stereo using the remote-on wire.

DIY car amp rack plans cost estimate

Here’s a good estimate of what you can expect to pay for all materials (not counting tools) depending on where you shop. Don’t forget to check your amplifier packages for screws you can use, as some include a 4-piece set.

Item Est.Cost 
Wood$10.00
Fasteners6.50
Metal straps9.50
Fabric12.00
Spray glue9.75
TOTAL:$47.75

Additional info

Take my guide and give it a try! It feels awesome when you get it all together and see how great it looks. Your friends and other people you meet will give you compliments and that’s a fantastic feeling, believe me.

Thinking about adding LED lighting? Be sure to check out my detailed car interior LED light kit installation guide.

If you’re still deciding what to do about buying amps and you’re on a budget, have a look at my great budget amplifier guide here.

How To Install A Subwoofer And Subwoofer Amp In Your Car – The DIY Guide With Diagrams

Image of a guy smiling and subwoofer install collage

Installing a subwoofer in your car yourself feels great! It’s so much fun to finally enjoy the awesome bass you’ve been missing in your music.

I’ve seen a lot over the years as I’ve done hundreds of car audio installations – and unfortunately, I saw a lot of good people end up with a terrible sounding system or heard about them getting ripped off. I don’t want that to happen to you.

I’ve put together an extensive guide to help you get started along with buying information, diagrams, installation steps, and more.  

Contents

Infographic – How to install a subwoofer in your car

Infographic for how to install a subwoofer in your car

Before you get started

Clip art image of a face thinking - Things to know content image

In order to help you understand the big picture I’ll explain the basic things we need for great sound and a successful installation:

Electrical connections:

  • +12V battery connection with a fuse
  • A good, solid connection to the car’s metal body
  • +12V “remote on” lead to turn the amplifier on or off with the stereo or ignition
  • An audio signal source (radio/head unit) for the amplifier
  • Wiring from the amp to the subwoofer

Subwoofer details:

  • A speaker made for producing heavy bass (subwoofer)
  • An enclosure designed for bass to install the subwoofer in (or a preassembled subwoofer box)
  • An amplifier with a low-pass crossover feature and enough power to drive your subwoofer (150W RMS or above is recommended)

In most vehicles, a +12V connection at the battery is relatively easy to find and route power wire to the amplifier mounting location you’ve chosen.

However, in today’s vehicles, it can be harder to find a +12V wire for the remote on connection that turns on and off with the factory stereo or the ignition switch (normally the accessory position).

This is because today’s vehicles have more wiring which is related to computerized signals and don’t use 12V. They’re often a lower voltage or are a data signal bus and can’t be used for this purpose.

There’s less time and frustration if you get the right parts and tools the first time so you don’t have to after you’ve already started. Try to get the basics you need first before starting.

Planning time

Image of a young man working on car in garage

Try to allow enough time for daylight and to avoid rushing your work, especially if it’s your first time doing your own car audio installation. If you get stressed because of time you’re more likely to make mistakes and have to redo something later. Better to plan well or stop and pick back up the next day. If you can, however, borrowing a friend’s is a huge help.

Installing a subwoofer in your car is often hard work depending on the vehicle and what you’ll need to go through for installing and hiding the wire. If you’re adding a subwoofer to a factory system you should definitely prepare for extra work.

A good estimate is perhaps 3-5 hours or more for adding a subwoofer to an aftermarket stereo and 4.5+ hours for a factory system.

The right tools make all the difference! It’s worth it to wait a bit and get all the right tools together instead of struggling with the wrong ones.

You don’t have to spend a lot of money, but if you’re a careful shopper you can usually get most of what you need without going broke.

Most of them are basic tools and are relatively inexpensive. Just shop carefully and you’ll find good values.

Get the tools and supplies you need

Image of Scosche TK12A car stereo installation kitNeed an easy start? Consider picking up a car stereo installation kit like this Scosche KT12A budget kit from Amazon.

This is one of the single best steps. Without a doubt, buying the right amplifier, speaker enclosure, and subwoofer is critical for good bass sound.

The good news is that you have more options than ever these days!

Parts to gather before you begin

  • Amplifier wiring kit (see notes below) with fuse holder, remote wire, and connection accessories
  • Speaker wire for the subwoofer (and signal connections if using factory stereo)
  • Hand tools
  • Mounting brackets for mounting down the subwoofer box if needed
  • Cordless variable speed drill – not required but highly recommended
  • Good quality electrical tape (should say “UL Rated” on the inner roll)
  • Wire (zip) ties, small bag – 6″ or 8″ are great but others work well
  • A small package of 3/8″ length #8 self-tapping screws (if you have a drill)
  • Wire metal coat hanger (great for bending into a straight piece for pulling wire)

I’m a big fan of the Black & Decker cordless drills and they’ve done very well for me for installation jobs. Here's an excellent low-priced model I recommend from Amazon.

You might also consider planning ahead to upgrade your speakers to some better sounding ones while you’ve got your vehicle already apart, too.

Amp wiring kits

NVX XKIT42 4 ga amp wiring kitA good amplifier wiring kit like NVX True Spec 4 Gauge 100% Copper Single Amp Wiring Kit with Speaker Cable, No RCA [XAPK4] includes a  fuse, fuse holder, subwoofer speaker wire, power cables, remote wire, zip ties, RCA cables, ring terminals, and cool accessories. They make your installation MUCH easier and help you avoid paying outrageous prices from local shops.

Amplifier wiring kits come in different price ranges and quality levels. Some only contain a fuse holder, fuse, power wire, ground wire, and the remote lead wire (typically an 18 gauge wire). Others also include RCA cables and speaker wire.

The best kits include installation accessories like ring terminals, zip ties, and sometimes wiring grommets.

I definitely recommend purchasing a kit that is complete. For the average amplifier, you don’t need to spend a huge amount of money for a good kit.

What you can expect to spend

If you shop wisely you can spend around $30 for a great 8 gauge kit and around $50-60 for a 4 gauge kit you’ll really love.

Note: Not all wiring is the same. Some misrepresent the wire size they contain and don’t actually contain pure copper wire or contain wire that is actually smaller than advertised but looks larger because of the wiring jacket.

Be sure to check reviews before buying. I’ve written a very helpful guide with several of the best amp wiring kits here.

Speaker wire

wire of 16 ga speaker wire

Don’t waste money on overpriced speaker wire. The main thing to remember is to buy quality wire – preferably a name brand type – with good insulation and good conductors. One wire is marked as the positive lead so you can connect it properly.

For an average subwoofer or pair of subwoofers, a small section of 16 or 14 gauge can work well. You can find 25 ft lengths or smaller for a good price.

You don’t need super-expensive brands, so don’t get talked into spending a lot of money. Just try to find a quality wire with enough length (normally on a roll) that’s priced fairly. Don’t spend excessive money on speaker wire as it’s a waste – you just need good wire.

Heads up! Speaker and power wire marked as “CCA” is not pure copper wire! Because of the rising cost of copper, manufacturers are now using copper-coated aluminum wire, which is lesser quality than pure copper wire (and less expensive).

For your speaker wire, it’s likely fine, but be aware when shopping. Sometimes the CCA note is in small print.

When connecting to a factory system with no RCA jacks, expect to also pick up a roll of small gauge wire (18 or 20 gauge is good) of sufficient length to go from the vehicle’s speaker wiring to the amplifier.

A 50 ft roll should work well for 2 pairs of speaker wire being run. If you’re wondering how much a good basic roll of wire costs, here's a good example of true copper speaker wire that's affordable from Amazon.

Amp selection

Pioneer GM-D9605 review test amp rack image

You don’t have to break the bank to get a good amp for your new audio system. Expect to spend around $100-$250 depending on the features and power you need.

This is very important but the great news is that these days most amps have the basic necessities for working with a subwoofer enclosure and producing good bass.

Remember that you can use both a single-channel (also called “monoblock”) amplifier or multi-channel amp that is bridged for more power.

Features you need for good bass are:

  • 150W RMS power for the subwoofer available (either a single amp channel or 2 bridged channels)
  • Low-pass crossover for passing only clean bass and no upper-range music
  • A mid to high-quality brand with good reviews
  • Speaker level inputs option (if using a factory stereo

Bridging an amplifier means wiring the speaker connection so that we take advantage of a built-in design feature which allows 2 amplifier channels to drive one speaker (or pair of speakers) for more power.

This typically allows 4 x the power of a single channel to be provided! (Always check the specifications to be sure of power available and the required speaker Ohms rating).

For the average person, an amplifier capable of producing 150W for use with a well-matched subwoofer and speaker is adequate. If you want real “thump” and heavy-hitting, loud bass, plan to spend more and get a model with more power.

Alpine MRV-F300 4 channel amp end viewModern car amplifiers like the Alpine MRV-F300 offer high or low-pass crossovers to block bass or upper-range music from being played as desired. The amp shown has adjustable frequency cutoffs to control what sound ranges are sent to speakers. The “Full” setting means all sounds are allowed to the speakers.

A low-pass crossover is a feature that will filter out upper-range sounds and will allow you to play only clean sounding bass. 

High pass crossover block bass and allow higher-range sounds like music to play while blocking bass that distorts small speakers.

Additional crossover options

Some also have added features like an adjustable crossover frequency (as opposed to a simple on/off switch) and a bass boost. Crossovers are a simple but incredibly helpful feature for getting the best sound and volume out of your system.

Regarding power, you can likely get by with less if using a small subwoofer (for example an 8″ or another small type of subwoofer in a premade enclosure).

For noticeably louder and better subwoofers, however, it’s best to buy the largest you can that will fit in the space you have.

Using multi-channel amps vs. single-channel (mono) amps

Both types of amplifiers have their pros and cons to consider.

If you plan to power

more speakers in the future and expand your stereo system, think about buying a 4-channel stereo. Even if you don’t use all 4 channels right now that’s fine – you can always use them later.

This leaves 2 channels to power front speakers and 2 you can use later for more speakers or bridge for driving a subwoofer.

Multi-channel amp pros and cons:

PROS:
  • Flexible and great for multiple speaker systems
  • Lots of brand and models available
  • Can be used in 2, 4, and other channel modes (bridged)
  • Popular, so often many reviews are available
CONS:
  • Tend to have lower power ratings
  • More power connections to deal with
  • May not be as compact as a mono amp

Mono amp pros and cons:

PROS:
  • High higher power available for subwoofer use
  • Often can be as compact as or smaller than multi-channel amps
  • Simpler controls in many cases
CONS:
  • Not flexible – useful only for subwoofers in most cases
  • Model choice and options tend to be more limited
  • Many are low-pass only, no full range possible

I recommend you buy a good quality 4-channel amp with 50W x 4 or 75W x 4 (at 4 ohms) that is bridgeable to 150W or more. You’ll have more flexibility in the future and won’t have to buy another amplifier.

It’s the best bet for the beginner and the average person in my opinion. It’s always smart to plan ahead.

There are some excellent choices available today including a wonderful amp I reviewed here as well!

Subwoofer selection and things to know

Boss Audio CXX12 car subwoofer product image #1

When shopping for subwoofers, don’t go for the cheapest right away. Look for a good combination of price, power rating, and features. Good reviews are a must, too.

If you’re buying your electronics and subwoofer for the first time, it’s best generally to avoid buying an enclosure and subwoofer separately unless you know the recommended enclosure volume size (in cubic feet) for the subwoofer speaker or speaker pair.

Also, I recommend you buy a sealed enclosure as mismatching a subwoofer with the wrong vented box can result in terrible sound!

I saw this many times, and it’s incredibly disappointing to see.

Not every subwoofer works with every box

I’ve done many speaker designs of various types, and here’s a simple explanation of why it matters: Every speaker has certain parameters that determine how it performs in certain types and sizes of speaker boxes.

If the speaker is not matched correctly, the sound produced can be far below what it is cable of.

This can result in “bottoming out” early (the speaker has little resistance to movement and begins to reach its limits when moving) or simply can’t produce bass sounds at a normal volume.

Your hard work will have been for nothing if that’s the case, and it feels terrible to work very hard only to get bad sound.

Example loaded car subwoofer enclosuresIt’s best to start with a subwoofer combo in which 1 or 2 subwoofers are correctly matched to the box. In most cases, a brand name box with speakers is designed specifically to work well with the speakers based on their particular characteristics. This is the most convenient option for some people. 

My advice is to buy a brand name pre-assembled (“preloaded”) or matched subwoofer speaker/box combo. It will pretty much guarantee you’ll get good sound.

If buying a preassembled box, you can’t also buy a vented (ported) model if you wish.

Ported speaker boxes generally have slightly less “tight” sound but can often play louder and deeper vs. a sealed box for the same amount of power. So it’s generally your preference.

Many small subwoofer combos are ported to get more sound from a small size.

Generally speaking, you’ll need to buy 4 Ohm subwoofers

Many amps, both single channel or bridged multi-channel amps, require a minimum speaker impedance (Ohm rating) of 4 Ohms, so bear this in mind when shopping. You can learn more about that here.

Consider buying a car powered subwoofer

A car powered subwoofer is one that is an all-in-one bass system made up of a special enclosure, matching subwoofer, and has an amplifier already built-in.

They’re easier to install than a separate amplifier/subwoofer system.

Additionally, they’re a great choice for people who may later change vehicles especially people who own leased cars. The total cost for a powered subwoofer vs. separate items may be lower, too!

Image of MTX AUDIO RTP8A powered subwoofer side viewA powered subwoofer is an all-in-one solution for subwoofer bass. Although many are extremely compact to fit in space-limited vehicles, some like this one offer bass nearly as good a more expensive amp & speaker box. Typically their overall cost is less or the same as buying the items separately. There’s also no amp to worry about mounting, too!

They do have drawbacks, however: while they offer a more convenient way to install and remove the audio system, they tend to be more likely to have lesser performance than by using a standard amp and box system.

Car powered subwoofers tend to be more oriented to solving the problem of limited space in a vehicle and may be more limited in their speaker size, amplifier power rating, and the bass volume they can produce.

Note that they’re generally great choices if you want good but not extremely loud bass in your vehicles.

Some models, however, feature larger speakers and high power built-in. I’ve covered this topic and show some great examples here.

Pro Tip
Whenever possible, if buying a powered subwoofer, get the largest model you can fit into the space you have available. Under-seat and other ultra-compact models produce some bass that adds a good extension to your music, but there’s no substitute for true air displacement like from larger subwoofers. The best sound generally comes from larger speakers like 8″, 10″, and 12″ speakers.

Tools I recommend for a successful installation

Example of a toolbox full of tools

I’d consider the following tools essential:

  1. Phillips & flat head screwdrivers
  2. Good & inexpensive wire cutting pliers
  3. Needle nose pliers
  4. Utility knife with a retractable razor blade
  5. Miniature flat head screwdriver or another similar tool to pry apart plastic trim panels and adjust the amplifier gain at the end

Ideally, you’ll have access to these as well, although I realize sometimes they can cost more than they should:

  1. Digital multimeter (test meter) for measuring voltages
  2. Cordless variable speed drill with clutch (absolutely FANTASTIC for speeding up work, drilling holes, and driving screws!)
  3. A good crimp tool & crimp connectors
  4. Wire stripper (not a need but greatly simplifies work effort)

Some of these can be bought at stores like Wal-Mart or Harbor Freight for a discount price. However, it’s hit-or-miss whether they carry all the items you need. Most can be bought for cheap on eBay or Amazon.com.

I’ve been very happy with my digital multimeter from Harbor Freight. It was a great deal, and has lasted well! (Note: they also carry a cheap $3-5 budget version that will work also for installation troubleshooting).

Image showing example crimp tool and crimp connectorsA crimp tool (shown with crimp caps) is a great tool for a professional-quality installation to avoid having issues with wire connections later. I recommend blue butt connectors (right) as they’re a bit easier to use and fit 16-14 ga. wire but can also be used with smaller gauge wire if you fold it underneath itself before inserting it.

Installing subwoofers into a box

If you’re following my recommendation for buying a preloaded subwoofer box, then the work should be done for the subwoofer itself. If you buy an enclosure and subwoofers separately, you’ll need to install them securely.

Image of subwoofer installed in box and drywall screw

Install the subwoofer in the box.

I highly recommend using a cordless drill and drywall screws as they go quickly into the wood material of the box.

Most subwoofers use 8 screws. Don’t skimp on this! Subwoofers are heavy and have a lot of vibration when in use. It’s best to make sure they’re securely fastened.

If the cordless drill has a clutch set it to one of the first or lowest acceptable settings to make sure you don’t strip out the box material when fastening down the speaker.

Installing your amp & subwoofer

Here’s a general diagram to help you visualize the installation:  (Click to enlarge or click here to get the .pdf you can view or print)

How to install subwoofer and car amplifier infographic diagramInstalling an amplifier consists of several basic steps:

Route the positive wire cable to the car battery and hide it underneath the carpet and interior trim on the battery side of the vehicle.

In order to do so, you’ll need to pull up some of the interior plastic trim like rocker panel covers which usually snap off and snap back into place. Always be careful, and if necessary, carefully use a flat head screwdriver between gaps to help pry them off. Pull back the carpet to find room to hide your amp wire.

You can then find the edge of the carpet which is usually easy to pull back and tuck wire into.

Running wire to the car engine and battery

Honestly, getting the wire to the battery is usually the toughest part you’ll face. But don’t worry, there’s nearly always a gap, hole, plug you can remove, or a rubber wiring harness seal you make a hole in by pushing a screwdriver or similar tool through.

With a flashlight, look underneath the dashboard and try to find a plastic filler plug that can be pushed out (exposing a free hole you can use) or a rubber seal with a factory wiring harness that goes into the engine compartment.

If you need to do this, use a punch, pointed object, or even a very strong and long screwdriver to put a hole in the rubber seal. Then use the “coat hanger trick” to act as a wire snake for help pulling the wire through.

Image of positive amp wire pushed through firewall grommet

If possible, push a hole through a firewall wiring harness seal (“grommet”) and push the amp wire through that.

If by chance you find a plastic hole plug like this pop it out using a screwdriver and use it as a ready-made power cable hole. That makes things MUCH easier!

Image of engine compartment wiring harness rubber seal amp wire install

If you’re going through a factory wiring harness seal as pictured in the 1st pic, push it through until you can grab the wire and then from there pull it through the engine compartment. Then you’re past the hardest part!

The coat hanger trick

Image of straightened coat hanger

A useful trick is to use a coat hanger to make a “wire snake” to pull wire through tight and difficult areas, especially when going from the interior into the engine compartment.

With some pliers, you can straighten out a standard coat hanger to create a “wire snake” which is a tool used to pull wire through small spaces.

After doing so, you can wrap electrical tape around the power wire and attach it to the end.

Then push it through the car interior (if no easier alternative is available) and into the engine compartment, where you can then finally pull it through by hand and remove the power wire from it.

It’s best to bend the ends so that they’re rounded and won’t snap easily on obstacles in the way. For best results, make a small loop on the end where you want to attach your wire and wrap it well with electrical tape to smooth over sharp edges that may snag.

Running the wire the to back of the car

You may find it easier to remove the back seat and find a gap that will allow you to easily run the wire to the back. I usually find it best to first try to find a space where I can push my hand or fingers into the side gap of the rear seat (as the base of the top half of the rear seat) and find out if there’s a space available.

If not, I’ll try using the coat hanger trick, which almost always works.

Connect the positive wire to the fuse holder.

This is very straightforward. Trim about 1/2″ insulation from wire ends and assemble the fuse holder onto the exposed positive wire. Connect a crimp ring terminal and crimp using vice grip pliers (or other strong pliers) or a crimp tool.

Place the fuse holder near the battery with approx. 12″ or less of wire length, as that’s a general rule used to make sure there’s not enough wire to possibly be in a short-circuit without fuse protection which could cause a battery explosion or cause your vehicle to catch on fire.

Don’t think so? It happens! It doesn’t take very much for a pinched, unprotected wire to start melting the insulation and for a fire to start.

 Don’t install the fuse yet!  rimp ring and lug terminal examplesI highly recommend crimp ring terminals like those in the left picture and not those in the right picture (lug terminals).

It’s because lug terminals are far harder to crimp and may need soldering to make the best connection. 5/16″ ring terminals like those on the left are excellent and easier to use as well as being included in many good amp wiring kits. They’re also not very expensive.

If you can’t get the rubber sleeves to fit over your wire, don’t worry too much and leave them off if necessary.

Avoid lug terminals like those shown here. I’ve discovered that while they’re sold in some amp kits and are also sold in parts stores, they’re very difficult to use and need special high-force crimp tools or high-heat soldering tools.

They may very well keep you from getting your amplifier wiring installed, and I’d hate for that to happen

Connect the positive cable securely to the battery.

Use the ring terminal to fasten to a battery clamp bolt or stud. Use sandpaper or a wire brush to remove corrosion and expose clean metal if necessary.

Car amplifier positive wire and fuseholder installed at battery

For the best method, use a crimp ring terminal to attach the positive wire to the battery clamp on a stud or bolt. Be sure to remove the fuse before doing so, and install the fuse holder on the wire before connecting it to the battery. Hold in place by using zip ties to attach to nearby wiring, hoses, or brackets.

Connect the amplifier ground wire to bare metal near where the amplifier and subwoofer will be placed.

Use a crimp ring terminal and secure it to the car body (bare metal) with a factory screw or bolt. An alternative and faster solution is to use a cordless drill and self-tapping screw to drill into the metal and fasten the ring terminal at the same time.

Car amp grounded to factory ground location

If you can find a factory ground wire location in close range it’s an excellent ground wire connection point. Otherwise using a self-tapping screw and a cordless drill make the work very quick.

Connect the remote-on lead to the aftermarket car stereo and signal source

If the stereo in use is an aftermarket model a remote lead output wire should be available (blue or blue and white). Connect this to your remote on wire included with your kit.

If no aftermarket car stereo is installed, it will be slightly harder. In that case you have a few options:

  • Run the remote wire to a +12V wire switched on with the ignition or the accessory position of the ignition switch (this is the 1st choice)
  • Use a specialized adapter which senses music and when connected to a power supply can provide a remote lead signal

The 2nd option shouldn’t be necessary except in really tough situations.

Almost always you can find a +12V switched wire somewhere in the vehicle. It may take time, but using a good multimeter you can locate one and then connect similar to the speaker wiring connections shown below.

On most aftermarket car stereos a blue output wire is for switching an external amp on and off. It supplies +12V when the stereo is turned on. Connect to this if available. I normally use butt connectors (crimp connectors) for connecting wire securely.

Connecting the RCA cables – or connect speaker wiring if RCA jacks are not available

Remove your car stereo and get access to the rear wiring or rear of the stereo if it’s and aftermarket (non-factory) model. Connect to the RCA jacks if available in the following order of preference:

  1. Subwoofer output jacks (often marked SUB or SUBW)
  2. If 4 are available, use the REAR jacks
  3. If only 2 are available, then that’s fine as well

The left channel is marked with a white jack and red represents the right channel.

Plug your RCA cables to the rear of the aftermarket stereo, if available.

Connecting to speaker level inputs (if you have a factory system)

If no RCA jacks are available or you have a factory car stereo, you’ll need to tap off of speaker wiring to get an audio signal source. This may be easier to do while you’re connecting the remote wire at the stereo. If there are rear speakers in the vehicle, that’s another option too as speakers in a trunk may have fairly easy access to speaker wiring.

You need to find wiring information for your vehicle and check at sites like the12volt.com for wiring charts.

Image showing car speaker wiring tap how to

At each pair of speaker wires or near the speaker wire connector, strip off about 1/2″ of insulation and tap off it. To do so, either wrap wire or cut the factory wire and connect to it using crimp connectors while attaching a small gauge wire when doing so.

Crimp connectors (see the tool list above) are reliable and make good electrical contact. I recommend you use those if possible.

Image of car stereo wires crimped

Route wiring to the amp location

After connecting the power wire, remote wire, and signal wire move it down to the same side of the car (as needed) and when the wire comes together use zip ties (also called “wire ties”) to neatly hold it all together. Use wire cutters to cut off the extra remaining zip tie length.

Wire bundled with zip ties exampleBundle your power and cable wires together neatly like this. To save money you can space out zip ties roughly 12″ or so apart to avoid using too many. The ties hold wiring in place, make it more manageable, and help keep things from moving around over time.

Mounting the amplifier

Example of 2 custom car amp installations

Two amplifier mounting ideas that work for nearly all installations. Don’t sweat it! One of these should work. However, the board mounting idea looks much better and means you can mount your amp out of the way in many cases.

For most people there are 2 great and simple ways to mount your amp reliably:

  1. On the subwoofer box
  2. Make an amp mounting board and attach it to the car securely

I prefer #2, as it’s a better looking and more professional method. It’s slightly more work than #1, but looks wonderful and it also avoids subjecting the amplifier to extreme vibration like when mounted to a subwoofer box.

For option #2 you can buy a nice speaker box carpet or a dark fabric from Joann or some other fabric/crafts store and cover the board using an adhesive spray and/or a stapler, then mount it using brackets or car stereo straps.

Black fabric is available in a variety of fabric types (I’ve used black felt or velvet-like materials often for custom installations).

A big advantage of using a custom-cut amp rack (amplifier board) is that it allows installation in locations otherwise not possible.

Just cut a section of board (bought from Lowe’s or Home Depot for example) slightly larger than the amplifier, mount it using brackets or straps, and that’s it.

As long as you have room and the parts for mounting the board, it’s relatively easy! You can find some great ones I use here.

Car stereo installation pan head screw and metal strap examplesUse pan-head screws (left) and not self-tapping screws when you’re mounting items to wood or wood-like materials. Car stereo installation straps (right) are fantastic for custom mounting amplifiers, amplifier boards, and subwoofer boxes to a car.

Connect all wiring to the amp and the subwoofer

image of car amplifier having wire connected

This is the easy part! And you’re in the “home stretch” – there’s not much left at this point. If all goes well, you’ll have awesome sound really soon.

With the power turned off and power wire fuse removed, connect the power wire, ground wire, and remote wire to the matching terminals. Normally the positive and negative terminals are larger than the rest.

Make sure you have a good, tight connection without any stray wires sticking out in a way that may lead to a short-circuit.

(Click to enlarge & zoom)

Image with diagram of how to bridge an amplifier

Connect the larger speaker wire you bought to the speaker terminals of the amp. If you’re using a bridgeable amplifier connect the wires to the amp in a similar fashion as shown here. If using RCA inputs, connect to the input pair for the speaker outputs you connected to.

If using speaker level inputs from a factory system connect them now. They should be labeled and/or color-coded to make it more clear.

Power on the system and check for problems

Install the power fuse and turn on the ignition and your stereo. You should hear sound and the amplifier power light should indicate that it’s on. If not, check the following items for problems.

Quick Tip
Use a test meter when possible for troubleshooting amplifier problems. Test lights don’t give you enough information. Many amplifiers can have a good ground and +12V battery connection but won’t turn on if the remote lead is below a certain voltage, for example, so it’s important to be able to find out what’s going on.

If you don’t have sound or power, it’s more than likely due to one of these common causes:

  • Poor car ground wire (measure continuity between the amp negative terminal and a metal part of the car)
  • Fuseholder problem or bad fuse
  • Remote wire voltage is too low or +12V isn’t being supplied at all

Generally, there are only a few reasons why an amp can’t turn on and produce sound, so it’s normally one of a few basic problems like I’ve listed here causing the problem.

Setting the gain and bass adjustments

The problem with having sound adjustments on both the stereo and the amplifier is that settings can be all over the place and one can affect how the other produces sound to your subwoofer.

I recommend doing the following:

  1. Turn off all bass boost or equalizer (EQ) functions on the stereo or set to mid-level or zero.
  2. Turn off any bass boost controls on the amp or turn to the minimum level
  3. Set the amp gain to its minimum

Alpine MRV-F300 4 channel amp end view

Most well-designed amps like the popular Alpine MRV-F300 feature flexible crossover controls you should use. With them, you can get clean, low-distortion music power at high volume. Surprisingly very few people use these features to their potential!

Play some music you’re very familiar with and that you know should have good bass sound at a moderate level. Then with a small screwdriver or screwdriver bit that fits adjust the gain until bass performance is at the level you enjoy.

Don’t forget that when an SUV hatch or car trunk is closed the sound will be changed somewhat as opposed to when the door, trunk, and/or rear hatch are closed.

In case the stereo has insufficient bass or your system still doesn’t sound quite right, try using the bass boost on your amp if available.

A bass boost typically works boosting bass response around a fixed or adjustable frequency near 50Hz for example. These can sometimes add some extra “thump” and bass extension to your audio system.

Summary

I hope my guide has provided a lot of helpful information. That’s what I’d love to do because I want everyone to know how great it feels to install your own car subwoofer and amplifier.

One important tip: for factory-installed “premium” audio systems like Bose, JBL, and Harmon Kardon it can be difficult as those systems are far more complex.

Generally speaking, you should still be able to add a subwoofer by tapping off of a pair of factory speaker leads in most cases.

If you run into problems or don’t feel up to the task consider getting an estimate speaking with a reputable car stereo shop. If they say your vehicle will need parts and add-ons not listed here be sure to ask why.

Add-ons are a very big moneymaker for car audio stores.

Whatever you do, don’t feel intimidated. Follow my advice here to be better prepared and take your installation one step at a time.

Nearly everyone can install their own subwoofer in their car and enjoy fantastic bass!

Recommended items

As I mentioned in my guide, I generally recommend using a multi-channel amplifier. Here’s a great list I’ve put together of some of the best affordable and well-performing models.

Here's a very good and complete amplifier wiring kit to make the job easier (I’ve found some of the best values at Amazon).

One of the best car stereos I’ve found is this Alpine CDE-HD149BT Single-Din Bluetooth Car Stereo with HD Radio, Premium LCD Display and...

Print outs

  1. Basic how-to infographic (.pdf file)
  2. Car amp installation diagram
  3. Basic speaker wiring diagram for woofers

Got questions or comments? Feel free to leave a comment below or let me know.

How To Bridge An Amp – Info, Guide, and Diagrams

Image showing a car amp during installation

Bridging an amplifier can seem like a strange and almost “magical” concept. If you need help figuring out how to bridge an amp, you’re in the right place!

Let me help you understand what bridging is, why it matters, and how to bridge your amp.

It’s easy to make mistakes and – unfortunately – you can permanently damage your amplifier and even your speakers. Don’t worry though as I’ll cover what you need to know before that happens.

Contents

What is car amp bridging?

Diagram showing a 4 channel car amplifier bridged to 2 channels

A 4 channel car amplifier bridged to 2 channels. This is a very common wiring use of a 4 channel amp for situations in which you’d like more power available and don’t need 4 separate amplifier channels.

Bridging is a special feature in car amplifiers which lets you get the maximum amount of power they can produce by using a built-in channel-sharing design.

It means using 2 amplifier channels working together to drive a speaker or a set of speakers with by using the power that normally is split between 2 separate amplifier channels.

It’s actually a pretty cool subject, and very useful! For example, I have owned many car amplifiers and normally used 4 or 5-channel amplifiers. I used 2 channels, in bridged mode to drive a single subwoofer or a pair of subwoofers in the trunk.

This meant having more power available at my disposal and more flexibility even if I changed my speaker setup later.

How does an amp make more power when bridged?

Pioneer GM-D9605 internal components and circuit board images

Internal view of a car amplifier. The output sections have one channel per pair designed to provide the bridging option when needed. In normal use with 1 speaker per channel, you won’t notice a difference as they’re wired normally and have separate audio signals.

This is actually a very cool and fascinating subject. If we do the math, we’ll discover something very interesting!

How about we take a real-life example and I’ll show you exactly how this works?

Example #1
A 2 x 50 watts/channel amplifier is connected to two 4 ohm speakers. With some math, we would find out that our little example amplifier puts out 14.14 volts when it reaches 50W into a 4 ohm speaker.

We can find the power using this formula: Power (W) = (Volts x Volts) / Ohms, or P = V^2 / R.

So (14.14)^2/4 = 50W for each amplifier channel.

Example #2
We connect the same 2 x 50 watts/channel amplifier in bridged mode across one 4 ohm subwoofer.

The voltage available across amp’s bridged channels working together in a push-pull fashion is:

Total voltage: 2 x 14.14V = 28.28V

Power across the 4 ohm subwoofer: V x V / R = (28.28)*(28.28) / 4 = 800 / 4 = 400W in bridged mode. (Assuming the amp is designed to support that much power output)

So by bridging the amplifier in this example, we can get close to 400W – yes 4 TIMES – the normal available power when in bridged mode, depending on the connected speaker.

Note: It’s important to remember that we’re assuming a few things, like that our amplifier is rated to provide that much power.

Not all amps can deliver that much – it depends on their limitations and how they’re designed.

Also, note that in this mode each channel is handling several times the electrical current it had to before. Therefore it will draw more power from the car battery.

How do car amps make this possible?

The reason this is possible is that today’s car amps have a design in which one of each 2 audio channels is actually inverted (you can also say 180 degrees out of phase) but is normally connected at the output in a non-inverted fashion.

You’re normally not aware of this as it has no effect on the end user.

This means that in bridge mode the bridge connection is made so that the amp channels have a difference of the available voltage at each output. This voltage difference is twice that of one channel alone.

Connecting to a bridgeable amplifier – how to bridge an amplifier

Image with diagram of how to bridge an amplifier

Bridgeable amplifiers normally have the terminals labelled accordingly. In that case, bridging is easy to do as long as you observe speaker impedance (Ohm rating) warnings from the manufacturer

The good news is that many car amplifiers sold today can be bridged. Note that some (especially smaller, lower-cost products) may not have the feature built in so it’s very important check before buying one. 

Never assume you can bridge an amp.

To bridge the amp, connect the subwoofer or bridged speaker positive (+) terminal to the positive amplifier bridged terminal label, and the speaker negative (-) terminal to the negative bridged amplifier terminal also.

Use good speakers & reliable connections

Image showing example of speaker terminals with crimp connectors used

It’s important to use a good reliable connection for speakers. Car and trucks are subject to vibration and lots of movement, so a poor connection can cause problems over time.

Since bridging means that much more power is now available to you speakers (more often than not this is used for subwoofers) it’s best to use a quality speaker wire and make secure, tight connections on both ends.

Before doing so, verify that you have met the required minimum impedance (speaker load, in Ohms) as specified on your amplifier or its instruction manual.

For today’s car amplifiers this is a minimum of 2 ohms when bridged, usually. Some do support less or need 4 ohms but for best results and to make sure you are setting up your system to the best of your requirements it pays to be sure.

Quick Tip: some older model amps and a few modern amplifiers have a “bridge mode” switch that must be used or may require only one RCA audio connection is made. Always make sure you’ve checked!

Don’t forget the crossover

As long as you have the correct speaker impedance in use (see my additional info below) you should be ready to use your bridged amplifier! Note: it may be necessary to set the built-in low-pass crossover also, if available. I’ll cover more about that below too.

Note! You must be sure your amplifier can handle a bridged connection. Not all amplifiers are designed to do so, and most home stereo receivers and home theater amplifiers cannot support a bridged connection.

ALWAYS VERIFY BEFORE ATTEMPTING TO BRIDGE AN AMPLIFIER!

See my additional information below if your amplifier doesn’t support this by design

Understanding the minimum speaker load (Ohm rating)

Image showing an example of how to test speaker ohms with a multimeter

Shown: An example of measuring the speaker impedance (total resistance) in Ohms for a speaker’s voice coil.

Your amplifier should state in the owner’s manual the minimum required “impedance” (the resistance load a speaker has) for use. This includes both for normal stereo usage as well as a rating for bridge mode too.

If you cannot find the documentation anywhere a good rule of thumb for car amplifiers is to use 4 ohms.

Often you’ll see the phrase “stable to 2 ohms” or something similar to describe what the amplifier can handle.

Here are the basic rules for correctly connecting speakers in bridged mode:

  • You can connect a SINGLE speaker of the required minimum impedance or higher
  • You can connect MULTIPLE speakers if the total adds up to the required minimum impedance or more (see diagram)
  • Dual-voice coil speakers can be used if they can be wired to give the correct amount

Bridging examples

For an amp that requires a 4 ohm load minimum when bridged use:

  • One 4 ohm subwoofer
  • TWO 8 ohm subwoofers wired in parallel ( 8 / 2 = 4)
  • ONE dual 8 ohm voice coil subwoofer wired in parallel (gives 4 ohms)
  • TWO 2 ohm woofers connected in series (2 + 2 = 4 ohms)

For an amp that requires a 2 ohm load minimum when bridged use:

  • One 2 ohm subwoofer
  • TWO 4 ohm subwoofers wired in parallel ( 4 / 2 = 2)
  • ONE dual 4 ohm voice coil subwoofer wired in parallel (gives 2 ohms)
  • FOUR 8 ohm woofer wired in parallel (8 / 4 = 2)

Amp bridging wiring diagram

Here’s a diagram showing the most common wiring setups most people will use for typical amplifiers.

(Click to enlarge or click here to get the Adobe .pdf file you can download and print)Infographic diagram for how to bridge an amp and connect to speakers correctly

Quick tip: For most systems, if using 2 speakers, connect them in parallel to ensure each receives the maximum amplifier power vs. connecting the same speakers in parallel.

Setting the crossovers on a bridged amp

Close up image of a car amp crossover controlsClose up of a modern typical car amp with built-in crossover features. This allows high-pass, full-range, or low-pass use with adjustable sound range controls in this case.

For most bridged amp situations where the amp is connected to a subwoofer or set of subwoofers, this is what I recommend:

  1. Set the crossover switch to low-pass filter (LPF) or similar on your amplifier
  2. Adjust the LPF dial, if available, to the maximum level
  3. Play music contain bass you’d normally listen to
  4. Begin turning the LPF dial down until almost no voice or upper-range music is heard (note: for reference, a good rule of thumb is 80 Hz or lower in case you’re able to know the actual cut off frequency of your amp)
  5. Adjust the gain if more higher-volume power is needed when the volume dial of your stereo is turned up

Can you bridge an amp without bridging built in?

Amplifiers without the feature built in are unfortunately difficult to bridge, but it can be done. Several solutions exist:

  1. Build your own bridging module (read more here)
  2. Find a bridging module (these are likely very old and hard to find, but may be possible on eBay)
  3. Use an electronic crossover with adjustable phase (0-180 degree control) for each channel and set 1 of the 2 to be 180 degrees out of phase

Unfortunately, unless you’re a hobbyist and are good with electronics (and have the right tools and parts), ideas #1 & #2 aren’t very practical.

It’s much easier to buy an older electronic crossover or an inexpensive crossover that has a bridging or mono feature provided.

Tri-mode capable amplifiers

Diagram showing a car amplifier with tri-mode wiring connections

Example of wiring speakers with a tri-mode capable amplifier.

Amps that have a “tri-mode” or “tri-bridgeable” feature are the same as other bridgeable amplifiers but can also be in bridged mode and wired to 2 speakers at the same time. This makes it possible to keep a regular stereo pair of speakers connected while the amp is bridged and connected to a woofer or other speaker.

This is normally not used by most people, however, it does have some benefits as well as drawbacks.

  • Pro: This allows a 2-channel amp to connect to 3 or more speakers
  • Con: for woofer use on the bridged output, an external passive crossover is needed – these are often large, heavy, and expensive for low-frequency speakers like subwoofers

Summary

Bridging your amp should be a fun, easy, and enjoyable way to get more power for your money. It’s a nice way to get system flexibility as well.

When it comes to amplifiers it’s important to have a good, solid wiring connection. Make your installation easy – check out this great post with the top recommended amp wiring kits for your money.

Questions, comments, or suggestions? I’d love to hear from you! Let me know in the comments below or you can reach me here.

The Speaker Wiring Diagram And Connection Guide – The Basics You Need To Know

Image of home and car speakers to be connected

We all enjoy music and speakers make that possible – but it’s confusing if you’re not sure how to connect them the right way.

In this post, you’ll find clear and detailed speaker wiring diagrams that to help (and that you can print out if you like, too!).

I’ll go into detail about the right and wrong way to wire speakers and connect them properly to your stereo or amplifier. It’s actually pretty simple once you learn the basics.

Contents

Printable speaker wiring diagram

Click on the image to enlarge it or click here for the Adobe .pdf version you can download and print.

Image of illustrated speaker wiring diagram

Speaker basics and speaker wiring explained

1.  What is speaker impedance? (the “Ohms” rating)

Speakers, much like other electromechanical devices, all have an electrical resistance to the flow of electrical current, much like a standard resistor, a light bulb, or many common items you’re familiar with.

The difference is how they behave when music is present when they’re connected to a musical amplifier of some sort.

The resistance value comes from a long coil of wire inside each speaker called a voice coil. A voice coil is a coil of wire that, when placed inside a magnetic field, makes the speaker move and produce sound when driven by an amplifier.

Example of a speaker voice coil close up

Speakers contain a long wound loop of wire called a voice coil. Loops of wire have a property called inductance which affects a speaker’s resistance value depending on the frequency (sound range) being played.

As they have electrical properties that include inductance and capacitance, their “total resistance” can actually change with the music slightly. Because of this, there’s some extra math needed to figure out the total resistance.

The word used to describe this is called impedance.

Speaker impedance is just a more advanced way of finding the total resistance, and by tradition is measured in units called “Ohms.”

The good news is that you don’t have to worry too much about the details – it doesn’t matter for basic speaker use, and long as you understand the basic rules you’ll be fine!

2. Stereo and amplifier minimum impedance ratings

All amplifiers of any type – where it’s a car stereo amplifier, home stereo receiver, home theater amplifier, and so on, have a minimum Ohms (impedance) rating. It’s important that you pay attention and don’t exceed the minimum speaker impedance rating.

This is because as the impedance is lowered, the electrical current increases and the stereo has to do more work. This increases the amount of stress and heat it has to handle.

If your stereo is labeled by the manufacturer as being “8 ohm speaker compatible” or similar, that means connecting lower impedance speakers can cause excessive heat and possible damage very quickly.

For example, connecting a 4 ohm speaker to an amplifier that is labeled as working with 8 ohm speakers would mean it would have to produce double the electrical current to the speaker!

Image of the rear of a stereo receiver and speaker impedance terminals

Image of the rear of a home stereo receiver/amplifier. The recommended speaker impedance ratings are usually listed above the speaker wire posts. A home stereo, for example, may often list 6-16 ohms as being ok for use.

Also, attempting to wire two 8 ohm speakers in parallel to an 8 ohm stereo would have the same effect. (Two 8 ohm speakers in parallel is equal to 4 ohms total that the amp will see)

I’ve seen many attempts by people who had friends who claimed they could “boost the power” or “get more power” by some claimed trick, but it doesn’t work. They ended up with a burned-out amplifier.

An amplifier can only handle so much heat and stress before it fails, so be sure to observe these rules. Be sure you wire speakers to meet the minimum Ohm rating you need.

Remember: don’t use a speaker impedance below the rating given by the manufacturer. Overheating or permanent damage can result. I’ve seen it happen!

3. What is speaker polarity?

Speakers are different than other devices in that they work using alternating current (AC) instead of direct current (DC). This is good news! It means you can’t harm your speakers in most cases by having the positive (“+”) and negative (“-“) wiring reversed.

Unfortunately, it gets just a little bit more complicated when we use more than 1 speaker.

Speak polarity and why you should match speaker connections

As I mentioned, speakers work by moving a cone back and forth in order to produce sound. If you wire 2 speakers in a stereo with different polarities (for example, one has positive and negative wired as labeled, and the 2nd speaker has the opposite) an interesting thing occurs: they’re out of phase and some sound cancels out.

The result is a strange and poor sounding stereo. In most cases, you’ll notice a lack of bass sound and it won’t sound pleasing to the ear as expected.

Diagram showing speakers in and out of phase

When speakers are wired the opposite of each other sound waves cancel out. When wired the same, sound waves add together for more sound.

Speakers that are wired differently sound poor because much of the sound is canceled out. Basically, it’s simply because sound waves from one speaker are moving in the opposite direction of the other speaker – and if they’re close to the same time and frequency range, often they cancel out.

This is why when 2 woofers are placed in a box and are wired in parallel but with opposite connections to each other, they are “out of phase” and have almost no bass! It’s because they are doing the opposite work rather than working together to produce more sound.

While one is moving up, the other is moving the opposite direction, and so on.

So the most important thing here to remember is to wire speakers consistently the same way as each other.

4. Wiring 2-way and 3-way speakers

2-way speakers, such as home stereo or car audio component speakers, are those which come as a pre-designed speaker set and use a crossover. The job of a crossover (also called a passive crossover, because it use basic capacitors and inductors rather than electronics) is to restrict the music production each speaker tries to produce.

For example, tweeters can’t reproduce bass frequencies (and can in fact be damaged by them) so a 2-way speaker crossover is used to prevent this. Similarly, a woofer can’t produce high pitch sounds well and is prevented from doing so.

Unlike standard separate speakers, 2-way and 3-way speakers that have a crossover can only be used in parallel and not in series.

This is because unlike separate speakers with no crossovers, in this case, many sounds will be filtered out. What this means is that little to no sound would be produced if another 2-way speaker is connected in series.

Image for 2-way speaker diagram examples

Therefore if you have a home stereo or car stereo in which 2-way speakers are used, you’ll have to add more 2-way speakers (if the total impedance can be supported by the amplifier) or add more amplifier channels for more sound.

5. Doubling the number of speakers or amount of power does not double the volume

In some cases, more speakers can be added to increase the amount of volume you can get or to place speakers in more rooms, more locations in your vehicle, and so on. You also may have wondered what would happen if you bought an amplifier with twice the power of your present one.

There’s one important thing to understand, however: having 2 or 3 speakers instead of one does not double or triple the sound. It increases a few decibels (dB) for each speaker added.

Doubling the power does not double the volume either.

This is because of how the human ear works and the physics of sound, along with how speakers work and how much volume they can produce for a given amount of power.

Generally speaking, the human ear will hear a very small amount of volume increase for each doubling of acoustic power: about 3 decibels (dB). For most people, the small amount of volume increase you notice when turning up a volume knob 1 notch is somewhere around 3dB.

Example volume produced by a typical speaker at different power levels:

  • 1W = 89 dB
  • 2W = 92 dB
  • 4W = 95 dB
  • 8W = 98 dB
  • 16W = 101 dB
  • 32W = 104 dB
  • 64W = 107 dB
  • 128W = 110 dB

So as you can see, doubling the amount of power you can drive a speaker at does not mean you’ll double the volume. It increases it a very small amount (as far as your ears are concerned).

You can also see from above that really cranking the volume takes a lot of power!

How to get more volume from speakers

The best ways to get more volume  in most cases are:

  • Use more efficient speakers (speakers that produce a higher dB volume at 1W of power – higher is better)
  • Add more speakers if you have an amplifier that can support it
  • Use higher-power rated speakers and a larger power amplifier if a lot more volume is your goal

Most people need an amplifier that can produce enough volume to fill a room or vehicle and turn up the volume from time to time. I like to use 50W or higher per channel as a good rule of thumb when buying an amplifier.

How to read speaker positive and negative labels (+ and -)

Home stereo and car speakers normally often use a red or plus sign “+” to indicate the polarity for the speaker wiring terminals which you connect your wiring to.

Here are a few things to know there as well:

  • In some cases, a black dot or a red or black stripe is used to mark the positive terminal
  • If a speaker has terminals of 2 different sizes, the larger of the 2 is normally the positive one
  • For speakers with wire already attached, typically the brass or golden-colored wire is the positive one
  • For speakers with wire attached but the same colored wires, most have some small printing on the positive wire – be sure to check closely

Summary

Here I’ve provided you with a speaker diagram showing basic connections, I explained several important things you need to know about speakers and speaker wiring. Hopefully I’ve given you more understanding about how to connect speakers and get the most enjoyment out of your system.

Have questions, comments, or suggestions? Be sure to leave a comment below or send me a message.

Confused about tweeters? Here’s a helpful guide explaining what tweeters are and what they’re used for.

Interested in bridging your car amp?  Find out how to bridge a car amp in this post.