How To Pick A Good Amp Wiring Kit + 5 Top Picks From A Pro Installer

Best amp wiring kit featured image

Installing a car amplifier is already enough work without having to worry about finding the right wire & parts. What you might not know is that there are some gimmicks being played by some companies and you could end up getting ripped off!

This post is a really helpful buyer’s guide with a list of some very good amp wiring kits with brief reviews.

As an installer, I can tell you that I’ve seen both great and terrible wire in amp wiring kits. To make things easier I’ve put together a list of some of the best wiring kits for your money.

Contents

What makes a good amp wiring kit?

Image of a man thinking about good wiring kit features when shopping

The basics to look for

Generally speaking, a great amp kit is made of a combination of things:

  • Includes most or all of the items you need for a great installation
  • Quality wire that with a conductor size that meets the advertised claim
  • A good fuse holder and power wire connectors that provide good electrical connections
  • Sufficient wire length
  • Good value and reasonable price

I’ll go into more detail here to help explain what I mean. When talking about things like “amps” (amperes, a measurement of how much electrical current is flowing) it’s important to know the basics.

Included items

Scoche 8 gauge amp wiring kitA good amp kit is made of quality wiring and includes all the basic items you need for most installation – including wiring with enough length. Zip ties help keep the installation neat and hold wiring in place during installation. Crimp terminals help you get a solid and reliable connection that can handle high power demands.

I generally recommend a kit with the following items:

  • RCA cables of good quality; ideally around 16 ft in length or longer
  • A good remote wire
  • Positive wire: good stranded conductors with about 18 fit length
  • Ground wire
  • Speaker wire (optional – you can buy separately also)
  • Crimp ring terminals for the positive & negative power wires
  • Good quality fuse holder + fuse
  • Zip ties (not a necessity but highly recommended)

You need to try to anticipate having long enough wiring for your vehicle plus a small amount of extra length if possible. That means a long enough power cable to reach from the battery positive terminal and fuse holder to the amplifier along with the additional length that comes from bends and curves. Typically 18′ (18 feet) in length is enough.

Similarly, the remote wire and RCA cables should be long enough too. 15 or 16 ft in length is often good. Longer wiring is fine and is a little bit of a bonus as it means you can move the amplifier to different mounting locations if necessary.

Wiring that is very short like 12′ is likely to be insufficient (except for amps mounted under a seat) or may barely reach the rear of the vehicle.

I don’t recommend this as a short power wire or RCA cables must be stretched and may be placed under tension in some cases. In that situation, problems will come up with the wiring or amp if it’s continually being pulled on from wiring that’s not long enough.

The best affordable fuse holders

A good quality fuse holder is essentially all you really need. However, there are a few differences that may fit your installation better than others.

Don’t just buy any type without knowing what you’re in for – it can actually make a big difference in how long it takes to install your amp and how difficult it is. It can also make a big difference as to how well it holds up over time due to vibration, heat, and moisture.

10 ga molded amp wiring kit fuse holder exampleFor example, lower-cost fuse holders like those in the picture above are found in many budget amp kits. However, they don’t offer the heat resistance, moisture resistance, and great looks of others I’ll mention below.

If you’re tight on money, however, they’re ok as they get the job done and most have good electrical contact. Be aware though that molded fuse holders are normally only rated for smaller amps and use 10 gauge wiring.

They’re not suitable for larger power demands.ANL vs AGU car amp fuseholder comparison imageANL (rectangular, left) and AGU (rounded, right) fuse holders are great and allow you to easily see the fuse element in case it blows. However, I recommend the AGU holder style more as they’re easier to install and typically are moisture and dirt resistant. Also, they look great!

Rectangular fuse holders and round glass-type fuse holders are nice and have a larger conductive area for current to pass through.

Both are great, but the cylindrical type (AGU) holders are a bit easier to use and install as they’re more compact.  Additionally, they tend to be more resistant to moisture and dirt entering them.

Avoid getting scammed! A warning about wire quality

Image of an angry man upset about cheap wiring kit

Unfortunately, you can’t trust advertising. There are several gimmicks being used today by wiring kit companies that mislead buyers and will cause you to think you’re getting a great deal when you’re not.

These days some companies are using false advertising and oversized power wire insulation to trick you into believing you’re a larger wire and better deal than you really are.

For example, some amp kits sold as 8 gauge are in fact actually closer to 10 gauge or smaller wire. From the outside, it appears fine and legitimate.

However, after stripping the insulation off you can see that the wire itself is smaller than expected (if you know what to look for) and the insulation is much larger than necessary.

It’s a gimmick used to fool the eyes as the wiring appears bigger than it actually is when viewed through the insulation.

Wiring sizes are standardized according to the American Wire Gauge (AWG) chart. This means that wire manufactured and sold should be labeled according to this chart. If it isn’t you’re at the mercy of anyone who wants to make money off of you and trick you into buying less for your hard-earned dollar.

The same applies to speaker wire as well.

Image of fake vs true 4 gauge amp power wireA comparison of true 4 AWG wire (center) versus 2 fakes. Notice the size of the wire conductors vs. the insulation. It’s a gimmick used by many lesser brand amp wire kits and you’ve got to be careful when buying. You’ll get scammed and you’re not getting what you paid for!

Pure copper vs. copper-coated aluminum wire

Maybe you’ve head about the rising price of copper in the news over the last few years. You might not be aware but many products with braided wire like amp and speaker wire are no longer produced with pure copper.

A lower-cost version is being sold often without the public being aware.

Copper clad aluminum vs copper speaker wire illustrated diagram

Copper-coated aluminum (CCA) wiring is produced by using a combination of copper over aluminum wire in order to reduce cost. The problem is that aluminum isn’t is good of a conductor for electrical current as copper is and it’s not always a good choice for high-current wiring.

Generally speaking, for the average installation it’s ok, but the main issue I have is that people aren’t always aware because sometimes it is hidden in small print or not disclosed at all!

So, unless you have specific reasons for buying it or just truly want pure copper wire, I wouldn’t worry too much about this issue. Do be aware that aluminum wire can less flexible to a degree than pure copper wire but it also depends greatly on the brand quality.

If you prefer to buy pure copper wire be sure to look closely to avoid being misled by the labeling and advertisements used.

I prefer pure copper wire personally and recommend it for installations which will deliver very large amounts of power and the current drawn will be very high. Again, for the average, moderate-volume system it’s not as necessary.

Ring terminals

rimp ring and lug terminal examplesRing terminals are included in some amplifier kits and are fantastic for making a solid and reliable power connection for both the positive and negative wiring cables.

In the photos above, the gold-plated crimp ring terminals are the most common and, while they’re not expensive, they’re very good in my experience. 

You can use a decent crimp tool, vise grip pliers, or possibly other tools to crimp them securely after stripping about 3/8-1/2″ of insulation off of the wire. You can use them to connect to available bolt studs if available for a great way to connect your amp’s power wiring.

Note that in the pictures above, the terminals on the right are called “crimp lug” terminals, and generally speaking, they should be avoided unless you have the proper tools to use them.

“Lug” crimp connectors are much harder to crimp and require special tools to securely attach to wire, unlike standard ring terminals. Don’t waste your time with them.

What size amp kit do I need?

Best amp wiring kit featured image

Remember to always be sure the wire size you’re planning to buy will fit the amp terminals!

If not, you’ll have a difficult time getting the wiring to fasten securely on the amp. There won’t be sufficient room for the wire strands and wire can come free and potentially cause a short circuit.

Quick tip: If you’re unsure of what wire size your amp can hold, and if it doesn’t specify in the specifications, likely it can hold up to 8 gauge wire.

That’s one of the most common sizes for average amplifiers sold today.

When in doubt, remember that many amps use a maximum size of 8 or 4 gauge wire. Using a larger wire than an amp requires is actually a waste of money and it can be harder to deal with.

One exception is moving up from a 10 AWG kit to an 8 AWG kit, as they’re priced similarly these days and unfortunately, many kits sold as “10 gauge” are much smaller wiring as I warned you about earlier.

How to figure out the amp wiring kit gauge you need

To estimate what gauge of amp wire that you need to use these steps:

  1. Calculate: (Amp power (RMS) / efficiency) / 13.8V = Current draw in Amps
  2. Select a wire size based on the chart below

What we’re doing is calculating how much current we’re drawing based on the maximum power the amp can use minus losses. All car amps have an efficiency rating which is because some electrical current is wasted and turned into heat.

For class A/B amps, efficiency is around 65%. For class D amps it’s closer to 90%.

Max. Current
(Amps)
Wire Gauge(AWG)
100
2
80
4
46
8
33
10

We can do a little bit of math to get a rough estimate in order to choose a safe size. Remember to always use the Root Mean Square (RMS) ratings as those are the actual, realistic power ratings that an amp should be able to actually provide to speakers. Exaggerated or misleading specs will cause you to greatly over-estimate the amount of current (Amperes, or “Amps”) an amplifier will draw.

Example #1:

For a class A/B (standard) 4-channel amp rated at 75W per channel we can find:

  1. Total max. power: 75W x 4 = 300W
  2. (300W  / 0.65) / 13.8V = 33.4 A (accounting for about 65% efficiency)

Therefore we can use an 10 AWG wire kit, or step up to 8 AWG wire if we like.

Example #2:

For a 4-channel class D amp with 75W per channel we can find:

  1. Total max. power: 75W x 4 = 300W
  2. (300W / .90) / 13.8V = 24.2A (accounting for about 90% efficiency)

Therefore we would use an 10AWG wire kit (or 8 gauge, if we like).

As you can see, a class D amplifier uses less electrical current and can often use a smaller power wire size (more than 10A in this case!).

★ 5 excellent amp wiring kits for the money★

Our top picks

ImageProductDetails
sample-table__image★ Our #1 Pick ★KnuKonceptz KCA 4 Gauge
  • Fantastic 4 ga. kit for the money! Quality wire & more for under $40
  • 18 ft ultra-flex wire, moisture resistant fuseholder, oxygen free ground wire
  • 20' speaker wire and twisted pair 17' oxygen free RCAs
Check on Amazon
sample-table__imageNVX XKIT42 4 Gauge
  • 100% oxygen free, high-flex copper wire. Shielded RCA cables
  • Corrosion & damage-resistent insulation
  • Includes pro quality fuseholder, lug connectors, high-quality speaker wire
Check on Amazon
sample-table__imagePro QualityStinger SK6681 8 Gauge
  • High-end wiring quality for when you want the best
  • 100% oxygen free fine standed copper, high-current ground wire & lug, shielded RCA cables
  • Includes zip ties, full connectors, and pro level fuse holder and more
Check on Amazon
sample-table__image$25 and under!Belva BAK82 8 Gauge
  • Affordable, high-value complete wiring kit under $25
  • Everything you need: RCAs, speaker wire, power and ground, zip ties, and more
  • Includes high-current, moisture-resistant fuse holder
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sample-table__imageStinger SK46101 10 Gauge
  • High-quality 10 ga kit that won't let you down. Easy to install and reliable
  • 100% oxygen free fine standed copper, true-sized power and ground with plated ground terminal
  • Includes high-fidelity, high-flex RCAs, zip ties, and more
Check on Amazon

> Best 4 gauge kits <

1. KNU Conceptz KCA-K4 4 gauge amp wiring kit – Excellence on a budget!

KNU Conceptz KCA-K4 4 gauge amp wiring kit image

With the KNU Konceptz KCA-K4 amp kit, you get what you need to kick ass musically. Unlike other amp kits, however, it’s not outrageously priced despite the great quality you get.

This is some great wiring in a 4 gauge kit for under $40!

This is a wiring kit with an easy-to-install AGU fuse holder and some seriously good wiring. The positive and negative power wires are made with copper-coated aluminum (CCA) wiring to keep costs down but still remain highly flexible and installer-friendly.

KNU Conceptz KCA-K4 4 gauge amp wiring kit fuse holer imageThe AGU fuse holder is simple to install as it just requires stripping off a small amount of the positive power cable then inserting it into the fuse holder receptacle before tightening the fastening screw. Both the wire insulation and fuse holder plastic housing look distinctively different and will really set your installation apart.

KNU Conceptz KCA-K4 4 gauge amp wiring kit RCA cables imageYou’ll also get some great twisted-pair RCA cables with gold-plated contacts and durable insulation. They’re also flexible and work really well for installations.

The speaker wire kicks ass and I wasn’t expecting such a high-quality roll of speaker wire to be included. It feels and works great, and it’s much better than the typical 18 AWG wire most kits would include.

This affordable, quality kit includes:

  • 18 Feet 4 Gauge Ultra Flex Blue Power Wire
  • 3 Feet 4 Gauge Ultra Flex Black Ground Wire
  • One inline fuse holder with 80A AGU Fuse
  • One 5 Meter black RCA Cable with Built in Turn On lead
  • 20 Feet Clear 14 Gauge CCA Speaker Wire
  • 2 Gold Plated 4 Gauge Ring Terminals, 2 Gold Plated 4 Gauge Spade Terminals
  • Wire ties

Listen, guys, you’re going to be hard-pressed to get a better kit for the money. Want a great kit but need to keep costs down?

This is a fantastic choice.

Take my advice and head on over to see the current price and wonderful reviews at Amazon now.

2. NVX XKIT42 100% copper 4-gauge install kit – Professional quality wiring you can afford.

NVX XKIT42 4 ga amp wiring kit

The NVX XKIT42 really hits a sweet spot between spending way too much for a pro-level 4 gauge amp wiring kit in your local car stereo shop or retail store and getting a budget-priced kit.

I say that because despite it featuring truly high-end 100% copper stranded wire that’s coated in silver, it still sells for a price that’s far less than the $100 or more I’ve seen on other similar kits.

It features:

  • 20 ft. (6.1m) Frosted Blue 4 gauge main power wire with seamless crimp ring terminal
  • 3 ft. (.91m) Frosted Black 4 gauge main ground wire with seamless crimp ring terminal
  • 20 ft. (6.1m) Clear 18 gauge remote lead wire
  • 40 ft. (12.2m)) Frosted Black/Blue 16 gauge speaker wire
  • One 16 ft. (5m) 2-channel twisted construction RCA Interconnect Cable
  • 1 ANL/Mini-ANL fuse holder with 100 amp Mini-ANL fuse
  • 1 black rubber firewall grommet
  • Two 4 gauge nickel-plated spade terminals
  • Four 18 Gauge Spade terminal
  • Two 18 Gauge Red butt connectors
  • Four 16 gauge quick disconnects
  • Five 16 Gauge Nickel Plated spade terminals
  • 10 6″ black zip ties

The wire is some of the most flexible wire around and it’s rare to find silver-coated wire anywhere. I was honestly surprised to have run across this kit, as I hadn’t expected to find something so good that’s not overpriced.

If you’re looking for one of the best money can buy (in this case around $60 dollars) that looks fantastic this is the kit you need!

Head over to check it out and find the best price over at Amazon.

> Best 8 gauge kits <

Stinger SK6681 8 AWG complete amplifier wiring kit – 100% oxygen-free copper in a kit that’s hard to top. A step above the others.

Stinger SK6681 8 AWG amp wiring kit image (2)

Stinger has always been known for its great installation wire, stereo installation kits, and a variety of aftermarket items that are always some of the best you can buy. The SK6681 is no exception.

What really sets is apart from the others is not only how flexible the wire is (100% oxygen-free copper, with fine conductors for maximum installation ease and power conduction) but how wonderful it looks.

Much like the larger NVX XKIT42 it features stretch wire loom for a clean installation and protection in the engine compartment as well as a compact but high-conducting fuse holder.

All power wiring is “tru-spec” and meets the AWG gauge chart sizing as advertised – no misleading wire sizing here. Conductors on the connectors are tinned for corrosion resistance.

RCA cables are shielded and audiophile-grade and are 17 ft in length to accommodate nearly all installations.

The included fuse holder is water-resistant as well!

The SK6681 comes with:

  • 17 ft. of 8 gauge matte blue hyper-twist power wire
  • 3 ft. of 8 gauge Matte silver hyper-twist ground wire
  • 17 ft. of 18 gauge Blue turn-on wire
  • 17 ft. 6000 Series RCA interconnects
  • 30 ft. 16 Gauge speaker wire
  • Mini-ANL style fuse holder
  • 70 amp Mini-ANL fuse
  • Pre-terminated ends
  • Mesh wire loom
  • Stinger metal badge
  • Includes installation accessories (wire ties, crimp terminals, etc.)

I wouldn’t pass it up if I were you and I was looking for an 8 AWG wiring kit I could afford without having to settle for a CCA wire type kit. Even better, it sells for around $50 or so!

Your dream system is waiting for you! It only takes a few seconds to find out why it's one of the best selling amp kits at Amazon today.

Belva BAK8 complete 8 gauge amplifier wiring kit – Great-looking & high-performance with a fantastic budget price!

Product image of the Belva BAK82 amplifier wiring kitThis kit by Belva is a great cost-cutting way to get good amp performance in your ride. It’s designed for amplified systems up to 500W and comes with premium Powerflex power and ground wire that bends easily for making installation less of a hassle than lesser brands.

Closeup of fuseholder from the Belva BAK82 amp wiring kitYou’ll get a great-looking and water-resistant fuse holder as well. Thanks to the design installation is simple and requires no additional crimp contacts. Just take it apart, strip your power wire, and insert it into the contact points. Tighten the screws and you’ve got a great and reliable power source!

This is a CCA wire kit, but unlike others, the Belva CCA wire is made from 30% copper wire while competitors use only 10%! The included RCA cables feature a helical-twisted construction to minimize noise and interference and are a wonderful 17 ft in length!

The power & speaker wiring included feature a very durable – but flexible – jacket, making them a pleasure to install. The fine wiring conductor count also is a step above lesser brands. You’re going to like it a lot!

For around close to only $20 dollars you’ll get:

  • 17 ft. (5.2 meters) Red 8 gauge power wire
  • 3 ft. (.91 meters) Black 8 gauge ground wire
  • 17 ft. (5.2 meters) Gray 18 gauge remote lead wire
  • 17 ft. (5.2 meters) Helical Twist 2-channel RCA interconnect cable
  • 20 ft. (6.1 meters) Speaker cable
  • One In-line Mini-ANL Fuse Holder with a 60 amp Mini-ANL fuse
  • One black rubber firewall grommet
  • 1 each 8 Gauge Blue & black chrome-plated ring terminals
  • Three 18 Gauge Blue Spade terminals
  • Two 18 Gauge Black Spade terminals
  • One 18 Gauge Red butt connector
  • Ten 4″ Black zip ties

This isn’t the “el cheapo” kit like so many amateurs buy – but unlike them, you’re a smart shopper so you’ll be getting a real 8 gauge wire rather than paying the same money for 10 gauge wire!

Ready to get your system going and enjoy the music you love without limitations?

Take the next step and  check out the fantastic Belva 8 ga. kit at Amazon today.

> Best 10 gauge kit <

Stinger SK46101 – A no-nonsense 100% copper amp wiring kit that looks great. Excellent RCA cables, too!

For this size of amp wiring, I’m going to recommend just one as there are so many amp kits sold as “10 gauge” that are in fact rip-off in nature. But primarily you can buy an 8 AWG amp wiring kit for nearly the same money as a good 10 AWG kit, so it’s something to consider when shopping.

Stigner SK46101 10 gauge amp wiring kit image full

The SK46101 is a kit I really like. One major reason is that during installations, amp wiring with a pre-installed fuse holder like this one made the installation process that much easier and faster. It uses a standard automotive fuse to protect the positive wire from shorts. Included is everything else you need. This is real 100% oxygen-free copper wiring here, my friend!

Not only that, but quality ring terminals are included for a really tight install and no power-robbing poor connections on the battery and ground wiring.

The wiring features attractive matte insulation but what I really love about it is the RCA cables which feature shielded twisted-pair wiring for reduced noise and excellent sound conductivity. Besides, they just look great!

For close to $35 you’ll get:

  • A 17Ft. 4000 Series 2 Channel Audio Interconnect
  • 18 Ft. Matte Red Hyper-Twist 8GA Power Wire
  • 3 Ft. Matte Black Hyper-Twist 8GA Ground Wire
  • 17 Ft. Matte Blue 18GA Remote Turn-On Wire
  • SPD5101 AGU Fuse Holder
  • 60 Amp AGU Fuse
  • 8GA Crimp Ring Terminals Pre-Installed
  • 16GA Blue Butt Connector
  • 8GA Snap In Protective firewall grommet
  • Self Drilling Mounting Screws
  • (10) 7” Wire Ties

Not only that, but the power connections are pre-terminated so that’s even less work you have to do!

I totally understand how it feels to be strapped for cash – that’s totally ok!

You don’t have to settle for less. Head over and  get one of the best values for your dollar at Amazon right now. You won’t regret it!

Final thoughts on amp kits

Ultimately it’s up to you to decide how much money you’re willing to spend, but I strongly encourage you to be careful and pick up one of the kits I’ve listed above. They’re good, reputable kits and you won’t get scammed with buying something only to get extremely disappointed once you get it home & check it out.

I don’t want that to happen to you.

Remember the following:

  • copper-coated aluminum (CCA) wiring is the less-expensive version of today’s amplifier power cables in wiring kits
  • Real 100% copper wiring kits cost more and can handle more electrical current, but for typical installations, they’re not totally necessary. (mainly for very-high power systems and for people who demand the best quality)
  • Many budget amp wiring kits are NOT true-spec wire: they lie about the wire size and don’t follow the American Wire Gauge (AWG) standards as reputable brands do

When in doubt about a kit’s quality, don’t buy it! You’re very likely to be disappointed and may have to return your kit for a better one.

Spend a few more dollars for a kit you can count on to avoid problems when it comes time to install your system.

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!

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.