How To Connect A Car Amp To A Home Stereo (With Diagrams)

How to connect a car amp to home stereo featured image

Using a car amp…at home? It’s not such a crazy idea after all! While it’s true that it’s not super easy, it’s really not all that hard and you can do it.

In this article, I’ll explain how to connect a car amp to a home stereo with clear diagrams anyone can understand. I’ll also show you all the little things you need to know before you try so you avoid disappointment & headaches.

Contents

First things first: Can a car amplifier be used at home?

Can a car amp be used at home man thinking

The good news is that YES, one way or another, you can definitely connect a car amp to a home stereo.

However, since car amps use a different power source the single biggest challenge is getting enough power to them. They also use a remote-on wire to turn the amp on & off so it doesn’t draw power and kill your battery when installed in a car.

Fortunately, these (and other) problems are fairly easy to deal with. Here’s a list of what you’ll run into when using a car amp at home:

  • Signal inputs: Not all home stereos have RCA line-level jacks, so this may require a workaround to connect to your amp’s audio inputs. Some amps make this pretty easy, however. (This isn’t much of a problem as you’ll see from my diagrams below)
  • Power source: Unlike home stereos that are powered from alternating current (AC), car amps work from a +12V direct current (DC) supply. You’ll need a +12V AC-DC power supply with enough current to run the amp. Not just any AC/DC 12V adapter will do as you’ll see later.
  • Turning the amp on/off: This is actually really easy! You can simply disconnect your DC power supply and let the amp shut off or use a simple switch to turn the amp on and off. I’ll show you how to wire the car amp so it can turn on.

The bad news is that unless you have the parts you need already, you’ll probably have to spend a little bit of money to get it working well.  The good news is that most of what you need can be found and bought new or used but you may need to order some online.

Sadly, retail stores are usually poorly stocked when it comes to power supplies that you can use for a car amp indoors. You’ll have much better luck online at places like Amazon or electronic parts suppliers.

How to use car amp with a home stereo + diagram

How to connect a car amp to a home stereo diagram

The way you’ll connect your car amp depends on both your home stereo and your car amp’s features as I mentioned earlier. You’ll end up with one of 3 situations:

  1. Home stereo with no RCA output jacks + car amp with speaker level inputs: It’s actually fairly common for home stereos and home theater receivers to have no full-range RCA jacks you can connect to the amp. In this case, if you’ve got a car amp with speaker level inputs these can be connected to either an unused pair of speaker terminals or alongside speaker terminals in use. The amp’s speaker level inputs will scale down the speaker inputs to a low signal it can use.
  2. Home stereo with no RCA output jacks + car amp with RCA jack inputs only: In this case, you’ll have no choice but to use a line level converter commonly used for car audio. Just like in #1 above, these are connected just like speakers to unused speaker terminals or alongside an existing speaker set. This will drop the signal down to a very low level that’s used by the amp’s RCA inputs. Note: I strongly recommend getting a decent quality model converter with adjustable outputs for best results.
  3. Home stereo with full range RCA output jacks + car amp: This is the easiest way by far, but not all home stereos have full-range RCA output jacks. Some only have subwoofer RCA output jacks which are bass-only outputs. Full-range RCA output jacks can be connected directly to the car amp’s RCA inputs.

How to connect the remote-on wire on a car amp

How to connect remote wire on car amp used in home diagram

In all cases, you’ll also need to wire the amp with power and a remote-on wire so it can turn on. You can do this one of several ways:

  • Jumper the remote on terminal:  When wiring the power and ground 12V connections, you can use a small jumper wire from the +12V terminal to the remote terminal so it’s on any time the amp has power.
  • Just a jumper wire + switch: Basically the same, but you can also duplicate how a car stereo’s remote on wire works by using a simple inline switch on the remote wire to turn it on/off yourself.

If you’re using a switch you can leave the AC/DC power supply plugged in if you like. When the amp’s remote wire loses its +12V signal, the amp will switch off internally and draw zero power.

Example of line level converter with remote wire output Axxess AX-ADCT2

QUICK TIP: To make things even easier, you can use a line level converter with a built-in remote wire output feature which will automatically turn the amp on or off with the speaker input signal.

Note that these do need a power and ground connection.

What is a line level/RCA converter and how do they work?

Image showing examples of line level RCA converters

Shown here are two quality examples of line level/RCA speaker level converters: a 2 channel RCA output model and a 4 channel RCA output model.

Line level converters (also called RCA speaker level adapters) are small electronic devices that connect to speaker outputs from an amp or receiver and scale down the higher-voltage signal to a low level (“line level”). The outputs are RCA jacks which can then be connected to an amplifier or subwoofer with RCA jacks.

They’re extremely handy in the car stereo world because they make it possible to connect a stereo without RCA outputs to any amplifier or powered subwoofer. We can also use them for home stereos, too.

How much do line level converters cost?

While you can get the el-cheapo ones for under $10, I don’t recommend those. Expect to spend around $15-25 or so for a good one. No need to spend too much these days as there are lots of good values out there.

What voltage & size DC power supply do I need for a car amp?

Example of how to estimate car amp current used

You can get a rough estimate of the maximum amount of electrical current you’ll need for a car amp using its maximum RMS power as shown here. However, if you’re not using an amp to its full capability you can get buy with a smaller (and less expensive) power supply.

What voltage does a car amp need?

Car amplifiers, when installed in a vehicle, work off of a voltage range as the engine runs. Although we say cars & trucks use a 12V supply, in reality, a car amp is designed to work from somewhere around 11V to 14.4V or so as the alternator in your vehicle raises or lowers it’s output while charging the battery.

Therefore you can use a power supply with a DC output similar to this, but I recommend 12V to 13.8V. Most power supplies you can buy are one of these.

What size power supply do I need?

Car amp DC power supply examples

You’ll need a power supply with a decent amperage (A) rating. Regular wall adapters won’t work as they’re very weak (0.5 to 1 amps or so). You can find 5A supplies for under $15 depending on where you shop. Desktop computer “ATX” power supplies are affordable and available in power ranges up to 500W or more. They’re easy to find but need a certain wiring connection in order to turn on.

In order to figure out how big of a DC power supply you need, you might want to calculate roughly the amount of current your amp will draw at full power. Once we know that, we can take into account wasted power that all amps use up and come up with a fairly accurate number.

Just so you know, class D car amplifiers are more efficient and therefore waste less power (and draw less current) than standard class A/B amps.

If you’re not sure what class your amp is, if it’s a class D amp it’s usually stated on the box or the amp itself. Class A/B amps often don’t state it anywhere. (Many new amps are class D so I wanted to take that into account)

Estimating amp current

You can estimate amp current based on the maximum RMS power of the amp. Don’t use “peak” or “maximum” watts as these don’t reflect the actual continuous power a car amp puts out.

As class D car amps are around 85% efficient and A/B amps are around 65% or so efficient we can use that to estimate the total current an amp would need.

Class D amp example:

Estimating the current used by a 50W RMS x 4 amp, all 4 channels used:

  1. 4 x 50W = 200W total. (200W/12V) = 16.7A.
  2. Take into account power waste: 16.7A/.85 = 19.6A
Class A/B amp example:

Estimating the current used by a 150W RMS x 2 amp, both channels used:

  1. 2 x 150W = 300W total. (300W/12V) = 25A.
  2. Take into account power waste: 25A/.65 = 38.4A

As you can see, to run a car amp at full power you’ll need a pretty big power supply! However, the good news is that it’s only if you really want to drive the amp at full capacity. For lower-power, casual listening, we can get by with a smaller (and thankfully, cheaper) power supply.

Realistic power ratings you’ll need

For just listening to music with decent volume, I recommend at least a 2.5A supply for small amps (under 50W/channel). For 4 channels or higher power ones, I’d get a 5 amp or bigger. If you’d like to have more power, consider getting 15A or above.

You can find a 5A supply for under $15-$20 if you shop carefully. 10A and 15A supplies are fairly popular so they’re usually really affordable, too. However, when it comes to much bigger supplies that will let you drive a subwoofer with heavy bass, for example, those can be expensive: $100 and above.

Connecting 2 RCA stereo outputs to a 4 channel amp

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

What if you’ve got a 4 channel amp? No problem! You’ll still use the same methods shown earlier but you’ll need to jumper either the speaker level inputs or the RCA inputs using “Y” connections to get a signal to the rear channels too.

Most car amps with front & rear speaker level inputs can be wired to 2 speaker input pairs as shown in the diagram here. When using RCA connections, you can pick up a pair of inexpensive female-to-male Y adapters to split the signal from 2 into 4 connections. (Don’t spend too much on Y adapters as you can use a decent pair of cheap ones just fine)

QUICK TIP: Some car amps have a 2/4 channel input switch built in for this purpose. In that case, setting it to the “2ch” position will supply a signal to all 4 channels. For some amps this only applies to the RCA inputs so be sure to check your owner’s manual.

Can I use 8 ohm speakers with a car amp?

4 ohm vs 8 ohm speaker power comparison graph

This graph shows what happens when you use an 8 ohm speaker in the place of a 4 ohm one. The 8 ohm speaker will work – however, it comes with a price. Since the 8 ohm speaker isn’t matched to the 4 ohm car amp, it can only receive up to 1/2 the power output and has a lower maximum volume than a 4 ohm speaker would.

Using 8 ohm home speakers in place of 4 ohm ones with your car amp won’t hurt anything. There’s a catch, however. They’ll only develop 1/2 the power of a 4 ohm speaker meaning lower maximum volume is possible.

For example, if you were to use some home stereo 8 ohm speakers instead of 4 ohm speakers, you’d notice the volume would be a bit lower than when using 4 ohm ones. That’s because a speaker needs more and more power output to increase the volume more and more; also 8 ohm speakers allow only 1/2 the same amount of electrical current to flow vs 4 ohms.

Car amplifiers & car head units don’t have a high voltage supply like home stereos and home amplifiers do. That means they’re designed to use lower impedance (lower resistance) speakers to develop the same amount of power by letting more current flow.

As long as you’re aware of this it’s ok, because they’ll still sound and play fine – you just can’t get the same power and as much volume when you crank it up vs using 4 ohm speakers.

I have a hum (ground loop noise) from the amp. What can I do?

Example of an RCA ground loop isolator

Example of a ground loop isolator you can use to break the ground conductor connection in RCA cables to eliminate ground loop noise.

Unfortunately, noise is a problem with car amps despite them being designed to prevent it. It’s also true that home stereos and amps are known to sometimes create “ground loops” between different electronic components via the RCA cables.

Ground loop noise happens when there’s a slightly different potential (electrical voltage point) between the grounds of an amp, stereo, and other components. Despite everything you try, sometimes it’s nearly impossible to eliminate.

In that case, you can use a ground loop isolator to connect inline in the RCA cables. This usually does the trick. Note that you shouldn’t try to get the cheapest you find because they can negatively affect sound quality.

You can find a good one for $10-$25 or above depending on the brand and features. The good news is that they’re super easy to use: just connect them to the RCA cables and you’re done!

More great articles you’ll love

There’s lots more great stuff to see! Here are some excellent articles that have helped many others, too:

Let me know what you think!

Have questions or comments? Just let me know below! You can also contact me directly here.

How To Connect A Subwoofer To An Old Amplifier Or Vintage Receiver

How to connect a subwoofer to old amplifier or vintage receiver featured image

Got a vintage amplifier or receiver? When it comes time to add some great low-end bass you might be scratching your head wondering how – and if – you can add a subwoofer. 

The great news is that there are several ways to connect a subwoofer to an old amplifier or vintage receiver.

Even better, it won’t cost a lot, either! Read on and I’ll share with you 3 ways to connect a subwoofer along with clear subwoofer diagrams anyone can understand.

Contents

Home stereo subwoofers explained

Passive vs active home subwoofers diagram

Comparing passive (non-powered) vs active (powered) home stereo subwoofers. Powered subwoofers have an internal amplifier and one or more signal input options: speaker inputs, RCA input(s), and in some cases, digital audio inputs.

There are two kinds of home stereo subwoofers: powered (“active”) and non-powered (“passive”).

  • Powered subwoofers use a low-signal signal which is boosted greatly using the built-in speaker amplifier, power supply, and crossover. These types are one of the most common and in many cases use an RCA type input jack to connect to the receiver for sound.
  • Passive (non-powered) subwoofers are simply a subwoofer speaker inside the bass enclosure which is directly wired to the speaker terminals or a passive bass crossover inside. These types are less common.

How does a subwoofer work?

An amplifier boosts the low-level input signal in order to drive the subwoofer’s voice coil with sufficient power and move the speaker cone, producing sound. As the cone moves the air inside of a specially designed enclosure (speaker box) deep bass, contained in the musical input signal, is produced.

They’re designed for only low-end bass and not voice or other musical instrument frequencies.

A powered subwoofer includes an amplifier already inside the subwoofer enclosure. It also has a built-in low-pass crossover to block higher sound frequencies in order to produce clear and great-sounding bass only.

For non-powered subwoofers the problem comes when you connect one to an amplifier or receiver’s outputs without a crossover – it sounds terrible!

Old amplifiers and vintage receivers vs new receivers

Unlike older amplifiers, more modern home stereos and especially home theater receivers have a subwoofer output jack (or pair of jacks) dedicated to this bass signal a subwoofer uses to create sound. This is usually from stereo music signals or the subwoofer (“.1”) channel sound in multi-channel surround sound material such as Dolby Digital or DTS.

For example, you may see terms like “5.1” or “2.1” speaker systems or surround sound audio listed for movies. In this case, the first number represents the number of main speakers. The “.1” is used to represent a sound channel limited to only bass for subwoofer use.

Older amplifiers and receivers don’t provide a subwoofer output so we’ll need to connect a subwoofer by other ways.

Powered subwoofer inputs & controls to know

Powered subwoofer example with inputs and controls labeled

Shown is an example of a powered subwoofer’s rear panel with 2 kinds of inputs: speaker inputs and RCA (low level) input jacks. Note that not all subwoofers offer speaker level inputs, meaning if yours doesn’t have them it’s a bit harder to connect the bass signal input.

Powered subwoofers usually have a few different inputs and controls. It always depends on the particular brand and model you buy.

Here’s what you’ll usually find on most:

  • Power input (AC outlet power)
  • On/off switch
  • RCA input jack or a pair of jacks
  • Subwoofer crossover adjustment
  • Subwoofer level adjustment know (the amplifier’s signal boost level)

In most cases, a subwoofer input jack, if you had one on a receiver, is a “mono” (monaural, 2 stereo channels combined into one) signal you connect with a single RCA cable.

Receiver subwoofer output jack example

Shown: What a receiver with a subwoofer output jack looks like as found on many newer receivers. These connect to the RCA input jack on the subwoofer, if present.

Of course, if you’re reading this it’s because you don’t have a receiver with a subwoofer output. In fact, some of the information you’ll find right now on the internet says that you have to buy another subwoofer if you don’t have a receiver with an output jack. That’s simply not true.

Subwoofers with speaker level inputs are great to have for exactly this reason as you can connect them directly to an older amplifier or vintage receiver’s speaker outputs.

Even if you buy (or already own) a subwoofer without speaker level inputs, it’s ok – there’s another way to basically connect it essentially the same way!

Below you’ll find a diagram showing how to connect an old amplifier or receiver without a subwoofer output easily.

Diagram & examples: Connecting a subwoofer to an old amplifier or vintage receiver

Diagram showing how to connect a subwoofer to an old amplifier or vintage receiver

1. Connecting an old amplifier or receiver to a subwoofer with RCA input jacks

Example of a powered subwoofer RCA jacks & RCA Y adapter cable

Left: Example of a powered subwoofer with 2, instead of the typical 1, RCA input jacks. Right: An RCA Y adapter that can be used with a line level converter to connect to a subwoofer with a single RCA input jack.

If you’ve got a subwoofer with 1 or 2 RCA input jacks and no speaker level inputs, here’s a simple and high-quality way to connect it: by using a line level converter.

What is a line level converter and how do they work?

Line level converters (also called RCA speaker level adapters) are small electronic devices that connect to speaker outputs from an amp or receiver and scale down the higher-voltage signal to a low level (“line level”). The outputs are RCA jacks which can then be connected to any amplifier or subwoofer with RCA jacks.

 While you almost never see them used for home stereo systems, they’re extremely handy in the car stereo world because they make it possible to connect a stereo without RCA outputs to any amplifier or powered subwoofer.

Likewise, they can be used for home stereo amps and receivers, too!

Image showing examples of line level RCA converters

Shown here are two examples of line level/RCA speaker level converters: a 2 channel RCA output model and a 4 channel RCA output model.

How much do line level converters cost?

Line level converters vary in price a bit depending on the quality and features, selling around $15-$25 or so in many retail stores and online stores.

How to use a line level converter

To convert speaker level outputs from your amplifier or receiver to RCA jack subwoofer outputs, you’ll connect the provided speaker wire connections (marked by colors and striped) just like you would regular speakers. You then connect RCA cables (or a single cable, depending on your particular one) to your powered subwoofer.

The internal electronics not only scale down the speaker output voltage from a receiver but also help prevent noise from the audio path, too. Most, but not all, speaker level adapters do not need a power source.

If your subwoofer has a single RCA subwoofer input jack, you may want to pick up a “Y” RCA adapter to combine both receiver channels on the output side into a single mono RCA plug.

Subwoofers with 2 (stereo) RCA jack inputs will need a standard stereo male-male RCA cable.

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3. Connecting a subwoofer with speaker level inputs

Example of subwoofer speaker level inputs

A subwoofer with speaker-level inputs is especially easy to connect to your older amplifier or receiver! To do so, just connect to the speaker outputs on the source unit using speaker wire and then to the matching inputs on the subwoofer. You can even power speakers from the amp or receiver at the same time.

If your subwoofer has speaker level inputs built-in you’re in great shape! Just connect them directly to your amplifier or receiver’s speaker outputs, either to unused speaker terminals or at the same time (in parallel) with speakers connected to the receiver.

Just like an off-the-shelf line level RCA converter I mentioned earlier, the subwoofer’s internal electronics will scale down the speaker signals to a much lower line level signal the internal amp can use.

You can still expect very nice sound quality as the signal used is just divided down and isn’t changed. Because speaker level inputs have a very high input impedance (total input resistance), in most cases it won’t hurt to connect them to your receiver or amp at the same speaker wire terminals where speakers are already connected.

To do so, you’ll just connect them in parallel: positive speaker inputs to positive speaker outputs and negative speaker inputs to negative speaker outputs.

Additionally, there’s a low-pass crossover built-in as well to produce great-sounding bass and no unpleasant parts of the music – just pure, low-end bass.

Note: Subwoofers with speaker level inputs and outputs provide a way to easily connect both at the same time. The outputs are internally connected to the input connectors, making it easier to add speakers and the subwoofer to a receiver simultaneously.

3. Connecting an amplifier’s speaker outputs to a passive (non-powered) subwoofer

Example of a passive subwoofer low pass crossover

A passive subwoofer low-pass crossover, unlike an electronic crossover, works using capacitors and inductor coils instead of electronic components to filter out the unwanted higher-frequency sound that would otherwise go to the subwoofer. This lets you power the subwoofer with only a lower bass sound similar to how a powered subwoofer works.

Using a passive (non-powered) subwoofer is definitely not as easy as a powered one. The good news is that it can be done, and relatively easily, too. In fact, it you don’t have to worry about going broke, either, although you will need to do a bit of shopping.

To connect your amplifier or receiver to a non-powered subwoofer as is shown in the diagram above, you’ll need to pick up a low pass crossover that you’ll connect between the amp or receiver and the subwoofer.

These will filter out sounds above the crossover frequency and provide only a nice bass sound to it.

How to choose a subwoofer crossover

Speaker crossovers like the one shown are sold both in a single (one speaker) or dual (2-speaker) models depending on the brand & supplier. They also have to be matched correctly to the impedance (Ohms rating) of the sub.

For example, for an 8 ohm subwoofer, you’ll need to use a crossover designed for 8 ohm speakers. Otherwise, the sound filtering is radically different and won’t sound right since the speaker load will change how the crossover filters the sound quite a lot.

Normally you’d choose one with a low-pass frequency of close to 100Hz or close to that. You may need to shop around to do so.

Where to shop for passive subwoofer crossovers

Speaker crossovers are sold where speaker parts & related components are sold as well as marketplaces like Amazon or Parts Express. Other speaker specialty stores where replacement speaker parts are sold may have them, too.

Stereo vs surround sound receiver subwoofer output comparison

Stereo vs surround sound receiver differences diagram

Unlike older or standard stereo receivers, surround sound receivers have a unique output that comes from the surround sound movie or music source. However, in regular stereo listening mode, they act the same as regular receivers.

Just as a side note, one thing to be aware of is that when you connect a subwoofer to an old amplifier or receiver you won’t be able to get the separate dedicated bass sound channel (.1 channel) like you can with a surround sound receiver. 

Those are able to extract the dedicated bass sound from a DVD or other media and route it to the subwoofer output jack. On the other hand, it might not even be a problem.

Did you know? The surround sound receiver “LFE” (low-frequency) output is considered optional – hence the “.1” name. 

Surround sound receivers and amplifiers are designed so that you can play nearly all the sound through the main speakers if needed.

In some cases, for example, some movies and music use the bass channel to really draw you into the experience. Using a receiver without that output means you can’t get the same effect, but that’s only for surround sound mode.

The good news is that in stereo mode, both new and old receivers & amps have very similar subwoofer behavior when connected as you’ve seen here. In other words, you probably won’t really miss it if you’re using an older receiver or amp.

That’s just something to be aware of in case you’ve considered upgrading at some point.

More articles with speakers, speaker wiring, and diagrams to help

I’ve got some other great info to help you learn more and get your system going:

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Please feel free to leave a comment or question below – I’d love to help, and it’s appreciated. Note: please provide specific information like brand & model numbers, speaker ohms, and so forth so I can best help you.

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How To Connect A Subwoofer To A Receiver Without A Subwoofer Output

How to connect subwoofer to receiver without subwoofer output featured image

So your receiver doesn’t have a subwoofer output. You’re probably wondering what the heck you can do about it, and you might be worried if you’ll have to spend a lot of money for either a new receiver, subwoofer, or both!

I’ve got great news – there are several simple ways to connect a subwoofer to a receiver without a subwoofer output.

Read on and I’ll show you several options along with easy and clear diagrams to help. There’s no need to throw away your old receiver or break the bank!

Contents

Home stereo subwoofers explained

Passive vs active home subwoofers diagram

Comparison of non-powered (passive) vs powered (active) home stereo subwoofer enclosures.

Home stereo subwoofers are available in two different types: powered (“active”) and non-powered (“passive”).

  • Powered subwoofers use a low-signal signal which is boosted greatly using the built-in speaker amplifier, power supply, and crossover. These types are one of the most common and in many cases use an RCA type input jack to connect to the receiver for sound.
  • Passive (non-powered) subwoofers are simply a subwoofer speaker inside the bass enclosure which is directly wired to the speaker terminals or a passive bass crossover inside. These types are less common.

How a subwoofer produces bass

The subwoofer works by resting inside of an enclosure designed for it and to produce deep bass when playing music limited to low-end bass sounds.

In order to produce clean-sounding bass without vocals or other sounds a subwoofer can’t properly produce, a low-pass crossover is used to allow only bass frequencies to pass & be produced. The problem comes when you try to connect a subwoofer to a signal without a crossover – it sounds terrible!

The subwoofer output jack on a receiver is normally limited to passing bass only, either from stereo music production or from the “.1” subwoofer channel (dedicated subwoofer music content) of a surround sound system.

For example, when you hear references to “5.1” or “2.1” speaker systems or surround sound audio for movies, the first number represents the number of main speakers. The “.1” is used to represent a sound channel limited to only bass for optional subwoofer use.

Powered subwoofer inputs & controls you may (or may not) have

Powered subwoofer example with inputs and controls labeled

Example of a powered subwoofer with 2 types of signal inputs (speaker level and RCA jacks) along with sound controls. Note: Not all subwoofers have speaker level inputs, which makes it a problem connecting them to a receiver without a subwoofer output.

Powered subwoofers usually have several inputs and controls, but it always depends on the brand and model. Here’s an example of what you’ll usually find:

  • Power input (AC outlet power)
  • On/off switch
  • RCA input jack or a pair of jacks
  • Subwoofer crossover adjustment
  • Subwoofer level adjustment know (the amplifier’s boost level)

The subwoofer input jack usually connects to a single mono (monaural, meaning both stereo channels are combined into one) output jack on the receiver.

Receiver subwoofer output jack example

Example of the mono RCA subwoofer output jack found on many home receivers. These connect with a single male to male RCA cable to a powered subwoofer.

Some models also include speaker level inputs, meaning they can be used with any modern or old home stereo receiver without a subwoofer output.

While that’s nice, if yours doesn’t have that feature, ordinarily you’d need to buy a different subwoofer and waste money.

In fact, some of the information you’ll find right now on the internet says that you have to buy another subwoofer if you don’t have a receiver with an output jack. That’s simply not true.

As I mentioned at the beginning of my article there are several ways to work around this problem.

Diagram & examples: Connecting a subwoofer to a receiver without a subwoofer output

Diagram showing how to connect a subwoofer to receiver with no subwoofer output

1. Connecting a receiver to a subwoofer with RCA input jacks

Example of a powered subwoofer RCA jacks & RCA Y adapter cable

Left: Example of a powered subwoofer with 2, instead of the typical 1, RCA input jacks. Right: An RCA Y adapter that can be used with a line level converter to connect to a subwoofer with a single RCA input jack.

For subwoofers with only 1 or more RCA input jacks (no speaker level inputs), a simple way to connect them to a receiver with no subwoofer output is by using a line level converter.

What is a line level converter, and how do they help?

Line level converters are small devices that accept speaker wire connections and scale down the speaker level signal to a low level signal (RCA jack) type output that the subwoofer can accept. They’re extremely handy in the car stereo world because they make it possible to connect a stereo without RCA outputs to any amplifier.

They’re not commonly used for home stereos but still really useful there, too.

Image showing examples of line level RCA converters

Examples of 2 line level converters – both a 2 channel and 4 channel of each. 

How much do line level converters cost?

Line level converters range in price (for a good one) of about $15-$25 each. They’re connected to the speaker leads of a radio, receiver, or amplifier. RCA cables are then connected to the jacks provided. The internal electronics not only scale down the speaker output voltage from a receiver but also help prevent noise from the audio path, too.

If you’re using a subwoofer with a single RCA subwoofer input jack, you may want to pick up a “Y” RCA adapter to combine both receiver channels on the output side into one.

Subwoofers with 2 (stereo) RCA jack inputs, however, will need a standard male-male RCA cable.

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3. Subwoofers with speaker level inputs

Example of subwoofer speaker level inputs

If you own a subwoofer with speaker level inputs you’re in luck! You can connect these directly to your receiver’s speaker outputs, either by themselves (on unused speaker terminals) or at the same time with speakers connected to the receiver.

These subwoofers with this feature contain internal electronics that scale down the speaker signal from the receiver before it reaches the internal amp that powers the sub.

Additionally, there’s a low-pass crossover built in as well to produce great-sounding bass and no unpleasant parts of the music – just pure, low-end bass.

Connect these directly to the receiver just like you would another pair of speakers. 

Note: Subwoofers with speaker level inputs and outputs provide a way to easily connect both at the same time. The outputs are internally connected to the input connectors, making it easier to add speakers and the subwoofer to a receiver simultaneously.

3. Connecting a receiver to a passive (non-powered) subwoofer

Example of a passive subwoofer low pass crossover

Example of a passive subwoofer low-pass crossover. Passive crossovers, unlike electronic crossovers, work using capacitors and inductor coils instead of electronic components.

If you’re wanting to use a non-powered (passive) type of subwoofer, there’s still hope, although it can be a bit harder to find the right parts and set up vs using a powered subwoofer.

To use a non-powered subwoofer, as shown in my diagram above, you’ll use a low-pass subwoofer speaker crossover which is connected between the receiver and the subwoofer enclosure. These filter out higher frequency sounds before they reach the sub to help provide clear & nice-sounding bass only.

How to choose subwoofer crossovers and where to find them

Speaker crossovers such as this are sold both in a single (one speaker) or dual (2-speaker) model, depending on the brand & supplier. They also have to be matched correctly to the impedance (Ohms rating) of the sub.

For example, subwoofer crossovers designed for 8 ohm speakers must be used only with those. Otherwise, the sound filtering is radically different and won’t sound as expected since the speaker load will react differently with the design.

Normally you’d choose one with a low-pass frequency of close to 100Hz or in that range. Speaker crossovers are sold where speaker parts & related components are sold as well as marketplaces like Amazon or Parts Express.

Stereo vs surround sound receiver subwoofer output differences

Stereo vs surround sound receiver differences diagram

Unlike older or standard stereo receivers, surround sound receivers have a unique output that comes from the surround sound movie or music source. However, in regular stereo listening mode, they act the same as regular receivers.

One thing to bear in mind is that when connecting a subwoofer to a receiver without a subwoofer output, you can’t get a separate “.1” bass channel as you can with surround sound receivers.

On the other hand, it may not even be an issue. In fact, the surround sound receiver “LFE” (low-frequency) output is considered optional – hence the “.1” name. There is a drawback, though: for some movies, especially action or other types, the bass channel can be very enjoyable.

Using a receiver without that output means you can’t get the same effect, but that’s only for surround sound mode. The good news is that in stereo mode, both new and old receivers have very similar subwoofer behavior when connected as you’ve seen here.

Just something to be aware of if you’ve ever considered upgrading later.

More helpful speaker info & diagrams

I’ve got lots more information to help you get your sound system going:

Got questions or comments?

Feel free to leave a question or comment below if I can offer help. (Please be specific with information when referring to speakers, receivers, amplifiers, or other parts so I can help you the best I can)

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