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How to Connect a Subwoofer to an Amplifier

I have a confession. The subwoofer has always been one of my favorite home theater speakers.

Yes, I know most people get excited by their impressive front stereo pair. And that all-important center speaker.

And who doesn’t get a thrill when the sound flies around over their heads in their exciting height speakers.

But the subwoofer is the rock upon which all that audio delight is built.

The foundation for movie and music sound. 

While you can get excellent bass from some bookshelf and tower speakers. In my opinion, you really can’t beat the feel of the low end being supported by a powerful 12 or 14-inch speaker cone (other sizes also available!).

Plus, you can rattle the windows if you want to! Which is fun (unless you’re living next door).

Without a great low-end, all those fancy highfalutin speakers - with their swanky mid and high-range frequencies - just wouldn’t sound as good.

So, let’s save some love for the subwoofer.

But, to get the best from your subwoofer you need to make sure that you hook it up correctly.

It may seem like an easy speaker to install. But there are a few things that you should think about when wiring up your subwoofer.

So, what do we need to know when we consider how to connect a subwoofer?

Subwoofer Connection Types

There are two main ways of connecting a subwoofer to your speaker system:

  1. Low-level connection: also known as an LFE, .1 or line-level connection
  2. High-level connection: also known as a speaker level connection

The one that you will use will usually depend on the type of amplifier that you are using to power your speakers. And sometimes on the type of audio that you are listening to.

Many subwoofers will have both connection types. However, some may have only one or the other.

Some subwoofers, like those made by the popular subwoofer brand REL Acoustics, have a separate low-level and LFE connection. However, most brands will just have a low-level and/or a high-level input.

It's a good idea to check this before you buy a new subwoofer. To make sure that it has the right input connections for your system.

Although, in most cases, you won't have a problem.

What Is a Low-Level Subwoofer Connection?

The low-level connection on the rear of a subwoofer will look something like this:

Low-level (line level) input connection on the rear of an SVS SB-2000 Pro subwooferSVS SB-2000 Pro Subwoofer Low-Level Connection
Image Credit: SVS

Note that SVS uses the term line level, rather than low-level. It's the same thing.

The most common use for a low-level subwoofer input is when you are using an AV receiver for multi-channel surround sound audio.

Most AV receivers will have a dedicated subwoofer pre-out on the back. This will usually be marked as ‘sub’ or LFE. 

The AV receiver will then send two types of low-frequency sound to your subwoofer:

  1. The LFE track on a surround sound movie. LFE stands for low-frequency effects. Multi-channel soundtracks that you play on your system are usually 5.1. Sometimes they maybe 7.1. The ‘.1’ refers to a special LFE track that contains low-frequency special effects. This means that when the soundtrack is mixed, there is a dedicated channel of audio reserved for all the low-end sound effects and rumbles – the LFE track. This channel is usually sent to a dedicated speaker in your system which is perfectly designed to play these low-end sounds – the subwoofer! However, if you don't use a subwoofer, then full-range speakers can reproduce the LFE track.
  2. AV receivers also use something called bass management. When you set up an AV receiver you can tell it to send low frequencies from any of the other surround speakers in your room to the subwoofer. Why? So that you help the performance of your surround speakers and send the low-end frequencies to a speaker that is specially designed for the low bass. Bass management does this by setting a crossover frequency for each surround speaker. Then, everything below this frequency will be filtered from the main speaker and into the subwoofer – via the low-level input. The crossover frequency can be different for each speaker – or the same. You don’t have to enable bass management in your AV receiver, but most people will.

However, you don’t have to restrict your listening to surround sound movies. Many people enjoy listening to music using their front two stereo speakers and a subwoofer.

This is called a 2.1 speaker system.

The same rules apply though. There is no LFE channel in music but the bass management in the AV receiver will send some of the low-end frequencies into the subwoofer.

From the kick drum and low bass guitar notes, for example.

Some people like the sound of stereo music using the large subwoofer driver to fill out the low-end. I do. 

Some don’t like it and prefer to hear the natural balance of sound provided by their stereo speakers alone.

An AV receiver isn’t the only reason to use the low-level subwoofer connection.

If you are using a stereo amplifier with left and right pre-out connections – or a dedicated sub out - then you can also use the low-level inputs on the subwoofer.

So, you would usually use the low-level connection on your subwoofer if:

  1. You are using an AV receiver with a subwoofer pre-out
  2. You are using a stereo amplifier with a subwoofer pre-out
  3. You are using a stereo amplifier with stereo pre-outs

Bottom line? If you are using an AV receiver and want to use the bass management in your receiver to get a better low-end than your surround sound speakers can provide – then use the low-level subwoofer connection.

What Is a High-Level Subwoofer Connection?

The high-level connection on the rear of a subwoofer will look something like this:

High-level connection on the rear of an SVS SB-1000 subwooferSVS SB-1000 Subwoofer High-Level Input Connection
Image Credit: SVS

It will often be speaker wire terminals - like the speaker connections on the back of an amplifier.

However, another common high-level connection type is a Neutrik Speakon connection. It looks like this:

Neutrik Speakon connection on the rear of a subwooferNeutrik Speakon Connection on the Rear of a Subwoofer

The main advantage of using a high-level subwoofer input connection is that the speakers and subwoofer receive the same audio signal.

There are no potential phase issues between the mid and low frequencies. And the sound signature of the amplifier will be present in both signals.

In most cases, you would use the high-level subwoofer connection when you want to connect a subwoofer to an amplifier that doesn’t have a dedicated subwoofer output or a stereo line-out.

This would usually be a stereo amplifier – although some older home theater receivers might not have dedicated subwoofer outputs. 

Some stereo receivers do have a subwoofer output – but most don’t.

So, if you are using a stereo amplifier and speakers for listening to music or movies – and you would like a 2.1 system with a subwoofer – you can use the high-level connection on the sub to filter the low frequencies from the same audio that is going to your stereo speakers.

There is another alternative. 

Even if you have an AV receiver with bass management and a sub output, you might want to use the low-level connection for movies – and a high-level connection for listening to music.

Some people prefer the sound of music using a high-level subwoofer connection for music as it may give a more natural sound. Rather than using the digital filtering in the receiver to send the low frequencies to the sub.

So, you would usually use the high-level connection on your subwoofer if:

  1. You are using a stereo amplifier without a dedicated subwoofer or stereo pre-outs.
  2. You are using an AV receiver or stereo amplifier with a subwoofer pre-out or stereo pre-outs - but prefer the sound of music via the high-level connection.

Of course, it doesn’t just have to be music that you listen to when you use the high-level inputs on an AV receiver.

You can watch movies too. It’s just that you won’t get any bass management or LFE channel from the high-level connection.

Unless you have a REL subwoofer. For movie audio, REL Acoustics recommend that you make a high-level connection and use their dedicated LFE low-level input.

As they say, there are many ways to skin a cat (not that I've tried – all you cat lovers out there). You can decide which one you prefer.

Connecting the Subwoofer

Now that you understand the different options, let’s look in more detail at how to connect a subwoofer.

These examples mostly use SVS subwoofers. These are high-quality speakers and they have a range of different models to suit any home theater room.

However, you may have a different brand. So, the connections and controls that you have maybe slightly different. 

But, generally, most subwoofers will have similar options and so you should be able to follow along without a problem.

If in doubt, always refer to the manual for your subwoofer. Go on. It won’t bite!

How to Connect the Low-Level Input on a Subwoofer

The low-level input on your subwoofer will usually require a single RCA cable to connect to your AV receiver.

Although you can buy dedicated 'subwoofer cables', you don’t have to buy one of these if you don’t want to.

Any RCA interconnect will work. Although, I wouldn't use the thin, cheap RCA cables that often come bundled with a DVD player. You can if like, though.

Mediabridge ULTRA Series Subwoofer Cable (15 Feet)
Click For Latest Price

A thicker coaxial cable with more shielding should offer better performance and more protection for noise and hum in the signal. But in most cases, you shouldn’t need anything too extravagant.

As with all cables, if you need a particularly long one – say 20-feet or more - then a more expensive brand with a higher build-quality might minimize signal interference.

But for shorter runs, any well-made cable will be fine.

You will connect this cable from the subwoofer pre-out on your AV receiver to the LFE or mono line-level input on your sub.

All subwoofers will have a low-level input of some description.

The example here is the very popular SVS SB-2000 Pro:

SVS SB-2000 Pro SubwooferSVS SB-2000 Pro Subwoofer
Image Credit: SVS
CLICK FOR LATEST PRICE

In the picture below you can see an example of the low-level inputs:

Connecting an AV receiver subwoofer output to an SVS SB-2000 Pro subwoofer inputAV Receiver Subwoofer Output to SVS SB-2000 Pro LFE Input

Different brands will label this in different ways. 

However, if there are two RCA line inputs then one will be usually be labeled LFE or mono. This is the one to use for a single subwoofer output on an AV receiver.

Why Does My Subwoofer Have Two Line Level Inputs?

It is common for some subwoofers to have two line-level inputs.

You can use these if you have a stereo receiver or preamplifier with stereo pre-outs.

SVS SB-1000 Subwoofer Dual Low-Level Input ConnectionsSVS SB-1000 Subwoofer Dual Low-Level Input Connections
Image Credit: SVS

Connect two RCA interconnects from the stereo pre-out of the amplifier or preamplifier – to the left and right inputs on the subwoofer.

Connecting a stereo amplifier to a subwoofer with dual line-level inputsConnecting a Stereo Amplifier to a Low-Level Subwoofer Input

In this case, you won’t have any bass management from the amplifier and so will get the full range audio signal.

Therefore, you would enable the onboard line-level filter on the subwoofer to balance the sound with your main speakers.

How to Connect the High-Level Input on a Subwoofer

Remember, when you use the subwoofer’s high-level input, you are receiving the full frequency range audio signal from your amplifier.

So, you need to feed the complete audio signal from the amplifier’s speaker connections into the speakers – and the subwoofer.

I have seen a couple of different ways of doing this. Always consult the manual of your subwoofer in case it is different from the methods I describe here.

Connecting a Subwoofer with Speaker Wire

A common high-level connection type is speaker wire connectors on the rear of the subwoofer.

An excellent subwoofer that has this type of connection is the SVS SB-1000:

SVS SB-1000 SubwooferSVS SB-1000 Subwoofer
Image Credit: SVS
CLICK FOR LATEST PRICE

You can see the high-level inputs on the rear of the SB-1000 here:

SVS SB-1000 subwoofer rear high-level input connectionsSVS SB-1000 Subwoofer High-level Input Connections
Image Credit: SVS

If we take close look at the back, you can see the speaker wire connections. These are the same type of connections that you will find on many Hi-Fi speakers.

You would connect this by taking two pairs of speaker wire from the rear of your amplifier.

Connecting a Stereo Amplifier to a High-level Subwoofer InputConnecting a Stereo Amplifier to a High-level Subwoofer Input

One pair will connect to your speakers in the usual way. The other pair will connect to the back of the subwoofer.

If you want to know more about this, take a look at how to connect speaker wire.

Once you have this connected, you will use the filter in the subwoofer to blend the sound with your front stereo speakers.

Connecting a Subwoofer with a Neutrik Speakon Connection

Another common high-level connection type for subwoofers is a Neutrik Speakon connector.

You can see an example of the connection and cable here:

Neutrik Speakon Connection and CableNeutrik Speakon Connection and Cable

The Neutrik Speakon cable has a connector at one end which plugs into the port on the rear of the subwoofer.

The other end has three bare wires that connect to the speaker terminals on your amplifier. This might be an AV receiver, stereo amplifier or preamplifier.

The common way of wiring this is that one wire goes to the positive terminal of the right channel.

Another to the positive terminal of the left channel. And the final wire connects to the negative terminal of either channel – but not both.

Connecting a Stereo Amplifier to a High-level Neutrik Speakon Subwoofer InputConnecting a Stereo Amplifier to a High-level Neutrik Speakon Subwoofer Input

The purpose of this is to preserve the earthing of the amplifier and to avoid introducing ground loop hum.

The wires are color-coded and you must connect the wires to the correct terminals. Consult your subwoofer manual to make sure you get this right.

After you have this in place, the process is much the same as the previous example. 

You would use the subwoofer’s filter to balance the low-end frequencies with that of your front full-range speakers.

Can I Connect Both the High and Low-Level Connections at the Same Time?

Maybe. But you should check the manual of your subwoofer to see if this might be a problem.

Some models allow this. Some recommend that you choose between one or the other.

Of course, this will only apply to a subwoofer that has both high and low-level inputs.

However, even though you can have them both connected, it’s not usually recommended to have audio going through each connection at the same time.

Why? 

Firstly, because the conflicting low-end frequencies will likely muddy the sound and make it difficult to control the bass.

And secondly, you might be in danger of overloading the amplifier and subwoofer with audio levels that it simply isn’t designed for.

So, why would you want to connect both?

Because you might want to listen to some material using the low-level connection and some using the high-level input.

A common example is with an AV receiver.

Movie audio, with its loud explosions and low-end effects, is usually best heard using the low-level connection. The LFE channel and low frequencies from your surround speakers are all routed to the subwoofer.

However, if you want to listen to music on the same system, then using the high-level input might give a better balance to the sound.

How do you configure this to work? Well, I shan't lie, it can be complicated!

If you want to listen to music on an AV receiver using the high-level connections, you need to disable the bass management. So that a full audio signal is sent to the front left and right stereo channels.

Then, the low-level input won’t get any low-end audio sent to it.

To do this you can either set the front speakers to 'large' or select a pure direct listening mode. Pure direct disables all processing including bass management.

These options will vary between receivers. 

However, if you disable all processing, then any room EQ will also be disabled on the receiver. This may make the low-end muddy if the receiver’s EQ is doing a lot of work on the bass frequencies. 

But all this depends on your room, your speakers and the location of the subwoofer.

Of course, you don’t have to use the high-level input to listen to music. The alternative is to use the low-level input for everything – including music.

A standard stereo listening mode on your AV receiver will still use bass management to filter the low-end from your main speakers and pass it to the subwoofer.

It will also use any EQ that room correction has enabled. This will often give a cleaner bottom end to the sound. 

I prefer this option, but you might not. It will depend on your room, amplifier and speakers - and just what sounds best to you. 

There isn’t a right or wrong. Simply different.

Don't let anyone tell you that one sounds right and the other not.

Apart from if it’s me. I'm always right. :-)

How to Connect a Wireless Subwoofer

There may be times when connecting your subwoofer with a cable is plain old frustrating.

It’s easy enough if your subwoofer is located close to your amplifier.

But one of the advantages of a sub is that the low frequencies can be difficult to localize. Which means that you have the freedom to place the subwoofer pretty much anywhere in the room.

The downside of this is that you might need some very long cables to get to your favored position. 

Long cables can introduce noise in an audio signal – and they can be difficult to hide if you want to keep your room looking clean and tidy.

Fortunately, there are several solutions these days for making a wireless connection to your subwoofer.

The SVS SoundPath Wireless Audio Adapter is one simple solution to this problem.

SVS SoundPath Wireless Audio AdapterSVS SoundPath Wireless Audio Adapter
Image Credit: SVS
CLICK FOR LATEST PRICE

It comes with transmitter and receiver modules.

All you need is to connect the subwoofer output of your receiver to the audio input of the transmitter.

Then, connect the audio output of the receiver into the line input of the subwoofer.

Once the modules are paired it will send full range 5Hz – 24 kHz audio from the receiver to the sub.

The modules are supplied with USB power supplies which need to be connected to a power source. Or the newer SVS subwoofers also have a USB connection on the rear for powering the modules.

The timing and bass management is performed by the AV receiver.

While designed to be used with SVS subwoofers, these modules can also be used with any subwoofer with a low-level line input. Or, any powered speaker or amplifier. 

How to Connect Two Subwoofers to an AV Receiver

While a single subwoofer is fine for most rooms, there can be several advantages of installing two - or more - subwoofers.

The main benefit of multiple subwoofers is to even out the bass response around your room. So that every listening position will receive a balanced sound of low, mid and high frequencies.

The problem with low bass frequencies is that the wavelength of the sound waves is pretty long. And this can cause all sorts of problems when trying to get a balanced sound in a small room. 

Adding another subwoofer can help to spread the bass in the room and avoid any areas with peaks or troughs in certain frequencies.

So how do you add a second subwoofer to your system? There are a few ways.

1. AV Receiver with Dual Subwoofer Outputs

Many modern AV receivers now come with two subwoofer outputs. 

Therefore, the easiest way of adding another subwoofer is if your AV receiver has this option.

All you need to do is connect the ‘Sub 1’ pre-out to one subwoofer. And the ‘Sub 2’ pre-out to the other.

Two subwoofer pre-outs on the rear of an AV receiverTwo Subwoofer Outputs on the Rear of an AV Receiver

You would connect each with a single RCA cable as explained previously.

Most AV receivers will simply send the same audio signal from each output. 

However, some higher-end receivers have an independent audio feed from each output. This can make it easier to EQ and balance the bass in the room as subs in different positions might need different treatments.

2. Use a Y Splitter Cable

If your AV receiver only has a single subwoofer out – don’t despair.

A simple solution is to buy a Y-lead RCA cable.

This type of cable has a single RCA connector at one end – but which splits into two separate RCA connections at the other.

AmazonBasics 1-Male to 2-Male RCA Audio Stereo Subwoofer Cable
Click For Latest Price

You just need to connect the single connector to the subwoofer pre-out of your AV receiver. And plug the two extensions into each subwoofer input.

Then just set up your AV receiver as normal.

The main thing to consider is how far away – and how far apart – the subs are. The cable will need to reach both and so it’s easier if they are relatively close together.

If this might be a problem, an alternative is to buy a shorter Y-adapter like this one:

Mediabridge Ultra Series 12 Inch RCA Y-Adapter
Click For Latest Price

Then you can just connect two longer, separate RCA cables to each sub.

This might make it easier to run cables to wherever the subwoofers are in the room.

3. Daisy-chain the Subwoofers

You can only do this if supported by your subwoofers. But some subs have two line-level connections – an input and an output.

In this case, you would connect the AV receiver to the first subwoofer as normal.

Then you would connect an RCA cable from the output of the first sub into the input of the second sub. Like so:

Daisy chain connection of two subwoofersWiring Two Subwoofers with A Daisy Chain Connection

This is called daisy-chaining. Where the signal passes through one device and on to another.

This allows you to simplify the cabling in your room and add an extra subwoofer to a single AV receiver output.

You can also use this method to add even more subs around your room.

Always check the manual of your subwoofer to understand any limitations to this process.

For example, you should only daisy chain the same type of connection. This means you should only use the stereo line output on subwoofer 1, if the AV receiver is wired to the stereo line level input.

Conclusion

So, there you have it. And you thought connecting a subwoofer to your speaker system was easy!

Well, the good news is that it can be. 

But there are several things to consider when hooking up a subwoofer.

The main thing is to decide if you want to use the high-level or low-level connections. And if your hardware will support both these options.

While connecting the cables is fairly straightforward, it can get complicated when working out how to configure it all.

However, once you have it all worked out, then adding a high-quality subwoofer to your speaker system can make all the difference in getting a fantastic sound in your room.

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How to connect a subwoofer

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About Home Cinema Guide

Paul started the Home Cinema Guide to help less-experienced users get the most out of today's audio-visual technology. He has worked as a sound, lighting and audio-visual engineer for around 20 years. At home, he has spent more time than is probably healthy installing, configuring, testing, de-rigging, fixing, tweaking, re-installing again (and sometimes using) various pieces of hi-fi and home cinema equipment.