Why Do Subwoofers Have Left and Right Inputs?

Subwoofers are a fundamental part of your home stereo or car audio system. You usually connect only one subwoofer.

So, if you only need to connect one subwoofer, why are there two channels for left and right inputs?

Subwoofers have left and right inputs because a lot of media is mixed in the left and right channels. In theory, a subwoofer will only play the sound on one side if only one channel side is connected. That said, many subwoofers will let you connect only one cable and will still work as intended.

If a subwoofer is one speaker with two channels, it’s only logical to use a Y splitter, right?

Read on to learn the answer to this question and some other questions you may have.

Why Some Subwoofers Have Both a Left and a Right Input

If you ever listened to music or watched something on headphones, you must have noticed the stereo effect.

More often than not, the stereo sound has a spatial effect and makes the whole movie-watching experience more immersive.

You can achieve a similar effect with speakers.

So, what does this have to do with subwoofers having both left and right inputs?

The dual inputs make sense if you’re using two subwoofers, as you can make sound come from only one direction. However, your amplifier has to support this kind of output.

Why Some Subwoofers Have Both a Left and a Right Input

If you want to have stereo subwoofers, get the Soundavo PSB-200 Amplifier from Amazon.com. It has a built-in crossover that can power one or two subwoofers for a surround sound system.

However, if you’re like most people, you’ll only use one subwoofer.

In most cases, the dual inputs are there for redundancy.

After all, there’s always a chance you’ll use two subwoofers in the future, and ensuring you have both inputs means you won’t have to invest in a new subwoofer.

Pretty much every subwoofer in existence will work just fine with only one of the two channels connected. Sometimes the subwoofer will even label it as LFE.

Keep in mind that you will probably have to configure your amp if you’re using the left and right input.

Make sure to set the frequency response range somewhere between 20 and 300 Hz.

When you use the line left and right inputs, your subwoofer’s crossover will take over. You can use this to your advantage if you don’t want to use the amp’s crossover.

If you’re using low-frequency effects (LFE), your amplifier will usually configure it for you automatically.

Can I Use Only One Channel for a Subwoofer?

Most subwoofers allow you to only use one channel. The left and right channels on the subwoofer are for surround sound systems.

However, if you connect only one cable, the subwoofer will recognize it as an LFE input.

If your subwoofer doesn’t work when you plug the RCA cable into one channel, try plugging it into the other one.

Most subwoofers will use either the left or the right input as a universal LFE input.

If it still isn’t working, you can use a Y splitter. RCA Y splitters connect to both inputs on your subwoofer and the subwoofer output on your amp.

There is, however, one disadvantage to using only one channel for your subwoofer, which is that the volume will be slightly lower.

However, the sound stays the same, and if your subwoofer is already loud enough, it doesn’t matter.

You can even use this trick to stop the bass from overwhelming the whole song.

Do I Need a Y Splitter for My Subwoofer?

Y splitter for your subwoofer

In most cases, you don’t need a Y splitter for your subwoofer if it has both a left and right channel. You can connect one or two separate RCA cables to the subwoofer.

While your subwoofer will work without a Y splitter, there’s still a benefit to using one.

The sound quality will stay exactly the same, but it’ll be about 3 dB louder.

That’s a decent increase in volume, but do you really need it? After all, it can make your subwoofer sound too loud compared to other speakers.

If that’s what you’re after, I recommend getting the Amazon Basics Y Splitter from Amazon.com.

It is designed to work with lower frequencies for your subwoofer, and the cables are color-coded for a quick hookup.

Here is how to add a subwoofer to your amp using a Y splitter:

  • Get the right cable. Pay close attention to the length of the Y splitter because that’s the only cable you’ll be using.
  • Connect the 1-male RCA to the subwoofer port on your amp. It will be labeled as Subwoofer or LFE on most amps.
  • Connect the 2-male RCA cables to the left and right channels. The left is usually white, and the right is red both on the cable and amp.

You may need to adjust the crossover frequency and lower the gain a little bit. Other than that, your subwoofer should now work effectively.

Should I Use LFE or Left + Right on My Subwoofer?

Ideally, you should use LFE instead of left and right channels on your subwoofer and amplifier.

This is because it is easier to connect LFE with only one cable, and your amplifier’s crossover is better than the one in your subwoofer.

Should I Use LFE or Left + Right on My Subwoofer

LFE stands for low-frequency effects. Most songs, movies, games, and other media are engineered with an LFE channel in mind.

When you connect your subwoofer through LFE, it’ll take the intended frequency range.

So, there won’t be any clipping caused by an improperly configured subwoofer.

When the bass gets clipped, it has a mechanical clicking or buzzing sound, and it will make you think that your subwoofer or amp is broken.

Clipping can become especially distracting during intense movie scenes.

Explosions, car engine sounds, trains, choppers, guns, and other things sound bad when they clip. So, prevent clipping by using LFE whenever you can.

Since you only need one cable instead of two, doing so is also more convenient.

You can use any RCA to RCA male cable for LFE. This means if you have some leftover RCA cables from your speakers, you can use them instead of investing in new equipment.

Can I Connect a Subwoofer to the Speaker Output on an Amplifier?

Can I Connect a Subwoofer to the Speaker Output on an Amplifier

You can connect a subwoofer to the speaker output on your amplifier if it doesn’t have a dedicated subwoofer port.

Older receivers and amplifiers don’t have an LFE port and you will have to use the left and right channels to connect the subwoofer.

The only thing you have to do before connecting your subwoofer is to check the wattage and impedance.

If your subwoofer’s impedance rating is too low or too high, it won’t work as intended.

Impedance is measured in ohms. For example, if your subwoofer is rated for 2 ohms, but your amp supports 6 ohms or more, the signal will be too weak.

The bass will be underwhelming and distorted.

Depending on your amp and subwoofer in question, you may need to use an RCA plug on one end and a speaker wire on another.

Connect a speaker wire to the amp the same way you did for all other speakers.

Next, use an RCA adapter to connect it to your subwoofer.

You can buy the Moborest RCA Adapter from Amazon.com. It’s very easy to install because the positive and negative terminals are labeled, and you don’t even need a soldering iron.

The sound you get by connecting your subwoofer this way is unique.

The bass is smoother, and your music sounds more balanced than with the LFE port.

Why Do Subwoofers Have Left and Right Outputs?

Active subwoofers have left and right outputs for passive speakers. These subwoofers have a built-in amplifier, and you won’t need a separate amplifier or crossover to power this type of audio system.

Active subwoofers are the perfect solution if you get a headache when someone mentions amplifiers.

Most active subwoofers have two left and two right channels that let you create a custom 2.1 sound system.

You plug the subwoofer into your audio source and power source, then you connect the speakers to the subwoofer.

It’s a fairly straightforward setup.

The Polk Audio PSW10 from Amazon.com has both speaker output and input ports.

It’s a perfect choice to extend your existing home theater, and the bass it reproduces is phenomenal.

Final Thoughts

Subwoofers come with various output and input ports that let you connect the subwoofer to your car, home theater, computer, and so on.

Modern subwoofers and amplifiers have an LFE port that you should use instead.

It’s easier to connect, and you usually get better sound from LFE.

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