Do I Need A “Y” Splitter To Hook Up My Subwoofer?

Norvan Martin
As an Amazon Associate, we earn from qualifying purchases made on our website.

When connecting your active subwoofer to your AV receiver, it is common to use subwoofer cables or basic RCA cables.

However, you may also find people using Y adapter cables. But what is a Y adapter cable and why use one?

Does it offer better bass?

There are many types of subwoofer cables, so when hooking up your subwoofer to your receiver, you do not need to use a Y splitter cable, any standard single RCA or subwoofer cable will work just fine.

However, there are a few benefits to using a Y cable including increased dB levels,  better frequency separation, better bass response on some subs, etc.

Additionally, if your subwoofer is humming with the RCA/sub cable plugged into it, then you should try using a “shielded” subwoofer cable.

In general, using a subwoofer cable helps to ensure optimal performance.

What Is a Y Adapter Cable?

A Y adapter cable or splitter cable is a cable that can be used to connect your subwoofer to your receiver.

As its name suggests, a Y cable has three ends, just like the letter Y. It has one common end and two other ends. What Is a Y Adapter Cable and what is it used for

We use Y adapter cables to connect a stereo amplifier or receiver to a mono-input subwoofer. We also use them to connect stereo subwoofers to receivers or amplifiers. 

As you can see, there is a single connector on one end which then splits into two.

The split occurs either as a zip cable or with a small box that hides the split which then finishes with two connectors at the other end.

What Is A Y Cable Used For?

As we have mentioned before, a Y cable is used to connect your AV receiver to your mono subwoofer and thereby transmit the low frequencies the subwoofer needs to operate.

What Is A Y Cable Used For

Now you may be wondering if you can use a Y cable to combine two signals. This is not recommended because you will not have control over the way the signal is combined.

Advantages of Using a Y Splitter

Should You Use A Subwoofer Y Cable?

First of all, you can hook up a powered subwoofer properly with regular RCA cables. A “Y” splitter cable is not necessarily needed.

However, when choosing whether to use a subwoofer Y splitter cable or not will depend on the design of the sub and the amp in the subwoofer.

y cable subwoofer connection increased db

The fact is, in most cases, it will make very little if any, discernible difference unless you are using a stereo signal.

On the other hand, if you drive your sub hard, then you may well find it will make a noticeable difference!

Here are some other reasons to use a subwoofer Y slipper cable:

1. Increase dB Levels

In general, most receivers come equipped with a single sub output while most powered subwoofers come equipped with left & right inputs.

Since both inputs are driven, you will get more input signal when the amp sums the two inputs together. Increase Subwoofer dB Levels

In other words, you will be increasing the decibel level because the Y cord will allow you to sum two coherent inputs (or voltages) from both inputs (L and R) on the back of the sub.

However, if you choose to do this, please note that connecting both inputs in parallel will double the input voltage which equals a 6dB boost in output.

In other words, by using a subwoofer Y cable for both the left and right subwoofer input, you can increase the bass output of your subwoofer by about 3dB.

Many people like this potential to boost the sub’s output signal. In general, you will increase the sound level from 3dB to 6 dB.

You will be able to do this on most, but not all subwoofers. 

If you want to achieve the same thing without a Y cable, you will need to use 2 RCA–RCA cables.

You would then wire the RCA cables from the preamp outs to both sub inputs. This will then cause the stereo summing to occur within the subwoofer.

Why would you want to do this?

Well because it will give you stranger mono bass while at the same time preserving the stereo signal separation going into the main amplifier within the sub.

2. Better Bass

This one is arguable because you won’t have better performance with all subwoofers.

However, the fact is that many (again not all) subwoofers will have increased clarity and bass response when both inputs are fed with a mono signal.

3. Prevent Bass Chipping Out At Low Levels

Some subwoofers have an auto-on feature which can sometimes cause the bass to cut out when the sub is operating at lower levels.

The main reason for having auto-on is to decrease power consumption and internal heating.

Moreover, sometimes the power coming from the receiver or preamp isn’t set high enough for the sub’s amp to sense that it needs to turn on. Auto-on is used to prevent this problem as well.

Many people use a Y splitter to connect both subwoofer inputs so they can prevent this problem because the auto-on mode of some older subwoofers (e.g the Velodyne CH-12) may not come on at lower levels without the use of a Y cable.

How To Connect Your Receiver and Subwoofer Using A Y Splitter 

4. Hum Reduction

Subwoofer hum is a common problem in home theater systems. It is so common that sometimes your subwoofer may hum without any input.

Using Y splitter cables can reduce the amount of Radio Frequency (RF) and Electromagnetic (EM) interference that is fed to your sub which of course causes that annoying hum.

This is because when you use a Y splitter, you don’t leave the second subwoofer input open.

Most Y splitter cables are built with effective copper-braid shielding that eliminates any occurrence of signal interference and will offer noise-reduced transmission and overall better quality.

However, a great way to reduce subwoofer hum caused by RF on the line is to use a “shielded” subwoofer cable.

5. RCA Adapter May Gather Dirt

If you use an RCA adapter and leave one of the RCA inputs open, then dirt may get clogged in time.

6. Some Subwoofers May Need A Y Splitter Cable

The fact is that some older subwoofers may actually need a Y cable. This is because the left channel L may not default to the mono signal.

Disadvantages of Using a Y Splitter

The fact is that any single, standard RCA or subwoofer cable should do just fine for your subwoofer.

A Y splitter is definitely not a must for most subs.  Any cable designed for subwoofer use should be just fine.

Here are some reasons why you may not want to use a subwoofer Y splitter:

1. Receiver With One Mono Sub Out

If you are using an AV receiver with bass management, it may only have one (mono) sub-out connector.

In this case, you can just run one RCA to RCA cable. You can achieve pretty good performance with this setup once you set everything to their relative 0 positions, especially sensitivity.

2. RCA Cables Are Easy To Find

It is rather easy to find a RCA cable at your local home department store or just lying around your house.

However, Y splitter cables aren’t so common, so you may need to check a specialized audio equipment store to find one.

How Does Y-Adapter Cable Work?

A Y-adapter cable works simply by dividing one audio signal into two similar or identical audio signals, thereby enabling the input of the audio signals into two different output devices.

How To Connect Your Receiver and Subwoofer Using A Y Splitter 

The Y splitter is quite easy to connect. One end of the cable will be plugged into the Subwoofer Output on the back of your receiver.

This output jack is sometimes labeled as SUB, SUB OUT, or SUB PREOUT. It is common to connect your subwoofer to your receiver with subwoofer pre outs.

All you need to do is to connect the single end from your subwoofer out on your receiver.

Next, you need to connect both L and R inputs on your sub using each end of the Y splitter.

Other Ways To Connect Your Subwoofer

There are many ways to connect a subwoofer to a receiver. This includes using RCA cables, subwoofer cables, and even wireless.

You can even use a basic speaker wire to connect your subwoofer to a receiver once it has a jack.


The bottom line is, that subwoofer Y splitter cables are not necessary. You can use them to gain the benefits mentioned above, but they are not required.

You can use RCA cables or subwoofer cables when hooking up your sub and either will work just fine.

In terms of Y splitter cables offering better bass quality, this may or may not work for your subwoofer.

However, Y cables only cost a few dollars anyway, so there is no significant risk involved.

Most importantly if you decide to get a Y splitter, make sure you use a good quality Y adapter that is shielded so that you avoid the cable picking up unwanted noise and causing subwoofer hum.

Share This Article
Norvan Martin is the founder of He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin