Subwoofer Phase Normal Or Reverse: The Ideal Phase for You

Subwoofers often sound better (or worse, who knows) when you turn the switch labeled ‘phase’ behind it.

It makes us wonder if all of the speakers in a room need to be in synced phases or not.

So the question for the day is which subwoofer phase normal or reverse?

The subwoofer phase should be normal during test runs. You can change it to reverse if you’re looking for a different outcome. Find out what’s working best for you. A subwoofer doesn’t need the reverse phase unless it’s wired out, out of phase, or inverted. If you prefer sounds to travel a long distance, then the reverse phase is just for you.

This is enough to help you clear your confusion. But hold on, you can also find out other reasons for a subwoofer phase affecting your experience.

Spare a minute and read along!

Now, if you just want a quick comparison between the two phases you can jump into our final verdict section.

Let’s dive in-

What is Subwoofer Phase?

The phase control of a subwoofer allows the speaker to delay incoming electrical signals by the conductors. You can tune the phase control from a range of 0 to 180. The 180 degrees phase setting reverses the subwoofer polarity. Delay can sometimes help the speaker integrate better with the other speakers in the room.s

But if the subwoofer is solo, the phase shift doesn’t make any audible difference. However, at high frequency, the sound effect is not as subtle. You can clearly hear the differences.

Here’s a graph explaining the audio frequencies of the normal and reverse phases of a subwoofer. The graph on top is the frequency of the subwoofer normal phase.

The one at the bottom is the frequency of the subwoofer reverse phase.

Here in the graphs, a speaker is tested with normal and reverse phases separately.

You can see that the difference between the frequencies of the normal and reverse phase is not much.

But at one point, the frequency in the normal phase decreases almost to zero.

And at that point, the frequency of the reverse phase is still high.

This means the wavelength of other speakers does not interrupt the wavelength of the subwoofer in the reverse phase.

But in the normal phase, the wavelength gets interrupted. This explains the noise cancellation effect.

Another fact, the polarity of the subs also changes if you switch the phases. That is mainly what causes the delay of the signal transmission.

So, when to use phase on subwoofer?

You should use subwoofer phase when you want to add electrical delay to your subwoofer. It’ll help your subwoofer to integrate with the other loudspeaker in the room.

Now, if you take a close look behind your subwoofer, you’ll notice a switch that is labeled ‘phase’ and control with degrees 0 and 180.

Let’s have a look at the quick difference between subwoofer phase normal and reverse.

Features	Subwoofer Phase Normal	Subwoofer Phase Reverse
Numeric Value	0	180
Speaker- Subwoofer Combination	If both present in the same room in the same direction	If both present in the opposite direction of the same room
Polarity	Not reversed	Reversed
Correct Use in Home Theater	When there’s only 1 subwoofer in the system	When there are 2 subwoofers, the 1st one is reversed

You can switch between these two phases using the controller. Usually, 0 degrees means a normal phase, and 180 degrees means the reverse phase of the subwoofer as we said earlier.

Some subwoofers have ‘variable’ phase control. These controls have more options along with 0 and 180 degrees.

That means you can set the subwoofer to any phase between 0 and 180 degrees. Just try it out and find your sweet spot for your best audio experience.

Should the Subwoofer Phase be Normal or Reverse?

You should prefer normal subwoofer phase for more clear sound experience, but at the cost of audio distortion. Normal phase subwoofers are also vulnerable to having noise. On the other hand, setting the subwoofer to reverse can provide louder sound. But be careful! It can also affect the longevity of your subwoofers!

Understanding the reverse or normal phase of a subwoofer is very simple. However, before we come to a conclusion, let’s learn about the phases of a subwoofer. 

And also, how it affects the sound quality-

In order to find out the best phase setting for subwoofers, we need to take a deeper dive-

Normal Phase (0 Degree)

When you buy a brand-new subwoofer, the phase will be usually set to normal. When the subs are in a normal phase, it’s called in-phase.

That means the incoming signal is synced with that of the other speakers around the room.

Now, you might want to know what happens when they sync-

The opposite movement causes a certain amount of noise reduction or cancellation.

Here’s a graph showing the frequency response of a subwoofer and the frequency of other speakers-

This graph depicts the frequencies of speakers in two different scenarios.

The first scenario [with the red line] is the frequency of all the speakers in a system with a normal phase.

The second scenario [with the blue line] is the frequency response of a single main speaker.

Now, does subwoofer phase make a difference?

Of course, it does. When the frequency is low, the difference between the response of speakers with normal phase and main speaker is maximum. This means the sound is clearer but has greater chances of distortion in the normal phase. But in the reverse phase, it’s the exact opposite. The sound is louder than ever.

Why Would You Prefer the Normal Phase?

If you’re playing the subwoofer in the normal phase, there’s no delay in transmitting incoming signals from the main channel.

This will make your listening experience smooth and uninterrupted. 

Which is great news, right? 

And as for noise cancellation, your home theatre experience will not be unsatisfactory. But your listening experience may not be complete.

You’ll find a lot of choices for you out there. So, here’s a list of speaker systems that will make your listening experience complete-

• VIZIO Premium Home Theater Sound System 
• Klipsch Black Reference Theater Pack 5.1 Surround Sound System

Why Won’t Normal Phase Work for You?

If your speakers are placed at non-uniform distances around the room, the normal phase will affect your listening experiences. 

You might hear sound dropping at certain points.

That’s because the other speakers (especially satellite speakers) generating the same wavelength interrupt the wavelength of subwoofers.

For this reason, you’ll hear distorted sounds from the speaker.

You can also add a subwoofer isolation system to make your listening experience better.

In this case, changing the placement of the speakers might decrease the noise cancellation effect.

However, switching the subwoofer phase setup to the reverse phase might save you the hassle.

Reverse Phase

If your subwoofer’s phase is set to 180 degrees, it’s in the reverse phase.

In this reverse subwoofer phase, the conductors, that transmit signals from the main channel, switch polarity. For this reason, the signal transmission gets delayed. 

As a result, the beat of the cone reverses and the sync becomes out of phase with the other speakers. The air beats through the back of the subwoofer driver as well.

Are you wondering what happens when the subwoofers are out of phase?

Subwoofers out of face is simply the reverse function of the normal subwoofer phase. The subwoofer cone will move in when the cone of the other speakers in your room move out. And vice versa. This function reduces a lot of the noise cancellation effects. Resulting in a clearer and louder sound production.

So you might be wondering, Phase subwoofer 0 or 180?

You should set the subwoofer phase to 0 when the subwoofer and the speaker are in the same room. This means that there is no delay. However, you should set the subwoofer phase at 180 when the subwoofer and speaker are facing opposite directions. This is known as the reverse phase.

Why Would You Prefer the Reverse Phase?

If you have a big room and you want your music to have the perfect bass, then the reverse phase is perfect for you.

If you’re planning for a setup, with rear backs or front heights, you can also consider using the reverse phase. 

Though reverse-phase also requires an evenly spaced-out sound system setup. Which is similar to the normal phase.

Make sure all the speakers have equal distances between them in a room. The speakers also need to be facing each other. Otherwise, there is a chance of distortion.

The wavelength of the subwoofers in a reverse phase complements that of the other speakers in a room.

This causes zero interruptions and decreases the noise cancellation effect. And because of this, the sound generated from the subwoofer is louder and clearer. 

This is why speakers in reverse phases integrate better with all other speakers in a setup.

However, you should always check which phase between 0 and 180 is suitable for you. In that case, you can use the Scosche SPL sound meter. You can find it on amazon. You should check which pink noise yields the best results to your ear using this. And thus, choose your phase accordingly.

Why Won’t Reverse Phase Work for You?

The reverse phase is not only about loud and clear music. Reverse phases can harm your speakers in several ways.

The delay in transmission often distorts a subwoofer, especially the big ones.

So, between 15 inch and 18 inch subwoofers, 18 inch subwoofers have greater chances of distortion.

There are some other ways the reverse phase can put your speakers in trouble.

Sometimes the dust in the port of the speaker can cause difficulties in the reverse piston movement. This is the reason why cleaning a speaker is important.

Not only does the speaker need cleaning, cleaning the cabinet is equally important.

It doesn’t matter if your speaker is covered by some of the ideal woods for speaker cabinets, make sure it doesn’t trap dust.

Also, there’s a possibility the port of your speaker is ill-designed. Thus, producing louder sounds when playing in the reverse phase.

The delay of the signal is often audible, especially in between a frequency range of 20hz-100hz.

Frequency	Sound
Below 20 Hz	Subtle
Between 20-100 Hz	Audible
Above 100 Hz	Subtle

Here’s a graph showing the frequency of subwoofers vs the frequency of other speakers-

Here in the graph above, the frequencies of speakers in two different scenarios are shown.

The first scenario [purple line] is the frequency of all the speakers in a system with a reverse phase.

The second scenario [blue line] is the frequency response of a single main speaker. 

The graph means that the sound quality of speakers in the reverse phase becomes loud and edgier. At low frequency, there was a huge difference in the response.

But the sound intensity of the speakers with reverse phases increased. This allows the sound to be loud and clear.

Now to find our perfect audio setting, we’ve got to test and trial both of the phases. 

After the subwoofer phase test, you can set the switch to a mid-level or upper-level bass. Which is somewhere beyond a frequency range of 100 Hz.

Keep in Mind –

• If you have more than one speaker, don’t switch phases one by one.
• Make sure both subwoofers in a surround system are in the same phase when playing.
• Cleaning the subwoofers once a month will save your surround system.

How to Set Subwoofer Phase?

To set your Subwoofer phase, you need to run musics that has a good amount of bass. Play the musics and listen how the bass works for a minute or two. Flip the subwoofer from 0-180 degree phase switch back and forth slowly and notice which settings yields the most bass.

The settings with the most bass is the right subwoofer settings for you!

Try out a few different recording to see if you find any difference. Turning the subwoofer volume hp will help a lot in this test.

However, if there is no notable difference in the two settings, keep the phase control in the 0 position.

Most of the time, different subwoofer settings won’t have any noticeable sound difference if you have only a single subwoofer. That’s where multiple subwoofer comes in play.

Start by setting the subwoofer phase to 0 for both speakers. All the subwoofers must have the same phase settings in case of multiple subwoofers. The volume of the two subwoofers should also be the same to evenly bear the low-frequency range energy.

How to set phase on car subwoofer?

Play some loud bass music through the receiver at one-quarter volume. Notch up the subwoofer amp gain until the subwoofer sound overpowers the speakers in the car without distortion.

Flick the phase switch of the car amp to 0 or 180 and try to figure out which settings sounds better.

Once you find that sweet spot you were looking for, keep it!

Note that it’s very important that subwoofers are in phase. If you find your subwoofers to be out of phase, you need to work on it!

Subwoofer Out of Phase: What does it Mean?

Subwoofers being out of phase means that the subwoofer and the main speaker are out of sync. An out of phase subwoofer will have its cone move in the opposite direction of the speaker’s woofer cones.

An out of phase subwoofer will produce terrible sounds with massive distortions and noise. More unsynchronized signals will create more interference.

This will degrade the output and longevity of both the devices.

How to Tell if a Subwoofer Is Out of Phase?

An out of phase subwoofer will produce a thin sound signal with little to no bass. Out of phase effects are stronger for low-frequency sounds. So it can face loss of bass. The bass will also move around the mix instead of coming from a single point.

If you’re not good enough at detecting low frequency sounds, you can take help from a friend.

Or, you can also use an SPL meter to notice how it affects the output of the subwoofer with pink noise.

How to Adjust Subwoofer Phase Alignment?

Well, we discussed how tremendously bad an out of phase subwoofer be for your listening experience. But we can’t leave just yet without a proper solution to the problem, can we?

So here’s how you can adjust your out of phase subwoofers:

Step 1: Match the Volume Levels of Both the Main Speaker And Subwoofers

Disconnect the furthest subwoofer from the main speaker. Try playing a test tone of the selected LPF setting in a mild volume.

From a position that is equidistant from both the subwoofer and the main speaker, adjust the level control. Set the level control settings where both the subwoofer and main speaker posses the same amplitude.

Step 2: Align the Phase of the Subwoofer and Main Speaker

Connect the positive speaker wire to the negative terminal. Do the same for the negative speaker wire. This will reverse the speaker polarity.

From a same seating position, slowly rotate the phase control in a clockwise manner . You will notice that the bass will gradually drop. After that, it’ll begin to rise again.

A null point will be created when the subwoofer and the main speaker plays the test tone out of phase, but at the same level. This will make the bass cancellation easier to notice.

Figure out where the bass appears to posses the least amplitude and set the subwoofer phase control at that position.

After that, reverse the speaker polarity one more time and that should align the subwoofer phase.

Final Verdict

Your decisions regarding the normal and reverse phase come down to some factors. These are- 

• the orientation of the speaker setup, 
• the room size, 
• the quantity of the speaker, 
• and lastly your personal experience.

Here’s a table that summarises the differences between the phases:

Now, ask yourself which car subwoofer phase 0 or 180?

The best way to choose a subwoofer phase between 0 or 180 would be to try out both of the phases. This way you’ll be able to find out which one works the best for you.

You can also check out why a subwoofer won’t work with a PC.

FAQs

What phase should a subwoofer be set to?

There’s no right answer here. If the normal phase doesn’t work for you, it can be changed to the reverse phase easily by flicking the switch. 

Do inverted subwoofers sound better?

In most cases, yes, the sounds of the reverse phase subwoofers are clearer and louder. And the bass is heavier than that of the normal phase. This occurs because the wavelengths produced by the reverse phase don’t interfere with the wavelengths of the other speakers.

How do I know if my subwoofer is out of phase?

For this, you’ll need to do a simple step. Observe the cone of the subwoofers, if the cone moves in when the cones of other speakers move out, it’s in the reverse phase. This is also known as the out of phase. 

Conclusion

Let us conclude by saying that your listening experience is totally up to you. Make sure to keep your subwoofers clean and dust-free for a better sound experience.

Do comment below and let us know which subwoofer phase normal or reverse, you are going for.

Until then, roll with the rhythm!