How to Phase Your Speakers





Introduction: How to Phase Your Speakers

About: I am an AV and IT guy... I have been involved with sound and lighting since I was 7 yrs old. I currently do Information Technology work for a living, and professional sound as a side job. Although I do bot...

In this instructable I will cover phasing of speakers.  This is designed to be just a introduction to phasing, some phasing techniques are very advanced, however, I will show you what I think is the easiest way to think about phasing.

Step 1: What Is Phasing?

Many people might ask: "What is phasing?".  That can be very difficult to explain, but I will do my best.  When you produce artificial sound from multiple sources, you always run the risk of being out of phase.  What I mean by out of phase is this: one source is "contradicting" what the other source is doing.  When a speaker produces sound, it is vibrating back and forth.  When you phase a speaker, the idea is to have both speakers moving in the same direction.

Step 2: When Do You Need to Phase?

Let's determine if you even need to phase your speakers.  There are a three questions you need to ask yourself.

1.  What were these speakers meant to do?  (Pro Audio, Stereo system, Surround Sound, etc.)
2.  What was the amplifier meant to do?  (Pro Audio, Stereo system, Surround Sound, Powered Speakers, etc.)
3.  What orientation was the system designed to be used in?  (Facing each other, same direction, surround, etc.)

If you are using the system in the way it was designed, then you do not need to phase the speakers.  But if you have a system that was designed to be used with the speakers facing each other and they are now facing the same direction, or you have a system that was designed to be used with the speakers facing the same direction and they are now facing each other, you need to phase them.

Step 3: How to Reverse the Phase

Now that you have determined if you need to phase, the next part is easy.  This is how we phase a speaker.  Normally on a straight phase, the marked wire would always be in the positive jack of both the speaker and the amp.  With a reversed phase, the marked wire should be reversed on either the amp or the speaker.  (Not both.)   In this way you are reversing the polarity so that when the speaker would normally move out, it moves in; and when the speaker would normally move in, it would move out.

Step 4: Copyright

Please note that I do claim copyright to the information. I did not use any specific sources when compiling this information, all of this is from my personal experience.

You may quote parts of this information for educational purposes. Under no circumstances will you sell this information.

I do not own the copyright to any of the images, however, as far as I have been able to find, I have the right to use them in this instructable. If there is any question about whether or not I have the right to use these images, please contact me. I have no intention of stealing anyone's intellectual property.

Use of this information implies that you agree to these copyright terms.

© 2011



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Phasing can also be used to simulate surround sound (pretty well, I might add). Your receiver needs to have two pair of speaker outputs. Hook up your front speakers properly phased (i.e., receiver+ to speaker+ and receiver- to speaker-). Get a pair of cheap rear speakers (matched properly ohm-wise to your front speakers so volume output matches). Hook up the rear speakers to the second speaker terminals on your receiver. However, hook up these rear speakers as follows: receiver+ to speaker+ but speaker- to speaker-. In other words the left and right rear speakers have their + going to the L and R receiver+ but their - going to each other. This will only produce sound from the rear speakers that is common to both left and right channels. It gives a very nice and subtle spatial effect to your music. Depending on the front and rear speakers, it might take a cheap volume control for the rear speakers so that their volume is more background than foreground. Some receivers might have a fader control that will accomplish this also. IMHO, the sound is more pleasing than some of the spatial effects that are built-in to many receivers out there today.

1 reply

Nice! I never thought about doing it that way, but you're right, it would sound pretty decent. Thanks for sharing!

Anything is possible, if you don't care who gets the credit.
— Harry Truman

It appears that the figure in step 2 shows a single source ( for example the left channel) connecting 2 speakers in series (upper image) or parallel (lower image). Shouldn't it show 2 sources?

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Not necessarily. Basically that figure is showing a Mono setup, which is what you would use in most professional audio setups. Stereo (two audio channels) is what you would use in a home theater setting, or in professional audio if you need to pan a track or channel to a specific side of a room for some reason. (For instance: making thunder sound like it's moving from one side of the room to another.)

You can't copyright common knowledge. You didn't invent the process of phasing. Sound engineers have been doing this for decades. I phased my speakers back in the 70's when I was 13.

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I'm not copyrighting the process of phasing, merely the way that I presented it. If you want to create an adaptation of how I presented it, fine. If you want to create your own presentation on how to phase your speakers, fine. But if you copy me word for word, then we have a problem. That is all that I claim copyright to.

Well this is special, you should share some useful information because I have found out more from googleing your instructible subjects than what you have provided. Did you know sound isn't really just a sin wave. A pure note will appear as a sin, but it will actually zig-zag, even a tuning fork will, which is what this image is of

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Yes... I did know that... But almost all sound can be created from or reduced to a sine wave at some point. (And it is sine wave... Not sin wave... The wave didn't do anything bad!)

I really don't understand why that would affect phasing though. The concept is still the same, and it is still necessarry. If there is something you think I missed, please let me know... I am more than happy to add it. The purpose of my instructables is to provide the basic information that professionals like myself use day to day in a way that someone who knows nothing about sound can understand.

How is this spam?

It's not. That poster created multiple SPAM topics, and seems to be bored enough to go cross-post around the site.

I noticed his spam topics... there was also another poster who was saying my ibles were spam earlier yesterday... probably the same person.

Thanks to whoever deleted his post! :)

Definitely the same person. Some "gold farmer" in an Internet cafe in Shanghai, most likely.

Probably. If it's the same person, he posted three ibles trying to sell electronic hacking devices. Good ideas, but didn't show how to make them. (And one of them I'm pretty sure he ripped off a design that's already on the site!)

Copyright to what? How to connect your speaker the way you are supposed to? There's a + and - on the speaker and a + and - on the speaker output... Doesn't seem that hard to me...

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Forgive me for asking, but did you actually read what I published?  I didn't publish how to connect your speakers, I published how to phase your speakers.  There is a difference.  Connecting your speakers is involved in phasing your speakers, and by phasing your speakers you will connect them.  However, it is not as simple as connecting + to + and - to -.  I claim copyright to the information I provided in this instructable.  If you don't agree with what I wrote, then you wouldn't want to steal it, so you don't have to worry.  However, anyone who knows even the basics of sound will tell you that phasing is necessary if you want good sound.

I am not required to provide this information to anyone, but I don't see anyone else posting about how to phase on this site, so I figured I would.  I make up to $200 an hour doing professional audio and home theater design. Phasing is just one of the basics of my craft.  When you can "shape" sound, and make $200 an hour doing it, then if you still disagree with what I say in this instructable, then we can talk.

Every time I publish an instructable, people ask me why I put the copyright step in.  However, they ask me because I choose what my license agreement is when I publish the instructable, not because they think it shouldn't be copyrighted.  The reason I use redundancy, is that I never noticed the license link on the side of the page before I published an instructable, and I want to absolutely clear on what my terms are.

If you did read my whole instructable, and you didn't understand it, I will be happy to explain to you in more detail.  However, I sincerely doubt that you read the whole thing.


Isn't this just wiring the speakers in mono sound?

1 reply

In the diagram, yes. But you still need to do it with stereo as well. Same process, just swap the + and -.

When you spoke about the speakers facing each other or facing the same direction, should there be a difference with phasing them? I know that if you have two speakers facing the same direction, they should move in sync with each other, but if the speakers were facing each other, would that still hold true?

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No, think about it this way: when they are facing the same direction and are moving in sync (phased the same way), when both diaphrams push out, it pushes the sound in the direction that the speakers are pointing. When they are facing each other and phased the same, they are still pushing the sound in the direction they are facing, so the sound from one speaker is doing the oppisite of the sound from the other speaker since they are facing each other. Remember that a speaker produces sound by moving the diaphram in and out very rapidly. I like to take a snapshot in my mind of the diaphrams with a positive charge and visualize if the sound is moving in the same direction. I also have the ability to visulize how sound waves will interact with each other... but that's just something that I learned from experimenting, I never had someone teach me how to do that.