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Test CD : In Phase / Out of Phase test

I am looking for some help with the following problem?

Many test disks will play in phase and out of phase signals to assist in loudspeaker set up

In phase – my system plays back a signal that is tightly in focus and directly centered between the two loudspeakers. Good.

But, for out of phase – where playback should have no apparent source and seem like it is coming to you from everywhere in the room, my system whilst reproducing a signal that is diffuse and not centered between the two speakers – sounds stronger from the right speaker than the left, like the right speaker is the source.

I have tried the following

1. Changing the toe in of the right speaker so it does not point as directly at the listening position. The problem still remains

2. Swopping the left and right speaker – the problem still remains

3. Passing a 1KHz test tone and pink noise through the system and measuring SPL (dB) 1m from each speaker. The measurements were identical. Taking the same measurements from the listening chair however showed a 2dB stronger signal at the right side?

Any suggestions?
kiwi_1282001

Showing 2 responses by zd542

zd542
5,339 posts
 
Nothing is wrong with your system. There are different ways you can be out of phase. In the demo that you are talking about it sounds like the speakers are out of phase with each other. This is not something that you would normally need to worry about. You will never see music like this.

Try this: Turn your amp off and go to one of your speakers (doesn't matter which one). Reverse the speaker cables; if your speakers are biwired, switch both. Just to clarify, put the + (red) on the - (black) and the cable that is hooked up to the - (black) to the - (red). Play the recording that sounded messed up and it should sound normal. Remember, just reverse the cables for 1 speaker, not both.
zd542
5,339 posts
 
I was in a hurry when I typed out my response this morning. Also, with the posting delay, things can get confusing. The last post I see is Kiwi from today, the 3 paragraph states he will try my recommendation (zd542). Just to keep context, this response in response to everything up to the post I just mentioned.

Something I need to clarify. When you say test discs, I'm taking that literally. These are actual recordings that are to be used in the set up and evaluation of audio equipment. That's what I'm going on. If the recordings you are referring to are just a bunch of well recorded, audiophile pressings of music that are great for really testing a system, then my first post probably doesn't apply.

The reason I said that there is nothing wrong with your system is that the phase test that you describe, should sound messed up. Its typically used to show what a system will sound like if you made an error connecting your speaker cables. If that's the case, there really is nothing to fix. I had a look at the 2 systems you have listed. It looks like you really know what you are doing and take audio very seriously. Given that, I just don't see you messing up connecting speaker cables. That's why I say there is nothing wrong with your setup.
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