What could cause this strange stereo imaging problem?

[MakkaPakka]

I have a test tones CD which includes a stereo test. The voice goes left channel, left centre. centre, right centre, right channel. The voice comes from the corresponding position around the speakers so you know everything is in the right place.

What has happened is that left channel and left centre spoken word appear to come from the same place or even. at times, seemingly the wrong way round so left centre seems further left than left channel voice whereas everything is fine on the right. Also, when listening to music, the sound, after a while, sometimes shifts over to the left (this being the reason I reached for the stereo test in the first place).

I spent ages testing wiring, different speakers, headphones etc.

Ultimately I seem to have 'fixed' the issue by moving the speakers to the terminals for speakers 'B'. However, I'd like to understand what caused this problem in the first place. It seems odd that speaker terminals alone could behave in this way - the sound wasn't quieter but the stereo imaging was way off kilter. The amp is only a few years old so shouldn't really be failing.

Any suggestions from those with a technical grasp of such matters?

 

[matt49]

Bizarre. You say the sound wasn't quieter using the A terminals: was there any other difference at all as compared to the B terminals or was it only the imaging that was affected?

Matt

EDITED grammar

 

[Covenanter]

Logically if the speakers sound fine on one set of amplifier outputs then the source and speakers are ok and the problem is with the "A" outs on the amp.

Chris

 

[Crocodile]

Maybe you had them out of phase & corrected that when you changed terminals. Try going back to the A set & see it the problem is still there.

 

[MakkaPakka]

Definitely not out of phase and two sets of speakers were checked multiple times. Although I've said the speakers were the same volume, it's possible that the left one was louder but it was too subtle for my phone app or ears to pick it up. It may be that the slight imbalance messed up the imaging which is after all a combination of right and left volume to trick the brain. I'm just curious as to how you can get a very subtle imbalance which only seems to kick in at the speaker terminals. I tested everything I could and ruled everything else out.

edit: annoyingly I went back to 'A' one last time and it worked fine. This would suggest it's not the speaker terminals and is something else further up the chain and is, as had been the case previously, an intermittent problem.

 

[sheggs]

Where are the speakers placed in your room?

This can actually be caused by first reflections points. In basic terms what happens is that a sound bounces off a side wall and enters the ear a split secod before the direct sound. Your brain cannot distinguish between the two and you can end up hearing the right speaker in your left ear and believing it is the left speaker you are hearing

 

[MakkaPakka]

That could be happening had i not covered them in gik products

Has to be an amp as happened with two sets of speakers and intermittent - was fine all last night.

 

[MakkaPakka]

That could be happening had i not covered them in gik products

Has to be an amp as happened with two sets of speakers and intermittent - was fine all last night.

 

[MakkaPakka]

That could be happening had i not covered them in gik products

Has to be an amp as happened with two sets of speakers and intermittent - was fine all last night.

 

[sheggs]

Ha ha probably be perfect then :rockout: