Different sound between two channels


I have noticed recently that the sound of my left speaker is slightly different than my right speaker. The right channel appears to be brighter sounding than the left channel with the right channel sounding slightly richer sounding. I've tried reversing my speaker cables at the back of my Pass X250 and the problem kind of switches channels. I'm not sure if the problem is with my Hales T5's or the Pass X250. I think it may be a bit of both. I replaced the voice coils on both the tweeters of my Hales and the sound in general improved but the issue of the right channel being slightly brighter remains. The difference is noticable with the entire speaker as when I play just one channel or the other I notice this characteristic sound with the enire speaker. If my preamp is muted I will get a bit of residual noise from the amp in my right speaker(which is the brighter sounding speaker) and I imagine this residual noise is constant and may be causing the varient sound between the speakers. If anyone has any possible explanation or similar experience your feedback would be appreciated. I should mention that I spoke to Pass and they said it was normal for the X250 to be slightly different between it's two channels and that some residual noise in one of the channels is normal. I should also mention that what I'm experiencing is only noticable when listening right up to each speaker and is not noticable from my listening position.
128x128mitchb
To obtain a true full-spectrum mono (summed) signal from stereo disks, you could also insert mated 2-female-to-1-male and 1-female-to-2-male Y-connectors in the line between source and preamp, or between preamp and amp. I still don't like the Pass explanation of different-sounding amp channels as being 'normal'.
Goinbroke,
I like your user name. Been there, done that. I'll be paying for my stereo for a long time.
Yes, my speaker cables are the same length. Aren't everyones? My speakers are exactly the same distance from the side and front wall, my system appearing to be symmetrical. I have a rectangular room dedicated for audio which is why I would expect the channels to sound the same. In my old place I had the same problem but attributed it to the room as the room was uneven and of course the WAF. In my room now I have room treatment throughout with foam on the side walls and cushions in all the corners. I am beginning to think that maybe the difference I hear when close up to each speaker is caused by the same residual noise I hear from the right channel when preamp is off and my ear is an inch from the tweeter. At that point I hear a slight hiss from the tweeter and a little hum from the midrange(right speaker) but on the left there is no sound. If I listen from my listening position to a mono recording I get a good central image. I only notice the difference if I stand right up to one speaker and then go right up to the other speaker. The right speaker is less "clean" sounding more bright and a little tinnyish. Almost as if there is distortion in that channel. Sorry for the long post but it's quiet at work.
Hmmm...so much for being something simple. Since the problem moves from one speaker to the other when you switch the cables, I seriously doubt it is the speakers. Unfortunately, it sounds like the problem is something internal to the electronics and could be as far up the chain as the source. At least it's not audible at your listening position. If it really bugs you, you could have the system looked at by a qualified tech, but you would probably have to take in the entire system minus speakers to get to the answer. If it doesn't bug you that much, I'd suggest to pour yourself another glass of (insert favorite beverage here) and enjoy the music. Good luck.
Goinbroke,
I eliminated the source and preamp by manipulating the interconnects from them and have concluded that it is the amp. Pass claims that the residual noise I am getting from the right channel is normal and I think that it is this noise within the channel that may be causing the difference in sonics between the tweeters. What do you think? It does sound good when listening to music and perhaps I'm being a little fussy but perhaps not. Shouldn't a $9000 amp sound equal on both channels when putting through identical signals regardless of where I'm listening from?