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
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?
If you switch speaker cables and the problem switchs speakers then....it is not the speaker. If the problem doesnt switch then....it is the speaker(unlikely) or one of its cables. Try this first. Put everything back as before.

Then, remove the inputs from the amp, if the problem persists then....it is the amp. If it does not, replace the inputs on the amp and begin removing source inputs from your Preamp. One at a time, then power up and listen. Whenever the problem does stop the last piece disconnected and its cabling are the culprit. If you disconnect all the source inputs and the problem persists then...the culprit is the Preamp, to make sure, disconnect the inputs to the amp again.

A pain in the butt? You bet. But process of elimination is the most sure fire method. Good luck.
Carefully examine the placement of all your cables. It's possible that a single cable is picking up inteference from a nearby source.

Practically speaking you do not have a problem. From what you've written the noise is only apparent if you position your ear 1" away from the speaker. At that distance many if not a majority of systems will exhibit some noise.