Please help, obsessive audiophile question

Thanks for the responses so far, it helps to know there are others like me out there!

Fefer77: I think the gain is ok, as I measured the outputs of the amps to be fairly equal. I already switched the amps around, no change.

Electric_monk (great moniker, btw): I can't do that, I have really short cables, the advantage of monoblocks;) I will probably lug, but I will have to enlist some help, so I can't do it right away.

Deano: I might end up doing that, but I was concerned about messing anything else, as I have the rest of it dailin in nicely. I think I will try it though, as I can always go back.

G_m_c: I agree, but the question is, where exactly should I begin the cut? Do I cut off the entire thing, or try to balance it by just cutting a little at a time? Should I use a stainless steel knife or would that give the system a "metalic" sound? Should I cryo the ear? Sorry, I digress, but at least I am smiling now.

Oh, Feffer77, I missed part of your response. Behind my listening position is a semi round piece of furniture on the left side, and a solid core wood door on the right. I am pretty sure this might be the cause of the imbalance. I moved one of my tube traps in front of the furniture and it helped.

Some good comments above.

A small amount of channel imbalance that varies with volume is quite normal. Most mass produced potentiometers don't track both channels identically and will "wobble" back and forth slightly as the value is altered. If you want to fix this, get ready to install precision built hand assembled stepped attenuators.

The fact that you showed even voltages at the speakers says that the signal amplification chain is working relatively linearly. This leaves only three reasons for the imbalance that you are experiencing.

1) Room loading conditions are causing image shift due to various reflections and cancellations

2) One of your speakers is working differently from the other causing a variance in frequency response / imaging.

3) Both you and your wife have similar hearing disorders.

My guess is that it is probably either 1 and / or 2 with 3 being a WAY distant third. There is a very easy way to narrow this down. As mentioned above, you can try swapping speakers from side to side. If the balance remains tilted in one direction, it is the speaker / room acoustics interphase that is creating the problem. If the image shift reverses itself, you've got a problem with the speakers.

If the speakers are too large to move around and easily position by yourself, you might want to try doing a nearfield measurement using a frequency sweep to verify relatively even output across the audible band. Taking readings further into the room and away from the speakers may confuse the issue by the reflections / cancellations coming into play. Obviously, small variances from one speaker to the other are to be somewhat expected due to non-precision microphone placement from speaker to speaker. Rather than look for huge abberations, which you hopefully won't run into, keep an eye out for specific trends.

Until you can get things straightened out, i see no problem with using the balance control to maintain the proper center image. Just bare in mind that if you are running any tubes in the system, one side is getting more of a work-out than the other. This can be somewhat alleviated by swapping tubes from side to side after a given period of time, etc.... This is not that big of a deal for SS gear, but you could always swap cabling around in order to try and achieve "more even wear" if a long term situation.

If it turns out to be the speaker / room interphase, sound treatment panels can work wonders when properly applied. I just got done doing some major work on my Dad's system / room. I have gotten no less than three phone calls from him in two weeks just for him to say "THANK YOU" for all the work put in and the results achieved. I've still got a ways to go with his system, but now he understands why i always complained about how bad his system sounded, especially in certain aspects of operation. Not only did these efforts get him far better results with more consistent sound, it bought a lot more respect for my opinions and ears from him. Before this, i was just his big-mouthed older son. Now i'm his big-mouthed older son that should have taken care of these problems years ago. I might have done so if he wasn't so "pig-headed". To be honest, i was only able to make the changes that i did because he was away from the house for an extended period of time : ) Sean
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PS... The type of investigative research that you are doing is the first step towards obtaining truly excellent in-room response with great leaps towards transparency and improved sonics. I am glad to read of someone putting forth the time and effort that you are. I just hope you continue down this path as you will not regret it. Nor will your wife, even though you may drive her crazy initially : )

Sean,

Thanks for your post. I think I am going to lug my speakers around, to get to the root of this. I was trying to eliminate the idea that it might be equipment related, and, frankly, I did not really think that it could be a speaker output imbalance. If it does turn out to be an speaker problem, it should be easy enought to fix, as they are only a year old.

I will report back.

Believe it or not, i've listened to systems and found major problems that the owner's were completely unaware of. One system had a blown midrange driver in one speaker and another system had one of four woofers dead ( two woofers per speaker ). Neither owner was aware of this until i pointed it out. As such, it is quite possible that you could have a driver(s) that is completely dead or "softer" than the one in the other speaker. Someone else i know ran into something similar to your situation and after doing some testing, found that one of the tweeters, even though it was still working, was -3 dB's down from the other tweeter. Needless to say, he was quite shocked to find this out. Sean
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