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Please help, obsessive audiophile question

Ok, I did something really bad to myself, I got the XLO test CD. What I discovered was a channel imbalance, that, I think, is due to my room. Here is what I did:

First, using a laser, I perfectly centered my speakers in the room, and dialed in an equal amount of toe in on both sides. Also, again using the laser, I checked for dead center on the listening position and dead centered the components between the speakers.

Next, with the balance control centered, I ran the 315 khz test tone on repeat, and measured the voltage at the amp terminals. The voltage was nearly perfectly even. I repeated this at several volume levels, and usually was within a few percent. What ever variation occured between the channels was randomly split between left and right.

Next, the balance test on repeat. With the lights and my eyes closed, I used the remote to adjust the balance on the preamp to center the voice. I started out in the centered, extreme left and extreme right positions, and did my best to make sure I was unaware of how much adjustment I was dialing in. I repeated this multiple times, and got perfectly consistent results. I end up with the balance control turned about 4 "taps" to the right, which translates to a 10% voltage in favor of the right channel at 315 khz. I do not have a sine wave generator or ocilliscope, so I can not verify this over multiple frequencies, but my "aural" measurements have proved to be very consistant.

I adjusted a few moveable items in the room, but, due to some furniture that can not be moved, I think I am getting more reinforcement from the room on the left side.

So, what to do? Will this balance adjustment adversly affect my tube amps? Will one side go through tubes quicker? Should I try to move one speaker back? If I do move the one speaker back, will I adversly effect the time alignment between the two speakers? Or should I stop stressing and just leave the balance control off center.

I know it sounds compulsive and weird, but it sort of bugs me to see the balance control not dead center. Again, this IS an obsessive audiophile question;)

Thanks in advance for all your thoughts.

Ron
rlips
rlips OP
105 posts
 
Rock: LMAO thinking about the driveway thing, yeah, my speakers and a couple hundred pounds of tube amps in the driveway. They would lock me away.

I am going to run the test tonight, my wife is going out with the kids, so I can happily stress out;)

R
chazro's avatar
chazro
575 posts
 

I suffer from this same problem and I've always made the adjustment with my balance control. This past year I made the leap to tubes. I've bought a Music Reference RM9 amp and a RM5 MkIII preamp and I'm lovin' em! I didn't realize that I was causing uneven tube usage until I read this thread. Can anyone elaborate? How soon will this problem manifest itself? Thanks to this thread I think I'm going to play with my speaker placement, I don't want to mess with my tubes!;)
buscis2's avatar
buscis2
468 posts
 
Balance control? I don't even have a front panel power switch.

Although the manufacturer was gracious enough to provide me a means in which to adjust the volume.
pmotz
375 posts
 
A couple of suggestions based on the photo of your system. Try swapping the plants from side to side to see if that shifts things. They are different sizes and the Martin Logans do have a significant back wave adding to the sound. The other thing is the construction of the room, based on the photo the front part of the room is very symmetrical (with the slight exception of the plants) but is the construction of the two side walls the same? If one is insulated and the other not or one solid (concrete or block) while the other is framed it can make a difference. These may seem like wild ideas but you've ruled out a lot of the more obvious things. With respect to items behind the listening position (out of the photo) you could try adding some diffusion to eliminate reflections that could be reinforcing or cancelling specific frequencies. Your comments on how the tube trap improved things indicates that could be a problem. A small room could emphasize this problem, what are the dimensions of the room?
rlips OP
105 posts
 
Pmotz: I tried the plant thing, and it helps somewhat. It does not get rid of all the problem. The photo represents plant placement before the tweaking, they are now reversed.

The left wall is an exterior wall, and is insulated. The right wall is an interior wall, and is the same construction, but not insulated. This could very well be an issue. It is frame construction, but the exterior wall would have drywall, insulation, plywood, stryofoam and siding. The interior wall would have drywall, airspace, and drywall.

Thanks for you ideas, they may be helpful....."honey, we have to tear down some walls now" Actually, at this point, she would just laugh.

Best,
R
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