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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
 
I spoke with the speaker manufacturer today, and learned a few things.

1st, the panels are hand formed, and can vary in curvature. Accordingly, there is a special procedure used when setting the toe in which will compensate for the differences in curvature. The way I set the speakers up, using the lower cabinet, can result in a difference of toe in on the panel.

2nd, my speaker can vary as much as 1.5db from the other and still be considered "in spec" This was very surprising.

I will try the revised set up instructions and report back. More confusion.
rlips OP
105 posts
 
I implemented the toe in procedure recommended by ML, and found a Huge improvement. Balance is now dead
on, speakers are symetrical in the room.

As a side bonus, the new toe in has nicely opened up the soundstage, which now extends wider and deeper.
geoffkait's avatar
geoffkait
14,147 posts
 
Just in case you haven't tried this, track 3 on XLO CD is the best channel balance and soundstage focus track (assuming you do not have a problem somewhere along the line). The objective of the Out of Phase track 3 is to obtain perfectly diffuse sound in the room as heard from listening position - i.e., the sound should appear "to be coming at you from all around the room." In order to obtain this perfect focus/balance you need only to move one speaker a little at a time, i.e., you cannot necessarily rely on speaker symmetry, etc. to obtain optimum results. An inch or so movement of one or both speakers can make all the difference.
rlips OP
105 posts
 
Geoffkait,

Yes, I have spent a fair amount of time listening to that one. It is very helpful.
geoffkait's avatar
geoffkait
14,147 posts
 
You're prob. not going to want to hear this one, but IMHO the panels - even one or two - can have dramatic (negative) influence on the sound - esp. soundstage, balance, transparency. I always prefer the sound w/o any panels in the room, tho' I really wanted the panels to be "magic."
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