Getting phantom image perfectly centered


This is driving me nuts! I can't get the image centered unless I turn the balance control on the preamp to the 1:30 position. I've tested the system from source to loudspeakers from an electrical standpoint, so I know each speaker is getting the exact same electrical signal with a test tone and each speaker outputs the same dB with the same test tone.

So, it HAS to be the speaker room interaction, right?

I've read http://www.linkwitzlab.com/listening_room.htm and I THINK I understand everything.

All of the following measurements are in inches:
The room is 189 long by 144 wide. (15.75 feet by 12 feet)

The speakers are precisely 45.5 inches from the back wall.
They are each 26.5 inches from the side walls with a caveat. The left speaker is 27.5 inches from the window sash, which is 1 inch deeper than the wall. It's 30 inches to the top panes of glass and 28 inches from the lower panes of glass. But measured from the actual wall, both speakers are exactly 26.5 inches from the wall.

The speakers are precisely 90.5 inches apart.

The listening position is pretty close to 45.5 inches from the back of the room. The back of the room is open to the rest of the house and the wall on either side of the opening is symmetric with each partial wall being 36 inches.

Listening to a recording were I know the voice is dead center, the voice is actually just to the left of centered, and I mean "just". Would you recommend moving the left loudspeaker towards the center an inch or two?

What kinds of techniques to you use to "dial it in" when you've got a really revealing system and you are past the "math" and it's all more art than strict science?

I think you should be able to see a picture of my listening room here: http://orion.quicksytes.com/download/file.php?id=3096

My apologies if this isn't the right sub-forum to post this question to.
marktrav

Showing 2 responses by bmwmcab

I've been in your situation before and it also drove me nuts! What i did was just make sure everything is symmetrical - speaker to listener, centered between both speakers, etc. When you got all that down, play with the toe-in to dial it in. If your image is to the left, start toeing in the left speaker by a couple mm and the right toe out a couple mm. Just do really minor toe-in movements and eventually you will find it like I did. Good Luck!
Weebeesdad,

That's also what I thought at first but through trial and error, I found that this method actually worked for me. If the image is not perfectly centered, it really bugs the heck out of me and I would try many things to correct it. The up and back method works to a certain point but it hinders the harmonics and tones. Ymmv.