Axiom Home Page Forums General Discussion Home Theater Center channel alignment test?

Does a test for center channel alignment exist on any of the test DVDs or CDs out there?

The reason I ask is that my TV is on wheels, and my VP150 is on top of it. Yesterday, I moved it about 18" to the left while rerouting my cables. I turned on the TV before putting it back in it's original position. The AVR was set up for Logic 7 Movie mode. I was flipping channels, when it ocurred to me that voices were sounding very strange. It could best be described as sounding very laid back. Like I had moved the center backwards instead of sideways. I tried some music. It sounded very "muddy" in the middle. I pushed the TV back where it belongs, and now everything is perfectly normal again.

It makes sense. The 2 mains build a nice, wide, stereo image that seems to come right out of the center channel speaker. If the sound coming out of the center doesn't align properly with that image, a muddy mess is the likely result.

You would think that Avia would have some sort of tones that "sync up" when the center aligns with the stereo image. Something like tuning a guitar.

I played a CD in stereo, noticed were the center of the image seemed to be, and centered the center on it. It sounds great, so I'm sure it's close. Part of me wonders how far off from "just right" it is...

Hi Michael_A,

Seems to me you did a pretty good job on your own of center-channel "alignment." I don't know of any particular discs that address this, but your technique of playing the stereo disc, noting where the center image is, and then aligning the center speaker with it seems to be excellent.

By the way, your discovery of how different your VP150 sounded in a different locations just backs up what I'm always trying to hammer home--that simply moving a speaker a few feet in a given room may introduce quite dramatic differences in the speaker's sound.

Indeed, in multiple tests of speakers which I participated in using scientific double-blind techniques, the same speaker would often be ranked very differently just by moving it to a different position (or if the listener moved to a different chair in the room). To average out these effects, we would judge each speaker in each one of four locations in the room, and from each of five different seating postiions. This would take days of listening, of course, but it proved to be extremely reliable and repeatable with any set of listeners with normal hearing. In other words, good speakers would receiver virtually identical high rankings from different listeners and bad speakers would get similarly low rankings, the upshot being that people with normal hearing tend to agree very consistently on what constitutes "good sound" and "bad sound".

Regards,

Oops, I seem to be chasing Alan around... my apologies.

As simple as it sounds, I find the easiest way to find a centre (whether centre channel or setting a rough pan in a stereo mix) is to close my eyes, shake my head a bit to disorient myself (not like a Stevie Wonder head bob!) and point to where I hear the mix coming from, open your eyes and see how far off you are and adjust. It works for me because I've got nearly identical hearing in both ears (despite spending about a tenth of my adult life wearing a left-ear-only ClearCom) - your mileage may vary.

Bren R.