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Want to Blow Up My Stereo

If anyone has ideas as to the culprit of my issue I'd sure love to hear it.

For I don't know how long I've had an issue with my stereo putting the center of the image just inside the right speaker. This week I decided to "fix" the issue, and began trying everything I could think of. I had previously tried all the usual suspects: swapping the left and right interconnects, swapping the speakers, changing speaker positions. I've added a preamp (no effect on this issue), changed CD players, interconnects, and speaker cables. I thought for the longest the issue was the 24" dropoff in depth of the back wall, as the sound "pools" just inside that dropoff. But this week I've tried even putting the stereo on the flat, long wall instead of the short wall. I've also tried reversing the polarity of the interconnects and the phase on the preamp. (As an aside, reversing the polarity of only the interconnects from CDP to preamp resulted in a mirror image of the image shift, but the sound was very diffuse with no bass at all, and inverting the phase on the preamp had very little effect on the sound.) I've tried moving my room treatments (GIK absorption panels and Echo Busters diffusers) with very little if any effect. I tried moving the speakers completely against the side walls, very close together, and with the left speaker 3 feet closer to the side wall than the right. The image doesn't move. I just want to take a sledgehammer to my entire system. I haven't built a (I don't even want to think about how much money) ridiculously expensive system by sane person's standards (just ask my wife) to have some stupid issue like this that doesn't exist with my "normal" investment home theater.

And if you had any idea how many times I've had to edit this post to remove foul language and inappropriate phrases I think you'd feel my pain a bit more...or maybe not.

At any rate, please help.

Link to system: http://forum.audiogon.com/cgi-bin/fr.pl?vdone&1258245716&view
aggielaw
tpsonic
1,092 posts
 
The most important thing one of my mentors had said to me:the visual center and acoustical center may occur in different places.Think of setting up the speakers,as three different "planes" (not aero).Left,center,right.Left will control that occuring L-speaker outward.Same with right and the center is summed L+R (adj for image focus and proper weighting in the bass).One speaker will anchor the soundstage.Then finding the appropriate "other" may be easier.The final set-up may not be symetrical (as mentioned above)IE:toe-in,distance from back wall.
Try starting out with no absorption-this can lead to shorter image height or pooling of the sound.Any absorbative material should be up in the corners-if a must.
Where are you located?? As I'm sure a fellow member would be willing to lend assistance.Tom
rhljazz
1,117 posts
 
How is it possible to reverse the polarity of the interconnects from the CDP to the Pre? You should only be able to swap channels, not polarity, and if swapping channels did indeed move the imbalance to the other channel there must be a problem with the CDP. I have a test disc that plays image positions for: center, left center, left speaker, and far left. This is repeated for the right channel. I could look up the title and number if you are interested.
cyclonicman
693 posts
 
Sounds likje you tried everything. It almost sounds like the balance is deliberately favoring one channel. Do you even have a balance control? Are you sure that all of the speaker drivers are working properly. Maybe you can try a different pair of speakers just to see if you get the same result.
mapman's avatar
Ag insider logo xs@2x
mapman
15,679 posts
 
Don't do it.

If you do, be sure to use audiophile grade dynamite.

Just kidding.

Seriously, I suspect room acoustics. Sonic center often does not equate to visual center as someone above noted, especially with speakers that throw a big holographic soundstage. I have the same issue with my L shaped room where my OHM f5s reside.

Did you get exact same imaging results placing the speakers along the alternate flat wall in regards to center of image or did it move somewhat?

One solution: if everything else sounds fine but the sonic center is shifted slightly, so what? Train yourself to ignore speaker location an just listen to what you system and room is giving you.

Attenuaters in-line on one channel is another option I would think. I have and have used attenuaters but never to affect channels differently.

Toe in of the speaker farthest from sonic center for more direct exposure at your listening position (or toe out of the other for less) is another option to shift the sonic center.
almarg's avatar
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almarg
8,673 posts
 
Have you ever not had this problem with these speakers?

I can't formulate a theory that fits all of the facts that you have stated, but I'm wondering if one of the speakers might have the connections to one of its drivers or one of its crossover elements reversed. Since the crossover is nominally at 1700Hz, with third-order rolloff, a miswire resulting in partial cancellation of frequencies in the crossover region could pull the image toward the other speaker, since it is mid-range frequencies that would be affected.
As an aside, reversing the polarity of only the interconnects from CDP to preamp resulted in a mirror image of the image shift, but the sound was very diffuse with no bass at all, and inverting the phase on the preamp had very little effect on the sound.
A diffuse image combined with attenuated bass is an almost certain indication that the two channels are out of phase relative to one another. When you say you reversed the polarity of the interconnects from cdp to preamp (and I assume you were using balanced interconnects), do you mean that you interchanged xlr pins 2 and 3 simultaneously on the cables for BOTH channels?

If not, and only one channel was reversed (either inadvertently or intentionally), that would certainly explain the diffuse image and attenuated bass. On the other hand, if you truly reversed the phase on both channels, and the result was that the image moved to the opposite speaker, and simultaneously became diffuse with attenuated bass, perhaps (and I'm just guessing here) there are two inter-related problems present, such as a miswire in a speaker combining with asymmetrical room effects, resulting in confusing symptoms.

BTW, the polarity switch on the preamp is undoubtedly an absolute phase reversal function, which would invert both channels simultaneously. That would result in effects which were either very subtle or non-existent, depending on the recording. I can't explain, though, why flipping that switch gave different results than interchanging pins 2 and 3 on both interconnects, unless I've misinterpreted something in your post or you inadvertently had pins 2 and 3 interchanged on only one channel.

Hope that is of some help.

-- Al
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