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Posted By: donjuanmiguel Surround Confusion - 09/29/05 11:16 PM
Hi fellow Axiomites. Hopefully someone can help me understand what may be happening with my surround system. Here is the setup:
Sony entry model DVD player (came with TV)
Denon 3805
4 In-wall speakers (installed by previous owner)
Sony HTIB center channel speaker (bought in '98)
3805 & DVD player hooked up via audio coax
Video sent directly to LCD via components

I've calibrated the 3805 and speakers using the auto eq and spl meter. Then for grins I used the THX audio optimizer. The first thing I noticed was the lag between osd and the signal sent to the speaker. The osd was a speaker ahead. The next thing I noticed was sound coming from the center channel speaker while the surround left speaker was tested. The same thing would happent when signal was sent to the back speakers.

I took the disc downstairs and played it on the axiom system, which uses a Denon 4806 and a 3910 linked via Dlink. There was no delay and all signals played as they should.

I'm thinking its either the coax hookup or the dvd player but in reality, I don't understand what's happening.

Please help an old rookie.
Posted By: Ajax Re: Surround Confusion - 09/30/05 12:03 AM
It's the DVD player. I have an Oppo that does the same thing. I'm not technically oriented enough to explain it to you, but it's nothing to worry about. When the THX demo starts at the left front speaker, the video signal is up-cut or isn't strong enough to lock in, and the OSD jumps to the center speaker, while the audio stays in the left front. It stays out of sync all the way around the cycle until the last speaker in the cycle (subwoofer?) when they link up again. Let it go all the way around the cycle and watch closely. After they sync up again at the subwoofer (or whatever the last speaker in the cycle is), the cycle will start over, and you'll see the OSD go to the left front for just a fraction of a second before it prematurely jumps to the center channel. Weird.
Posted By: donjuanmiguel Re: Surround Confusion - 09/30/05 12:52 AM
John, thanks for the info. Any ideas as to the center channel plays signals that are meant for the back speakers?

During movies I can't tell if the signals are getting crossed. Since the player only offers multichannel playback via coax, there is no way for me to test another connection other than left/right audio.

Any other suggestions/ideas?
Posted By: Ajax Re: Surround Confusion - 09/30/05 02:56 AM
Well, I can't speak for YOUR DVD player, but it is the way my Oppo reacts to the THX test that is the problem. In fact, when you run the THX test, it is the video that incorrect, not the audio. As long as you have the speakers properly wired to the receiver, all signals should be going to the proper speaker. If your receiver has internal test tones, you, easily, should be able to confirm this.
Posted By: dllewel Re: Surround Confusion - 09/30/05 08:11 PM
That sounds pretty strange, my first thought is that the speakers are not connected to the proper outputs on the back of the amplifier.

I have gotten a left and right crossed in the past and the test tone quickly identifies the mixup, could the wires just be connected wrong on the back?
Posted By: donjuanmiguel Re: Surround Confusion - 10/01/05 12:53 AM
That's a good suggestion. I checked and all is well. Using the 3805's channel level tests I confirmed the setup. I haven't had a chance to test further but I'm thinking either the player or the coax in not sending clean signals. I'm hoping to check it further next week.
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