Audio out of sync - surround and tv

[festivus]

Just wondering if anyone else has encountered this issue and how they fixed it.

I got a new plasma and have it connected from my sat receiver via hdmi. I had the sat receiver connected to my surround via toslink. Since the center channel on my surround is not good, it's fuzzy, I use the sound from my tv to provide the dialog. (Yes, I know I need a new surround system but I'm putting it off...) It had worked pretty will with my old TV but with this new tv the sound was a split second out of sync. It produced an echo effect.

To fix this I changed the toslink connection to the surround to use the digital out on the tv. This seems to have fixed the echo but I now no longer seems to get the really high-quality digital sound that I had been getting when connected from the sat receiver. But it still sounds MUCH better than the echo.

I guess that my question is what causes this echo? Is seems that either the tv or the receiver processes the signal from the sat box faster (or slower). Anyone esle encounter this?

[zelig2]

The echo sounds pretty strange to me.

The reason you don't get high quality audio out of the tv digital output is because it's downmixed to stereo at the tv. It's fairly common for sets to take audio in via hdmi and then mix it to stereo since that's the only speakers the tv has. Kind of stupid if you ask me but is standard on most tvs.

[festivus]

Yeah, the echo was strange. Even if I used the rca left/right audio jacks into the TV instead of the hdmi audio I still had the echo with the surround system. It kinda sounded like someone talking in a big empty building when I had the sound turned on both the tv and the surround. This TV must be processing slower or faster.

Oh well.

[DublinDoodah]

I once got what might be described as an echo effect when I inadvertently had the sound enabled on my TV at the same time as my receiver.

[festivus]

I did some digging. This issue is related to the dreaded "lip sync" issue that can be found discussed all over the internet. New TVs are processing video (and in my case audio) slower than receivers are processing audio. When using only the receiver for sound the video is behind the audio by milliseconds.

The only way to fix it is to adjust your receiver to delay the sound. My dinosaur receiver has some delay adjustment available but it might not be enough to fix the issue. I'll have to check when I get home tonight.

[Scott]

Man that sucks!

[festivus]

Yeah, it really does. Especially since my receiver can delay the center channel by 5 milliseconds only. Not enough to get rid of the echo even if I were to use the fuzzy center channel.

So until I get a new surround system I'll have to go with the audio out from the TV. Could be worse.