Delay in sound from HDMI source - sound doesn't sync with video

[Phillip]

I am experiencing a strange problem. When my cable box or TIVO is tuned to a channel showing live TV, on some of the channels the audio is out of sync slightly with the video. Strangely enough, the audio is a split second ahead of the video, so you see that the mouth movements of the speaker lag behind the audio. I have the following rig:

Emotiva UMC-200 Preamp
Emotiva UPA -500 Amp
TIVO Roamio Plus
Time Warner - Samsung DVR
Sharp Aquos 52" HDTV

The problem only seems to appear on channels broadcasting a "live" signal (ESPN, local newcasts,) On prerecorded content, everything seems fine. Also, not every "live" channel always exhibits this behavior, although ESPN always does. As expected, the cable techs say it is a problem with my preamp, which makes no sense to me, but I'm open to changing my mind if someone can explain to me what is happening.

Any suggestions? Thanks very much for your help!

 

[Adam]

Welcome to the forum!

Have you tried changing the lip sync settings (under Menu:Setup:Input Setup)? I don't own that unit, and the manual doesn't list the options, but normally there is an "auto" setting for that. You can try changing that setting around and seeing if anything fixes it.

 

[Phillip]

Thanks for the info. I will give it a try. I wonder what "Auto" means in this context.

 

[Adam]

I wonder what "Auto" means in this context.

Me, too. All I know is that I leave it there, and things seem to work. Could be blind luck, but if so, I'll take it.

 

[Phillip]

Turns out there is no "auto" setting, just 'Off" and then increments of 1ms. I have no idea what to set it to so I'm just going to tune to a channel with the problem and increment the setting until the problem disappears.

 

[Grador]

For auto the theory is that the TV manufacturer can see how long it takes them to process/display the video signal and set this number internally. The receiver can then detect this number over HDMI allowing you to not have to deal with it yourself. I found the auto setting to be off by a few milliseconds for my TV and ended up setting it manually anyway.