Digital audio question -- HOW CAN THIS BE??

[Diapason]

When I watch TV, I use the optical out of the TV into a DAC and play the sound through the hifi. I've been doing this for years, and lip-sync is always fine this way.

When I got my new amp, I did the same and all was well, still no lip-sync issue at all. However, I discovered that the TV doesn't play nicely with ESS chips and can lead to occasional sound dropouts (that's another story...) so I have been trying to find ways around this issue. I currently have my Bluesound node connected to a DAC input on the amp, so I thought I might as well connect optical out from TV into Bluesound and then from Bluesound to amp to see if that solved the dropout problem. It seems to, so that's good.

HOWEVER! When I do this, the sound comes *before* the picture. If it came after then that would make some degree of sense, but no, it comes before. And here's the real kicker, Bluesound provide a delay toggle in the app for exactly this circumstance, saying that you should toggle the delay on if syncing to TV. I can't wrap my head around it. TV direct to amp is fine. TV via Bluesound to amp leads to sound before picture.

Can anyone make sense of this one? It's really baking my noodle.

(It's all working fine, but the delay toggle apparently comes with a reduction in sound quality according to the app, so being a nerd I'd prefer not to have to use it.)

[Fran]

Is there adjustment for sync in the TV?

[Sloop John B]

Were you watching Doctor Who at the time?

.sjb

[dubber]

Presumably SPDIF has some sort of sync feature based on the source clock, perhaps the bluesound implementation is crap (I believe that's the appropriate technical term!)?