Is there different audio delay when using coaxial and optical cables?
No, there is no difference in delay between optical and coax digital audio. The sync problem is in your receiver and/or display. The frame interpolation feature of some TVs and projectors (aka smooth motion, 120Hz) is usually responsible for the delay in displaying video. You need to add an equivalent audio delay to compensate. The sync feature on your player should do it, or you can set it on your amp, if it has a delay setting. Getting the delay within 10ms is really close enough, you can’t perceive a delay much shorter than that. Keep in mind there’s a delay of almost a millisecond for every foot between a speaker and your ears. Some calibration discs (such as GetGray) have a lipsync test, or you can find a scene on a disc (e.g., a door closing) and calibrate using that.
