Originally Posted by jdsmoothie
Most HDTVs going back at least 5 years have optical outputs. The newer HDMI 1.4 AVRs with ARC simply save the owner from having to use that extra optical connection, however, the audio quality is the same either way whether it's going over optical or back over the HDMI cable.
Unfortunately, on many TV's, the sound available is more limited than you might expect. Almost all TV's can be set to transmit Dolby Digital from their tuner inputs. However, many of them will transmit only stereo even if an HDMI input is carrying a digital track. When that is true, digital sources (even if that digital source is only Dolby Digital) should always be directly connected via a digital sound output to the receiver rather through an HDMI port on the TV.