I was recently asked about a problem getting good sound out of a fairly recent audio video receiver connected to a new flat panel TV and using a Rogers digital box and a Sony PS3 player.
They had connected the Rogers box and the PS3 directly to the TV and used the TV’s fibre optic output for the audio signal back to the digital receiver.
Digital audio video receivers are designed to be the central distributor for all signals in today’s digital theatre world. In most cases they are equipped with two or more HDMI inputs and at least one HDMI output to connect to the TV. Most TV’s do not send the surround sound component of the audio fed into the TV by a HDMI cable. The reason for this has to do with the digital copy protection (HDCP) that all manufacturers have to adhere to these days to prevent digital duplication of digital audio and video signals. Once the TV has received an unaltered HDMI signal from the source device it does not send the audio back out without alteration – it turns it into stereo sound and in some cases (some protected Blu-ray discs) it will refuse to output audio from the fibre optic (toslink) output entirely!
A Digital audio receiver is a little differently designed, in that it can receive the audio and video signals from the HDMI input, extract and process the audio the way it was meant to be heard and because the HDCP circuit realizes that the Digital receiver cannot in itself show you the picture the video signal is passed along unaltered to the TV.
A lot of Blu-ray discs are using Dolby Tru HD and DTS Master Audio. Both of these systems use higher sampling bit rates resulting in as close to the theatre sound at home as we can get (so far). A lot of the new audio video receivers have the capability to play this soundtrack. When the source componnent is not hooked up directly to the audio video receiver via HDMI you will NOT hear these audio improvements in Blu-ray sound. 🙁
More on DTS Master Audio and Dolby Tru HD in upcoming posts.
If you are in doubt, call us or send us an email.