How to check if digital audio is leaving the HD IO coaxial?

[snowplaysmusic]

Hi, I have an Avid HD IO connected to a Grace m905. I hear the balanced outputs from Pro Tools just fine. I have a Coaxial digital cable from HD IO to the Grace digital in. In the hardware setup, I have the Digital Format as S/PDIF. Sound is leaving Pro Tools into the Grace (I can monitor the balanced connection) but when I toggled to the S/PDIF I do not hear anything. I am not sure if the issue is the Grace or the HD IO, but I have no proof that any sound is travelling through that coaxial cable. What might I do to troubleshoot this? I have tried a second cable with no luck.

[Darryl Ramm]

You test it by connecting something like the Grace monitor controller you are using... or you test the Grace with something else. Pick simple, like an old CD/DVD player or portable music player with S/PDIF out as a source.

Has this *ever* worked? is it a HD IO you purchased new? Or say is it a new to you used unit?

...but it's most likely user error, so have you read the manual for the HD IO and the m905?

What is the clock source for the m905. Is it telling you it is locking to that source?

What other cards do you have in the HD IO?

You can also post screenshot of the exact HD IO setup screens you are using here. Post enough info on your session so folks know what outputs exactly you are changing to S/PDIF.

And the silly question... you really have m905 with Digital IO? You are not using the RCA input ports on an analog only unit? (sorry I know somebody who mistakingly ordered an analog only unit... thinking it was a bargain.).

You can/should test all of AES/EBU, S/PDIF over TOSLINK and ADAT over TOSLINK into the Grace.

[albee1952]

You might also post a screen capture of the hardware setup. It might be a case of the SPDIF output not being properly assigned(either in the Hardware setup, or the IO setup). How well-versed are you on assigning those things?(they can be very non-intuitive)