Avid Fast Track C400 SPDIF loop not working

[miezurecords]

Hey guys,

I just bought a C400 interface and I wanted to set it up like so:
IN 1: Mic 1
IN 2: Mic 2
IN 3-4: SPDIF <<< coax OUTPUT from a TC HELICON VOICELIVE 2 processor

OUT 1-2: Monitor Pair 1
OUT 3-4: Monitor Pair 2
OUT 5-6: SPDIF >>> coax INTO the TC HELICON VOICELIVE 2 processor

I'm using ProTools Standard 9.0.6 on Mac OS X 10.8.3.

Here's how I have stuff setup in my DAW:
Screen Shot 2013-07-10 at 9.58.01 PM.jpg

Screen Shot 2013-07-10 at 9.58.17 PM.png

Screen Shot 2013-07-10 at 9.58.26 PM.png

Here's the setup on my TC H VL2:
20130710_220132.jpg - I've rocked the DIG OUT TRIM all the way from -12 to +12, so that's not the problem.

What I'm doing:
Arming Audio 1 and Audio 2 for recording and clicking rec.

Expecting:
Audio 1 should have the Dry sound
Audio 2 should have the Wet (TC H VL2 processed) sound
Same applies for inserting a clean voice track on Audio 1, record enabling Audio 2 in order to get the Wet (TC H VL2 processed) sound.

Actual situation:
Screen Shot 2013-07-10 at 10.07.30 PM.png
Audio 1 sends to the TC via OUT 5-6 (SPDIF) and I can hear that signal is
received and processed by the TC, because I've got a pair of M50s hooked up @ the analogue HP output of the processor.

And here's what the TC Helicon VoiceLive 2 User manual specifies:
"SPDIF digital output is always available regardless of
DIGITAL IN or OUT settings."

But, as you can see, there's nothing coming into the SPDIF IN of the audio interface... I can't pinpoint the problem. Do you have any suggestions on this one?

TC H VL2 is using firmware 1.5.05
Avid C400 is using Package 1.1.2, firmware 1.0.1

Do you have any suggestions on how to check which of the SPDIFs is not working and/or what might be the problem here?

Thanks,
Mihai

[miezurecords]

Ok, so I managed to make the loop by setting the clock source SPDIF in the interface's menu.
Works when testing with the C400's Control Panel app, in spite of some minor clicks and pops.

Issues:
The TC processor only supports 48k sampling rate when it's being used as a master clock.
When I start ProTools, the whole machine almost freezes and the audio interface freezes as well. I have to turn off the TC, unplug and replug the interface and, only after that, I can use it again...

The only viable solution I have is:
Record through the interface and at mix-time plug the processor's analogue RETURNS into the C400's analogue inputs while still using the interface's SPDIF out for SEND.

So, i guess it's a sync issue. Any suggetions? :)

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