AES output "hit" from certain actions in 7.1cs8

[BrianM]

I've recently upgraded to PT|HD7.1cs8 (from a MIX 5.1.3 system) and I've been experiencing a full-scale "hit" that occurs out of all of the digital outputs (AES) of the system when I do certain things with the software. For example:

[1] When I first start ProTools (2 hits, one early in the startup process; one as it finishes)
[2] The first time I open a session after starting ProTools (not on subsequent sessions)
[3] Everytime I add a new AVID Video Track
[4] Everytime I add a QuickTime movie to the session (whether there was one already or not)
[5] When I quit ProTools

These "hits" are full-scale and are coming out of ALL the AES digital outputs, which is quite painful (and surprising the first time it happens!).

Some details about the system:
-------------------------------------------------
PT|HD-3 7.1cs8, running on a G5 dual-core, 2.5GB RAM, OSX 10.4.6, PCIe
w/ SIIG FireWire 2-port PCIe for audio storage

Peripherals:
- ExpansionHD Chassis
- Avid Mojo (using additional interal SATA drive)
- (2) 192 I/O using AES input/output only
- Sync I/O (locked to AES sync output from console)
- Glyph GT103 Firewire Chassis (3 audio drives)
-------------------------------
The PT system (Sync I/O) is getting AES sync from the console (an SSL Avant), which gets it's sync from a composite sync generator that is locked to our house reference. I've switched the Sync I/O to "Video Ref" (which is also hooked up), but it didn't make a difference.

I'm not inclined to think that the console's AES inputs are the problem since a) it's not happening outside of these instances, which can be reproduced, b) they worked fine with the 888's that were used with the old system, and c) the same problem is also happening in another room in our facility which has a similar system connected to a completely different console (Sony DMX-R100). I have tried to set them to SRC, but it did not help.

Has anybody else experienced this? Any suggestions to fix it?

Thanks!

- Brian

[jakemoss]

I've seen the same problem with ADAT outputs:
HD2 (6.9.1) digitally connected to an SSL MT+
SYNC I/O set to Video Ref

I can live with the full scale noise when Pro Tools first boots up (I figure it is the SYNC I/O beginning to lock) but why the noise when you import quicktime movies?

[DigiTechSupt]

Does this happen when the clock source is set to the Sync IO?

[BrianM]

>>Does this happen when the clock source is set to the Sync IO?

Yes. In the Session Setup window, Clock Source is set to "Sync I/O" and the clock reference is AES/EBU. We've changed the clock reference to "Video Ref" but it didn't solve the issue.

- Brian

[DigiTechSupt]

I should have said 'with the clock reference to internal/vso'.

Does it still occur with that setting?

[jakemoss]

In my case, clock source set to SYNC I/O, SYNC I/O set to video ref, not internal.

[BrianM]

>>I should have said 'with the clock reference to internal/vso'. Does it still occur with that setting?

Yes. With the clock reference set to "internal/vso", all of the problems still occur.

- Brian

[BrianM]

Some good news:

On the advice of Brian Dozier, we removed the "Loop Sync" cabling and connected the Sync I/O to the 192 interfaces with "Word Sync" - i.e. "Word Sync" out of the Sync I/O, into the first 192, then out of the first 192 and into the 2nd 192, then terminated the loop at the 2nd 192.

It immediately cured the hits that were happening the first time I open a session after starting PT (#2 above), creating a new Avid video track, everytime I add a new AVID Video Track (#3 above), everytime I add a QuickTime movie to the session (#4 above), and when I quit ProTools (#5 above).

We performed the same change to the other system in the facility and had the same success.

The only one that's left is the initial hit that happens when I launch the ProTools application, but that's something I can live with since I do it once a day.

- Brian

[BrianM]

One last thing:

After switching over to Word Sync between the Sync I/O and the 192 interfaces, I noticed "hits"from the last set of eight AES outputs (on the second 192). They occurred at a regular interval and were higher in level on the middle outputs (4,5,6) than the outer ones (1,2,3,7,8).

In order to prevent it, we went back to having Loop Sync hooked up between the Sync I/O and the 192 interfaces, but also have Word Sync (from the Sync I/O) going to the first 192. This still seems to solve the problems we were having, such that the only output hits that we get on the AES outputs happen when Pro Tools first starts.

- Brian