Robot voice fault-PT HDX

[JohnRivers]

I'm running a late 2013 new Mac Pro OS 10.10.4 with PT 11.3.1 HDX, Sonnet expander chassis and Avid HD interfaces. Ever since I got this rig I've had intermittent problems. This fault is only evident on playback so imaging the night mare when recording long chunks of speech with an expensive actor!
Attached is a screen shot. I was recording a 40Hz tone via an aux channel with a DSP / BF76 compressor inserted. You can see the modulation and interruption to waveform.
The fault happened after 23 mins recording. There is no audible indication on the monitors, the fault is only evident on playback.
I've swapped the interfaces, at the insistence of Apple upgraded to 10.10.4 all to no effect.
Help!!!

[ThierryGauthier]

Hi

I have the same problem since 2 years with HDX card but I have a early 2009 Mac pro (no sonnet expansion). I try everything except erase and reinstall all the mac-system. The problem was there with PT 10 and follow with PT 11. Now on Mac OS 10.10.5 with PT 11.3.2. Problem persist. I have to change the buffer setting for the problem to stop, but it always come back after some time… Did you fix it? When I have the time to try total reinstall, Ill post the result...

[ThierryGauthier]

The problem is not solve with a clean reinstall of Yosemite and Pro tools only. So it seems to be a hardware issue, maybe Swap PCI card order. Troubleshooting this problem is a very long process...

[Chief Technician]

I have experienced this problem once. Did any of your tracks have input monitoring enabled?

[ThierryGauthier]

Hi Chief Technician,

Yes I use input monitoring almost all the time… Why do you think it can be the cause?

[Chief Technician]

Originally Posted by ThierryGauthier

Hi Chief Technician,

Yes I use input monitoring almost all the time… Why do you think it can be the cause?

Yes, I think the occurrence of this issue is related to having input monitoring enabled on tracks that you are also using for recording. Was your robotic sounding audio recorded on tracks that had their input monitoring enabled during the record operation?

[ThierryGauthier]

I did fix this problem, some time ago (sorry for the delay). I switch The PCI slot with other card and its perfect now!

[PTS]

Hello!
Yes, as mentioned already, I've seen slot order of the HDX card cause this problem but mainly on PC's, I don't recall seeing that on a Mac (but anything's possible).

Also, it could be a bad HDX card. Have you run Digitest on the HDX card?

Digitest may or may not show a problem so the best way to test it is to swap out the HDX card with a known good one but this isn't always easy to do.

Jon
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