Pro Tools 10 Distorted/glitchy/High Pitched noise on Output

[zygmunt]

This problem revolves around Pro Tools suddenly, and randomly glitching out and making the output sound incredibly thin, distorted with high pitched noise. To describe the sound further, it's a cross between a bit-crushed and ring modulated effect over the whole mix, but doesn't sound as cool as what I'm describing

I've tried searching for this issue online, but haven't had any luck. For the record, I'm 99% positive it has nothing to do with the standard gain staging mistakes within pro tools. It's completely independent to any of these sounds.

I ran into this problem again last night when listening back to a session through my interface. I had not seen it since I first encountered it using pro tools stand alone on my macbook pro, but didn't think much about solving it since I hardly ever use pro tools without my interface. Now that it is happening through my interface i desperately need to solve this.

It's a major show stopper. I cannot predict when it happens, and the only way to reset the sound is to go back into the playback engine and re-select my metric halo as the output device...and then it happens a few minutes later. I believe I have had this issue on all revisions of PT10, as it initially happened on my laptop (without interface) when i was running 10.0.1, last night I tried 10.1.2 and 10.1.3. I've just done a FRESH reinstall of my whole OS, and I'm getting the issue both on 10.1.3, and then 10.0.0 when i resorted back to that.

I can rule out these factors (or so I believe):

1. Not a plugin issue. When i did the fresh OS install, I opened the session before installing any plugins and had the problem.

2. Interface - doesn't seem to be my interface as last night i was able to recreate the problem when playing the session through the OSX aggregate device setup. Not to mention, this is how I first encountered the problem a few weeks ago.

3. I thought sample rate might be an issue as at the moment it is only happening with a session at 96kHz. HOWEVER, the session I made when I first ran into this noise was at 44.1...Although it's strange that I am not getting it at the moment with sessions at lower sample rates.

4. It happens on all outputs (cans, monitors, laptop speakers), so none of these are the cause.

5. Buffer size - happens even at the largest settings

Has anyone ever seen (heard) this issue before???



Some info:
Macbook Pro 2GHz Core i7, 8 GB ram
OSX Lion 10.7.3
Pro Tools 10.0.0 at the moment, about to try 10.0.1
Glyph GPT50 External FW800 drive
Metric Halo 2882