Mac Pro distortion for firewire audio (duet, 002r)

[mtumi]

Hi -

First off, thanks for reading. I'm at the end of my rope on this one.

For the last 2 years (since I moved from a G4 + digi 001 to an intel mac + 002r) I have been experiencing intermittent distortion issues where the audio distorts periodically, sometimes for just a second at a time, but eventually permanently.

The fix with the 002r was restarting PT. I assumed it was a digi problem, until I replaced the 002r with an Apogee Duet and STILL have the same problem, even after installing 10.5 clean and deleting all Digi drivers.

The fix with the Duet is to change the format in Audio MIDI setup from 44.1 to another setting (doesn't matter which). Apogee has told me this resets the firewire driver. It's better than restarting, but still sucks horribly. Their support has been somewhat helpful (definitely more than Digi's) but not pointed me in the right direction yet.

This happens in Logic, but also happens in the OS, for example if I'm playing a quicktime movie or listening to iTunes. the regular audio port has no issues.

This has been driving me crazy for 2 years. If anyone can help I would be eternally grateful.

Setup details:

MacPro 1,1 (dual xeon 2.66)
3 GB memory
2 fast drives (on serial-ATA, not daisy-chained on FW)
duet (plugged into rear FW port) (and had same problem with 002r)
OS X 10.5.5

Logic Studio (but had same problem with PT)
Native Instruments Guitar Rig + Kontakt (but had problem prior to installing these)

Thanks -

Michael