[Thespinoy]

This post seems pretty old but I was having this same problem recently and found no answers on the boards, but I think I finally found the solution (knock on wood) for my system anyway.

Go to Setups > Playback Engine. Under the DAE Playback Buffer section, set it to Level 4 or higher. Mine was set to Level 2 (default). When I set it to Level 4, it fixed the white noise bursts right away and I didn't even have to quit and restart the application.

The white noise was driving me crazy. It was litterally happening about 15-20 minutes into a session and I would have to quit and restart PT just to have it happen again in another 15-20 mins. After I made this adjustment, the blast of white noise has not come back.