I just added a tip to the
DP Tips Page regarding this. In fact, it's the first tip in the whole series, now, and it's pasted below:
SUPER HOT SET-UP TIP FOR CRACKLING AUDIO!
[Editor's Note: the following tip is something of a breakthrough for Digital Performer users at the time of its writing (August 4, 2005). Since we will be telling MOTU about this, it is hoped that before too much time has passed, this tip will be no longer necessary, and thus long forgotten, but for now it brings relief to those who have been pulling their hair out over this bug. I have tested it thoroughly and added some info to the original tip, but all credit goes to our fellow forum member, qo, who pursued this problem until he found the answer! Cheers for qo!
Category: Setup, bug work-around
Unexplained Pops and Clicks in audio
Works in: Audio/MIDI Setup version 2.1
Unexplained crackling and pops in live audio through DP (as well as Soundbite auditions and some other audio) that just won't go away no matter how you set things up were a major annoyance for some users. It seems to affect those who use more than one hardware and/or software interface simultaneously. It has been shown that this has occurred inconsistently since DP version 4.0, and it has affected a variety of audio interfaces, including:
••• Apogee AD-16X & DA-16X,
••• M-Audio Firewire Solo,
••• MOTU 1296
••• MOTU 896
••• MOTU 2408 mkII
..and probably most or all others. It happens on most or all models of Macintosh. There are some versions of DP in which it apparently is not a problem, but since approximately DP version 4.52 it has returned to plague even those who did not experience it earlier. Nothing seemed to help. Until...
I created a "CoreAudio Aggregate Device" in Audio/MIDI Setup, and selected it in the Hardware setup panel DP. Crackling audio is history. 100% gone. Vamoosh. Demons cast out! I have no idea why this would be the case other than it must be changing how DP interacts with CoreAudio. But, it does work.
Note: Clicks/pops still rear their heads, but they do so appropriately, as in when DP's CPU Performance meter maxes out, or when certain setup parameters are changed on the fly. To solve this, the standard sorts of things apply (increase buffer size, freeze tracks, etc).]
1) Go to
Audio/MIDI Setup, Apple's utility for managing your Core Audio and Core MIDI ports and connections. Click on the Audio side in the buttons at the top of the window.
2) Look in the Menu Bar to open AUDIO ••â€
) The buffer overrun sounds more logical. But this much I can tell you: This is a major discovery. When so many of us have tried so many things, pulling our hair out with clicks and pops, and worrying silly over it, the solution that just fixes it cold with no exceptions has GOT to be a major deal. 
