[Floris Liesker]

This is an old thread but nevertheless the problem persists in Premiere Pro CC. I also found a plausable cause.
The audio will crackle randomly if the sample rate of the .pek file and the sample rate of the timeline differ.
Halfway through a project I noticed the timeline was set to 44.1 kHz instead of 48 kHz
When I changed it to 48 kHz the random crackling started. Mostly at the start of a clip, must be due to inferior realtime conversion algorithm.
Premiere will try to playback the 44.1 preview (.pek) files while outputting at 48 kHz.
Deleting the .pek files forces premiere to recreate them in the right sample rate and all is fine…