Hi Stephen
I’m having the same problem. In my case the crackling audio in the export output occurs when I’m exporting from a nested sequence. If I export the same clips from a “basic”, un-nested sequence, the audio is OK.
Have you noticed the same in your case?
Furthermore the crackling audio only occurs in clips where I have applied some audio effects (MultibandCompressor).
Have you noticed the same in your case?
/Hugin