I know of two that 100% have the crackling sound. The first time I heard it I was listening to Chloroform. It actually broke the trance I was getting into because I thought something was wrong w/ my headphones and/or computer. This was in the .drg file. I also tried the .mp3 and it was there too, so I relaxed about it.
Last night, I was listening to Datura (using it as a trance helper w/ a self-hypnosis file I was running w/ it), and it happened about 2/3's of the way through. This time I wasn't surprised or worried about it, but unfortunately the volume (despite it being on minimum volume) of it drowned out the voice of the hypnosis mp3 I was running. It ruined the trance basically.
I usually use Theta & Delta binaurals (not always I Doser ones) to help w/ hypnosis tracks, but recently I've been wandering and using over doses to see what kind of effects they would have. Datura description says it is the best to get that amazing 'trance' effect. Low & behold, it had the static/crackling in it.