[quote="Gasparius"]Unfortunately, this crackling is included in the mp3 song too.
I use the Mixcraft6 with WaveRT in Win7.
Write to the latency of less than 20 ms (3), but really do not know how much exactly.
Here I can not set the buffer size[/quote]
not sure if I'm understanding right but if you have the latency set right & still have pops/skips in both the recording & also the mp3 tacks perhaps you have clipping(too hot signal) somewhere. can you isolate each track & find it or is it in all tracks? I had the same issue w/ an intermittent snare drum track & realized I had clicked off the compressor for that track.