Intermittent crackling

Hi,

When either recording without live monitoring, recording with live monitoring, or live monitoring without recording, everything will be good for 2-20 minutes after starting the monitoring and/or recording. After that variable amount of time I start hearing crackling in addition to the recorded material. If I switch between recording and monitoring (e.g. while live monitoring the audio source, click the record button to start recording while the external source continues singing/playing/etc.), the crackling immediately stops for 2-20 minutes, then starts again. I followed a lot of the good advice on the forum and in the manual, but I am still experiencing this issue. For example:

  • Set the sound card recording bits/sampling frequency and Audacity bits/sampling frequency to the same values (24 bit, 44100Hz)
  • Audacity project rate = 44100Hz
  • Both “exclusive mode” boxes are checked for the sound card recording
  • Use Windows DirectSound (we have also tried MME)
  • Use a high end sound card
  • Disable the Realtek embedded sound devices

The fact that the crackling stops when switching between live monitoring and recording tells me that the issue is not related to microphone, analog preamp, cabling, connectors, etc. It crackles during quiet and loud passages, so it isn’t overdrive. Crackling is heard on the recording itself and always in the same place.

Any other suggestions?

Thanks,
Daniel

Windows 7 64 bit
Xeon processor with 4 cores, 2.8 MHz clock
8 Gb RAM
Digital Audio Labs CardDeluxe sound card
Audacity 2.0.2