1. The crackling noise is due to insufficient CPU usage.
2. CPU will overload more easily on certain presets with more effects and/or dual amp setting.
3. Lower Buffer Size and/or higher Sample Rate setting will also cause higher CPU load.
4. Having other applications running will eat up the CPU usage as well, resulting higher CPU usage.
So when encountering the crackling noise, we recommend you look into the following:
1. Go to Audio Setting (of BIAS FX 2 or your DAW), set the Sample Rate to 48k or lower, set the Buffer Size to 256 or higher.
2. Avoid opening other applications at the same time, and turn off unnecessary applications running in the background.
3. For Windows users, we recommend you follow any of the guides below to optimize the system for better CPU performance for audio production work.
https://support.focusrite.com/hc/en-gb/articles/207355205-Optimising-your-PC-for-Audio-on-Windows-10
https://www.sweetwater.com/sweetcare/articles/pc-optimization-guide-for-windows-10/
4. Avoid using multiple instances of BIAS FX 2 plugins as it multiplies the CPU usage and can lead to CPU limit quite easily. A common practice would be export the tracks with BIAS FX 2 to WAV files and reimport them into the session. This way you have the audio files without having to run multiple plugins in order to save CPU usage.
*For Windows users having the crackling/popping noise issue in BIAS FX/Amp/Pedal standalone,
(1) Please make sure you've tried both 32bit & 64bit versions.
(2) Please check if the audio driver for your audio interface is up to date
(3) Please try another driver like ASIO4ALL