I’m not sure how this has happened as I’ve had previous success using all the same kit to record (Behringer UMC202HD, electric guitar w/ pedalboard, Audacity) but:
When I now go to record the audio is really crackly and cuts in and out. I’m not sure why this is happening as the headphones straight from the interface are giving v good sound quality with no issues, but the moment I listen back on Audacity there is a crackle and the quality is very poor.
Could someone please help me with why this is happening and how I can fix it?
Sounds typical of dropouts due to inadequate buffer size. Increase the size, until the dropouts cease and the sound is smooth. Be aware that increasing the buffer size adds latency (which matters mainly when recording with a microphone). Your CPU may not be meeting the power demand because some unnecessary app is running in the background. Ctrl+Al+Del → Processes tab → scroll down and see what might be using up resources (which can be corrected in msconfig). If using an audio interface, play with its buffer size. The buffer can be temporarily increased.