With COVID-19 starting to cause significant lockdowns, our music lessons have moved to online. Our piano and cello teachers are both using Zoom for this.
Piano was fine, but the Cello teacher noticed that when my eldest son was playing some notes (especially the lower ones), the audio was cutting out. When he mentioned it was fine at the start of the note, but dropped in the middle, and then came back at the end, it triggered something in my brain.
Turns out Zoom has automatic background noise cancellation. This was picking up the low sounds of the Cello and blocking them.
This is fairly easy to fix:
Settings → Audio → Advanced
Then, set both types of background noise suppression to disabled:
I’m not sure which one is more important: you’d think it was probably intermittent, but it was easy enough in our case just to leave them both set to disable.