Just listening through three sets I taped on Monday night and all seem to have an intermittent (but quite frequent) rumble-type noise. Each episode lasts less than 1sec and looking at the frequency analysis it's mainly 40-80Hz. The sound is almost like the noise you get when you gently blow across a capsule.
Recorded with the same setup in the same room one week before with no issue whatsoever. Just wondering if this might be noise caused by the mic cables moving around during recording.
Rolling off the frequencies below 80Hz seems to make it less noticeable without affecting the music too much.
Any thoughts? I'll try and get a sample posted too.