I've heard this and attributed it to room noise picked up by the mic used to record the piano.

Its more evident when the piano is solo or nearly so.

Yeah, you're not hearing things..... it's there.


You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.