Help with buzzing, don't know what else to try

[kozikowski]

I wonder if we're listening to the same thing. I captured "That is the maximum quiet, more or less" clip and it has very little buzz and hum. I got very quiet noise floor by filtering out everything below 20Hz. Low pitch beyond audibility—doesn't affect music. The clip after that, "Do you dream..." yes, that has a very annoying hum in it.

How did you produce that first clip, and can you do it again?

Koz