Discovered Bob Wiseman via Tomboyfriend site (don't know how - but I did).
Listen to this experiment. He sets up what I believe is a straight E harmonic and then plays the bass part around it, carefully avoiding hitting the E note. No wait that's a low, low A, I think. I can sing with it but it's as low as I can go. Then the babbling brook changes the harmonic to a higher A. I think he's playing with-in a schematic diagram as he moves to higher and higher tones. Then he plays with percussion type stuff with that thing; yeah the piano thing, thing - and the stool too.
Bob Wiseman's Youtube Channel.