"Hey you" from The Wall has a great fretless bass under it. I mean it sounds really great. Is anything known about the specific bass used there? I realize that many of those earth-shattering notes are open strings so the fretless part doesn't really matter, but still. I read it is actually Tony Levin playing, who's a Music Man guy it seems, but that's probably some endorsement BS from after 1979. Bit difficult to navigate that space.