What do you guys think about my little theory?

I guess you'd be able to get chatter if you put a dump valve on and put a bleed valve into the vacuum hose that's controlling the d/v. Bleed away most of the air so that the piston in the dump valve is only opening a tiny little bit when on vacuum and therefore allowing the "sound" to escape, yet maintaining enough pressure inside the hoses to stall the compressor wheel.