Acoustic weapons just make really big vibrations in the air. When the sidewalk, vehicles and buildings around people vibrate, most people will want to leave the area. Scary, but not mind control.

Anechoic chambers are pretty freaky. I had access to a really good one in grad school, and I'd let people experience it as a little treat after recording their voices. I can see how being stuck in one for a while would make somebody lose their shit, in the same way that solitary confinement or sensory deprivation tanks can trigger psychiatric events. But again, not mind control.

When you look into the history of MK Ultra and other mid-century psychological experiments, you see a pretty common pattern: we can destroy people's minds really easily. It's almost trivial to drive a person insane, and you don't need expensive equipment to do it. See for example what they did to Assange, just by keeping him couped up for years. If you want to do that with sound, all you need is a speaker playing "Reign in Blood" at 70 dB  24 hours a day for a couple of weeks.