[WalterBright]

> the needle picks up feedback from the room

But that's a bad thing. I learned to isolate the turntable from the speakers when playing disco. Also, had to walk softly else the needle would skip.

[mirimir]

Yes! Also, random noise can trigger asymptotic feedback at high levels. And asymptotic feedback tends to blow out amps and speakers.

[ectoplasm]

The best general purpose solution I've seen is suspending turntables on wide elastic bands. An isolated booth also works.