My cretaceous period license for Sound Soap had a hum filter. It automatically selected all the cardinal frequencies (60, 120, 180, etc in the US) and you could put it on as needed completely independently of the show, sampling frequencies or profiles) I assume they were extremely sharp notches unlikely to damage the sound unless you were particularly unlucky.
“Rapunzel hit that high note about 2/3 of the way through the adagio and her voice vanished. It was most extraordinary…”
Koz