@eniac26
I think there may be a misunderstanding. If you are telling me you have a passive speaker, then there’s absolutely no way that swapping the speaker terminals would create or negate hum.
If I misread what I was responding to, I’m sorry.
If you have a passive speaker, and swapping the speaker terminals and it causes any hum to come or go, you have got a very very odd speaker with a metal connection to ground which should never have occurred.
This may not be true if your speaker itself has a connection to the wall AC, in that case all sorts of such interactions may occur if not properly paid attention to. This could be from an active speaker, an electrostat or the Focal's with the EM voice coils and outboard power supply. Now hum can become very rare, but not impossible.
Best,
Erik