Studio monitor switch

Hi All.
a friend of mine has a recording studio. He Wants to run two sets of monitor speakers from his mixing condole’s Left and Right outputs. They are active speakers.
Lets call them speakers A and B.
He wants a switch than can switch between speakers A and B.
The system need to stay balanced using XLR’s.
The other issue is that when one set of speakers are receiving signal, the other set’s inputs will have to be grounded T prevent them from picking up hum (50Hz) where I live.
I need some ideas on how to fo this. Obviously there are many ways to skin a cat.
Thanks.

Double pole double throw switch - easy as that.

As the active inputs are fairly insensitive, relatively low impedance, and balanced 0 there probably shouldn't be any hum pickup issues.

Easy to check - simply unplug the XLR from the back of the mixer and see if it hums.

Nigel Goodwin said:

Easy to check - simply unplug the XLR from the back of the mixer and see if it hums.

Click to expand...

If they do pick up any hum, you should be able to eliminate with eg. a 1k5 or 2k2 resistors permanently connected from each signal pin on the switch box output sockets, to the socket ground pin.

That should prevent anything "floating" but have little or no effect on the wanted audio.

It may also reduce any clicks or thumps when the switch is changed over.