We've been juicing a vintage Logitech 5.1 Z5500 on our screened porch for years in sync with our primary receiver.

Edit. PSA. If you don't use a land line and just use cell's now it's easy to use your homes existing phone jacks to transfer a discrete stereo source from the zone 2 capability from your primary receiver to any other room with a phone jack. Not just for a separate stereo or 5:1 system but for a pair of self powered speakers too.