I have 8 Yamaha 6ohm speakers at my house for out door music use. They sound great when properly powered. I haven't been able to find an amp or receiver that would run all 8 and make them sound good. Would you please recommend a receiver or amplifier to run these on. I'd also like a recommendation on a good switch to use so I can either run all at once or any combination of the 4 pair. Thanks for any help.