There are A speakers, B speakers & 2nd room preamp outs on your receiver.

-A speakers would be the mains: L & R, C, LS, RS

-B speakers would be for an additional set of speakers (for another room/area) L & R (stereo) and would have to listen to the same source as A speakers. Volume would raise & lower for BOTH A & B at the same time.

-2nd Room output (RCA) is non-amplified and would require and additional amplifier to power speakers. This can have a different source playing than main room (A & B speakers).

I use the 2nd room output on my Sony receiver the following way:

2nd room output (RCA preamp) ---> Onkyo 8211 stereo receiver (Tape input)

Onkyo 8211 stereo receiver speaker A outputs (L & R) ---> Niles Impedance matching speaker selector switch

Impedance matching speaker selector switch ---> 8 pair of speakers throughout my home (Kitchen, Dining Room, Master Bedroom, Master Bath, Guest Bath, Front Porch, Rear Patio, Garage). I can choose any individual set of speakers or all.

Hope this helps to understand the flow/connections.

Sonicflood