if you're yamaha RX-V1500 is like my RX-V2500 and has a 7-channel stereo mode, put it in 7-channel stereo (i can do this via the remote). then, go into manual setup and see if you can turn off your B&W fronts. i don't know if you can turn off the front mains in the manner, but i do know you can set the center to be off. if you can turn the mains off this way, then you can isolate your surround polks. just an idea. i've never tried turning my mains off in this manner.