I have an old pair of Radio Shack Optimus speakers I used to use as surround speakers. They are rated at 40 watts MAX at 8 ohms. I just got a Yamaha RX-V1400 which I'm currently running with 5.1 setup. Could the old Radio Shack speakers (40 Watts) be used as Surround Backs even though the 1400 can put out 110 watts per channel?