Hi I recently brought a new pair of Infinity Alpha front speakers and Infinity Primus Center speakers. I have a marantz sr4200 receiver and noticed that this is this hiss..hissing sound coming out only from the tweeter of the front speakers. It turn louder as the volume go up. But when I press mute while playing CD/DVD/Tuner, no hiss at all. That's quite different from the usual case that I know from other threads. I have tried unplug all inputs to my receiver and power up just that and it still hiss. I also tried re-do the interconnect but no luck. The infinity center is dead quite (even at high vol) but not the front. If the culprit is sr4200, why doesn't the center hiss? It is very annoying, I can heard the sound about 1 meter away when the volume turn up to 0 to -5 db. Could anyone tell me how to solve this?