Anybody have any insight as to why this might be happening? Everything else, high-hats, stick hits.. all sounds fine, but when a vocalist pronouces the sylable "S" it comes out "SSSSSSSSSSSSSSSSSSSS" ie: "CloSSSSing wallSSSSS and ticking ClockSSSSS" Almost a whistling. Suppose thats a fault of the speakers, amplification? What? thanks for the help. And i'm not driving the amp hard, its noticable at ~3 on the volume knob.