Hi, I got this Woofer,Name TBT, which damaged its Radio module, then was added a Bluetooth module from the market(history from client). Then recently was brought to me with very low sound and heating problem. I changed subwoofer Speaker which had impedance of 1.2 instead of 4ohms rms and the bass ic KA2206B. Sound is back but buzzing and hissing sound present even when muted. How can I get rid of it?