I just thought of something .Two things ,kinda stupid but might work .Laugh if you want but a "tinfoil hat " for the speakers .
Take two layers of foil and seperate them by about two inchs and surround the speakers ,ground the inside layer . If the seperation is correct as well the thickness it in theory would bounce the signal back and forth until it attenuated .
Second ,find a piece of old fashion 300 ohm twin lead antenia wire ,about ten feet .Somehow connect it to the speaker,both leads just one end of it .Take about 6 inchs of aluminum foil and wrap around the wire ,have it connect to ground .This set up is a capacitor,low level .In theory by sliding the foil up and down the wire it effectively is a bad reject filter and would shunt the signal to ground . Both may or may not work .
The tv lead in wire thing was used in the early days of cable tv when the cable companys put a carrier on the signal to prevent people from getting free cable service . With elecronics transmissions of data ,there has always been an "underground ",still is ,look at the internet .
