Sound activated subwoofers?

[JamesPromIII]

Is there such a thing as a sound activated subwoofer, if so where can I find one that's got a red ring?

 

[LNCPapa]

It sounds like you may be talking about the old Cerwin Vega speaker surrounds, but I'm not sure what you mean by sound activated subwoofer.

 

[JamesPromIII]

Is there anyplace that would do that, or sell subwoofers like that?