My subwoofer pops

[Unregistered]

It's a KEF PSW 2000 that has worked beautifully for almost two years. Suddenly, a couple of weeks ago, it lets out a large pop while a movie is playing at a fairly low volume. So far as I can tell, nothing about the setup had changed. And now, disconnected from the receiver, it'll still let out pops accasionally if I turn it on. I live in an old house with less than ideal wiring. The outlets are all only two-pronged, but I've used adapters and screwed the grounding attacchment into the plate.

 

[Rip Van Woofer]

If your wallplate and its attachment aren't grounded (you can't take that for granted) you haven't accomplished anything grounding-wise. But I don't think that's the problem. It's somewhere in the built-in amp; it needs service. If it's still under warranty do it before the warranty runs out!