I have a brand new Paradigm 10" subwoofer. It doesn't have an on/off switch but it powers down after a few minutes when no signal is present. I noticed that when it's "off" it still generates a very slight hum/buzz -- is this normal? Or should it be completely silent when not being used? (If I unplug the sub the hum/buzz goes away.)

Is the hum/buzz coming from the driver, or from the amp? There is a transformer in the amp which would always have power, so it's possible it is creating some hum. But if the driver is creating the hum, and the power lights are indicating that the amp is powered down, that doesn't seem right. Or are you just assuming it's powering off after a few minutes? You could have a ground loop or other noise in you line level connection that is preventing the sub from powering down. You can test that by unplugging the line level connection but leaving the sub plugged in.

But if the driver is creating the hum, and the power lights are indicating that the amp is powered down, that doesn't seem right. -- Darin

Again, the hum is only noticeable when the room is extremely still and quiet. As soon as I unplug the sub, the hum completely disappears so I doubt that it's the amp.

Again, the hum is only noticeable when the room is extremely still and quiet. As soon as I unplug the sub, the hum completely disappears so I doubt that it's the amp.

I'm talking about the amp in the sub. If there's a slight hum coming from the amp in the sub, then it could just be the transformer. They shouldn't produce audible noise, but they can. But if the sound is coming from the driver (which you should be able to test by feeling it... you should be able to feel it vibrating slightly), then your (sub) amp isn't really powering down.

I'm talking about the amp in the sub. If there's a slight hum coming from the amp in the sub, then it could just be the transformer. They shouldn't produce audible noise, but they can. But if the sound is coming from the driver (which you should be able to test by feeling it... you should be able to feel it vibrating slightly), then your (sub) amp isn't really powering down.

Understood, Darin, you obviously know more about the internals than I do ;)

I'll try your suggestions. Much appreciated.