I have a friend who has a "not to old" system. Recently he has noticed that when he changes the channel on his cable box (Comcast digital) the sub "pops". It does not THUMP! Also, whenever they are on a particualr channel, and the audio signal "goes" quiet (like a commercial) the "pop" also occurs.

I checked all the usauals and feel as though this may be in the preamp (Marantz AV560). His subwoofer is a Paradigm PW2200.

ANy thoughts or tests that I may be missing?

thanx

dgwing

Hi dgwing, a couple of thought.
Check the sub volume on the receiver, it may be too loud.

Could be static electricity build up.

Try adjusting the crossover setting.

Maybe a ground loop.
Just some ideas ...

is the sub set to "auto on" if it has that feature? some ive seen make a noise when turning on and off, and also can have a delayed turn on, so when you watch a quiet scene and then go to a loud scene or commercial it may "pop".

But aren't most auto-offs supposed to be more along the lines of "several minutes of silence", not several milliseconds?

I had something similar recently. Sub would issue a low "pop" on a periodic basis. It was the AV receiver that was bad in this case.

If you have an old demo unit you could swap the AVR's to see if the problem is in the recevier or the sub. Pretty much the only easy way to isolate the issue.

I had a similar problem with a Yahama reciever it would cause the sub to pop whenever it lost a digital audio signal. I sent it out and found out the surround processing board was bad, I just ended up replacing the unit with a new one.

Jason