Audio Systems: Pooping Sound, radical difference, changing channels

Question
I have a Kenwood VR-6070 hooked up to to my surround sound system.
Every time I change the channel for video or tv my M&K sub woofer makes a pooping sound. I
thought it might be the sub so I tried my other one and it still makes
a pooping sound. What could be the problem?   Thanks

Answer
It's not uncommon for something like this when changing channels / inputs. It's more than likely caused by the radical difference in the audio signal being sent to the subwoofer between channels.
As far as how to stop it? I'm not sure if you can. Some systems are more problematic than others.