First, unplug the subwoofer and try the switching again, to see if it is _only_ the subwoofer causing the noise. If the noise is still there, through the other speakers, it could be either your DVD player or the 950 causing the problem. If the noise _only_ happens in the subwoofer, there might be some problem with the 'standby' power circuit itnside it. Some subs power themselves down to 'sleep' mode in the absense of signal. When a signal is detected, they turn themselves back on, which should _not_ cause a big thump. If there is a switch on the sub to make it stay on continously, do that, and see if it still thumps when you switch the DVD and TV.

If the sub is not the problem, try switching from your DVD to some other input that is in 'analog' mode, even with nothing attached to that input. It the thump goes away, it is possibly the TV. Reverse the procedure, switching from the TV to a digital input with nothing connected to see if the DVD player might be causing the problem.

I would tend to thing the problem lies in the auto power switching in your sub woofer. One other thing, are your DVD and TVs power "on" _before_ you do the switching from DVD to TV? They should be. If you do isolate the cause, and it seems to be a defect, there is unfortunately nothing you can do yourself to repair the 950, your DVD or TV. That should be left to the manufacturer.

One final thought. Make sure that all your interconnects are in good shape, and not corroded: gold plated ones are the best in this regard, but you don't have to spend a lot of money to get ones that will work well. Good luck!