Puff Goes the Sunfire Mk II Subwoofer

Every now and then (and I have not yet discerned a pattern), my sunfire MK II subwoofer makes a soft but very noticeable puff sound. The sound is similar to the thump that you would hear unplugging a heavily amped subwoofer from the wall, but not as loud. My first thought was that I must have a bum cable, but I swapped out the cable and still have the problem. I am running a Sunfire Theater Grand II pre/pro. I also have a nasty ground loop problem which I solved (without any problems until now) with an Entech humbuster box in line between the pre and the sub. The ground effect is coming in from a dirty RF signal from my cable TV provider. I am also using two star-clustered Richard Gray Power Company 400s units which I have all of my stuff plugged into (pre/pro, Sunfire Cinema Grand amp, sub, Kenwood 5900M CD/DVD, Scientific Atlanta Explorer 2100 cable box, Sharpvision 34N-WF5H TV). The problem started when I added the Richard Grays but I don't see how the problem would be related; it seems like a coincidence. Hu-Hu-Hu Help!
Are all of your powered components plugged into the same circuit / outlet ?

Did you try any of the steps outlined in a post about AC polarity / hum / noise that was posted a few weeks back ?

As to being a coincidence with the Richard Gray pieces, try pulling them out and see if the problem goes away. If it does, get rid of them. When an electronic product makes unexpected or unexplainable noises, it is a "cry for help". It might be a minor problem, it might not. The only way to tell would be to either take steps to correct it or wait it out and see... Sean
I had a Sunfire Signature sub with the (same?) problem. It was in my living room video system. The sub was very sensitive to any power surges in the room. I eventually ran the sub only on a heavy extension cord to another circuit in another room. I recently sold the sub to a friend who has it in his video on a dedicated circuit - no problems at all. I found the lower you have the level control set on the sub, the sooner it will go to stand by on the "auto on" mode. Then it will stay off until a bass demand triggers it, then the muted "thump".

i agree...try removing the RGPC one at a time to see if you can isolate the potential problem. Please keep us posted on results, as I am curious about RGPC stuff.

Thanks and good luck!!!

I found that Sunfire offered excellent customer service. I had a case of a strange noise & they determined that an internal coupling had come loose. They were very helpful and may have heard of your problem before.
Try running two or three dedicated lines to your system. They really do work wonders. In fact that's my favorite tweak :~)
Try setting your processor bass level as low as possible, & the level control on the sub as high as possible. This will minimize the sub's tendency to go into standby mode during a quiet movie passage or musical segment. It worked for me..

this may sound weird but my cheapo HT all in one Onkyo subwoofer does the same thing and it drove me nuts. After follwoing its pattern, I saw it did that when a car drove by and when my garage door opened. Cell phone and radio signals was the culprit and made the woofer pop or thump. I tried to get my city to ban cell phones in my neighborhood but they declined so now I just unplug the thing when im not using it.
Derrick, i can see it now. Your standing at the podium testifying against a whole CITY full of cell phone users trying to explain how they are bad for your high fidelity gear. Only on "Court TV" : )

Out of curiousity, have you guys tried changing power cords and interconnects ? If the power cords are attached, what about adding ferrite chokes as close to the amp as possible ? You might also want to try this if you have a "sense" wire that remotely turns the sub on from your pre or processor. Since that wire is probably pretty scrawny, you might want to try making several loops through the ferrite to improve the efficiency.

Just a thought and hope it helps... Sean