I just purchased a Philips DVD Home Theater System HTS3544/37, I've only had it for one day and the subwoofer is rattling. I ran a test on it playing a sound that runs from 100hz down to 15hz and the closer it got to 15hz the more it rattled. I know if it is the sub that is rattling and not something in the wall or around the sub. It is s a passive 8" high efficiency 8 ohnm sub. Any suggestions on what might be the problem and how I might go about fixing it? I tried to post a link to the HT System via the Philips website but this is my first post. If you google the model you should be able to find it.