I've got an 8"Cambridge Soundworks subwoofer that bottoms out with low bass or dynamic peaks. It has to be turned down so low that its barely audible. It is basically useless as a subwoofer so I have got it working as a bass module above the HT 80 Hz crossover for my center channel. I would think this wouldn't be the case for your subwoofer but you might call the manufacturer for a solution. They may have encountered the problem before or they may replace your unit if you are still under warranty.
The vast majority of subs are going to do this, unless there is a subsonic filter somewhere., either in the recording chain, the receiver/preamp, one added by the consumer in the sub feed or in the sub itself. Really the filter needs to attenuate below the F3 if high power demands are going to be made of the sub.
Remember if the sub is ported you can't boost bass with Eq. I suspect a lot of these auto setups do this, and cause this trouble where it otherwise might not have surfaced. Although in a sealed sub Eq will extend the frequency response, remember it will get you into trouble with xmax for most of the subs in the price range talked about in these forums.
A sub with genuine high power extension to the 20 Hz range is going to cost a dollar or two.
I think that is why there has been significant interest in DIY subs. A sub is an excellent speaker starter project.
But one plea, please ask for our advice before you buy your components!
There are a few of us glad to it. It is a blessed relief from what "blaster would be better than this boomer for under $200!"
