There are many different home audio or powered theater subwoofers offered on the market today, the major problem with them is flexibility. I propose building your own subwoofer to suit your tastes. Any reasonable quality surround sound receiver ot procesor will have asubwoofer output built in in the back in order for the consumer to be able to simply plug in a powered sub and play, some having two outputs, left and right that are crossed over for this purpose. By assembling your own components you can create a much more effective base operation taylored to suit you needs. If all you desire is a moderate increase in base at lower vollumes an inexpensive powered subwoofer is all that is needed, however if you are attempting to get theatre levels of performance from demanding recordings creating your own subwoofer ste up is desireable. First of low base note consume up to 70% of your amplifiers power, in order to free up all of that power you will need an amplifier,this does not have to be the cleanest power but you will need lots of it. If your system is 100 watts per channel I would recomend 400 watts mono for a subwoofer. Pro audio or band equipoment is perfect for this as they offer gobs of power that will deliver that power into dificult loads and usualy have onboard fans for cooling. You can puchase a Peavey amplifier that is 800 watts into mono for less than $300.00 including shipping on ebay. Thje next step is to decide what type of base you like, super low window rumbling make youi pant legs flutter or super fast smmoth well defind basr notes.For the pant leg flapping I would once again recomend a pro audio. or band subwoofer 15 to 18 inches in a folded horn cabinet from the likes of JBL or ELECTEOVOICE. If more accurate base is prefered a single 10 or 12 inch woofer is best, such as VELODYNE or KLIPSCH. Once you have the raw drivers you can either build a cabinet using information found on the internet, such as sealed or poted cabinet and internal cabinet size recomendations or you can usualy find old speaker cabinets at thrift stores with this size openings and install your woofers into them. The conection to your system assuiming you have a subwoofer output is simple, run the wires from the woofer out a small hole in the back of the cabinet and connect to the speaker otputs on thje amplifier, and then plug tha amplifier into the subwoofer output to your system. You wiil want to purchase an amplifier with output level control so that you can taylor the levels to you desires. At this point you are free to enjoy as is por experiment with different woofer by reselling yours on ebay and auditioning others whenever you like. Having an 800 watt amplifier will assure that you will be able to drive even the most power hungry woofers to sound pressure levels past what you need effortlessly keeping the woofer under control at all time all the while keeping any sort of distortion minimised.