I got this subwoofer for two reasons 1) My Wharfedale diamond 9.1 speakers sound great when I,m bypassing the tone controls on my hi-fi ( source direct ) but they do lack extended bass. I can always boost the bass via the amp, but when doing so I lost some of the gorgeous mids and highs. It isnt a problem with my equipment, its just that bookshelf style speakers arent physically able to deliver an extended sonic range purely because of the cone size and limited frequency range. 2) My Denon amp has a subwoofer out !! On receiving the sub, I was reassured first of all by the weight of it. I had looked up details about the SW150 on the net and know there is a lot of technology in the internal design to ensure optimum performance...this is not just a cone in a plastic case like so many other "subwoofers", there is an internal steel frame designed to prevent standing waves ( pushing the bass out to you and not letting it rumble inside the box ) The instructions were simple and it was connected to the amp 10 minutes after delivery. I inserted a CD and gradually turned up the volume of the sub. Yes--it does everything I wanted it to. I could hear the music warming up nicely and the bass is now fully extended and yet still tight and on the button. Its worth experimenting with placement as it does have a big effect on the level and quality of bass...I think they are called nodes or hotspots. A woofer doesn,t necessarily have to be in front of you to get the best performance and you cant really tell which direction low frequency sound waves are coming from-they are just there. I was lucky 1st time and it sounds great exactly where I hoped it would. Dont confuse this subwoofer with the nasty little rumblers that you get with TV surround systems, this is a genuine Hi Fi speaker and I bought it purely for listening to all types of music. As another reviewer said-forget about pseudo bass and dynamic bass boost that take away from every other frequency, get some deep natural bass to complement the sound. I did worry a bit about if the sub would upset the neighbours, I dont play "hammer beat" drum,n,bass or anything of that sort as I like music-not noise. Turns out they haven,t even noticed it and if anything I now play music at a lower volume because everything is "there" without having to boost volume or mess with tone. Last word to Superfi who delivered within 48hrs and with a tracked to the hour delivery.