I need advice for getting a new sub. The room size is about 15ft x 20ft x 8ft. I will be using the sub with my KEF Q15 bookshelf speakers. This will be the first time for me to buy a subwoofer. I am really not looking for the greatest bang for the buck. I know many subwoofers for movies emphasize on the 40-100Hz range. I rather have a subwoofer that is less boomy but can perform at frequency near 20Hz. But this is a subjective matter. While driving I am sure many experienced the ground shaking bass coming from someone elses car. I do not understand these people who enjoy such overwhelming bass, but my point is that there are many people out there who are different from me and rather have a boomy subwoofer. Therefore by just reading online it is hard to determine whether a particular subwoofer is for me. Although I will be using the subwoofer for both music and movies, it is more important to me that it performs well with music. Since I only have bookshelf speakers I really need a subwoofer to extend the bottom frequency range. I like for music to sound like the musicians are playing the instruments right in front of me. I am afraid the wrong sub would make things worst. However, there is always the problem with the budget. So a particular subwoofer that interests me, and also in my budget range, is the Mordaunt-Short 909w. I havent found a place to listen to it yet. But I just want to know if this sub would work for me. I read the reviews, but they are written from a home-cinema perspective, so I didnt know if it is one of those sub that provides too much energy in the 40Hz- 100Hz range but not enough below that. If this is not a good choice, please recommend another in similar price range. Any advice and help would be greatly appreciated. Thanks.