Does using a powered subwoofer make better sound?


I have Vienna Acoustic Mozarts. Wonderful speakers but their one weakness is below 40 Hz. I don't want to "harm" the beautiful mid-range and highs they produce. Would a powered sub give me the extra kick in bass I'd like? If so which one to buy?

System Theta Miles / Pro Prime IIIa DAC
Audio Research LS 15 Preamp
BAT VK-60 amp
128x128ghellen
REL has two lines of subs. The ST subs (Stratus, Storm, Stadium, Stentor, Studio) were designed with the Audiophile in mind. They also do a fine job for movies, if pure bass is your goal. The other line is the Q subs (Q100E, Q150E, Q201E, etc.) These are their HT line. They are also quite musical for the times you want tunes instead of movies.
Twl ... there are very few of my CDs which DON'T have information below 40Hz ... it may not be pure notes (e.g. organ pipes) it may simply be dynamics (e.g. kick drum, tympani). Furthermore I doubt that Ghellen can answer this question without first listening to some CDs with a good sub.

Ghellen ... try to demo a good sub. I really love the extra dimension that the sub (Rel strata in my case) adds to 80% of my CDs. It may or may not be to your taste, but the REL subs will almost certainly integrate seamlessly with your main speakers.
Titan II LE is one terrific sub for music. Comparable to the REL Stadium III but at far less cost (direct). Their new Force should also prove to be a winner. Do some searches here, at AA and AR and over at the SMR site. Also, see the reviews in Positive Feedback, BFS.