While it doesn't take much skill to build a sub that will move a lot of air, it's a completely different story if you want it to be fast, tight, extended and well controlled with minimal ringing. To do this TYPICALLY means that the sub will be SPL limited unless size and number of drivers is of no concern. As many others will testify, the biggest problem with getting subs dialed in correctly has to do with crossover points, placement and matching the subs "speed" or "timbre" to that of the mains. Sometimes what gives optimum extension plays havoc with localization, imaging and timbre of the notes and vice-versa. Finding the right blend of all of these things is typically a compromise unless you have dual subs, a small fortune and a lot of time to dial them in. Keep in mind that some rooms will NEVER have good bass due to their dimensions, so pumping more and more funding into that situation might be a massive waste of time and money. My suggestion is to first OPTIMIZE your speaker placement and room acoustics and THEN think about a sub(s). Keep in mind that MOST "real" subs have a VERY limited operating range as to where they work most efficiently and trying to blend completely bass shy speakers with a sub will NOT make a great system. The subs would be forced to run up higher in their range than most are really designed to do and this results in compromised performance. "Subs" should be used strictly to extend what is already there, NOT to fill in what is non-existant. Producing "normal" amounts of bass would be the job of a woofer. If you don't have enough "reasonable" bottom end out of your mains, you simply need better speakers. NOT subs. The one exception that i know of to these generalizations would be "panel" type speakers with the use of a Rel or similar "sub". The Rel is designed to augment & "blend" with these and as such, is different than most of the other type subs on the market. In other words, do the basics first and then look at what would blend best with your specific room acoustics and speakers. Nobody has the same room or system to deal with so results can vary drastically. Sean > PS.... very small subs may produce a LOT of low frequency energy, but they typically lack TRUE "deep" bass and try to fool you / make up for it with a large peak at appr. 35 - 45 Hz. These types of subs lack "timbre" and attack while all the bass notes end up sounding the same. Great for movies and such but not for music.
