Having listened to music for most of my life, I have a pretty good understanding of how speakers sound (or fail to sound, or hurt my ears when they fail to sound, or...). All I know about subwoofers is what I feel about them, so to speak, and I know what they need to do. Subwoofers have "A" requirements that often conflict: Accuracy: When listening to the Grateful Dead jam, I want to hear the individual notes Phil Lesh plays on the bass, and I want to hear the low percussive beats. Accuracy comes down to precisely the sub moves moderate volumes of air. Amplitude: I don't care which notes special effects hit. I want to feel the impact of the effects rumble through the room and my chest. In rock 'n roll terms, "Shake it baby, shake it!" Amplitude comes down to how quickly the sub can move large volumes of air. Unlike music, however, HT must sustain those movements of air. I totally get lost understanding how various manufacturers achieve those results. (Why do some 8" woofers outperform 18" woofers?) More importantly, I do not know what to look for in specs and reviews that indicate how well they perform the various functions. Within any given manufacturer I do not know which product lines (and which models within the lines) match up to various speaker lines. Yeah, I know woofers don't match like fronts and centers, but I assume general capabilities will correspond. Being a cheap basid, I'm looking to maximize bang for the buck by purchasing used or "vintage" product that matches my needs. Can some one point me to a few links that explain: the basics of how subwoofers work the different approaches taken to achieve results the trade-offs involved in various subwoofer designs how to read and understand the specs how to match subwoofer specs/reviews to speaker reviews I may have graduated 20 years ago, but I still cannot get away from the mindset that needs to understand "how" and "why" so I can apply governing principles to my own situation.