Okay, so I had decided to build a sub-woofer for a speech topic for school, and I was wondering what it was that made speakers, or sub-woofers so loud an efficient. Granted, I know mine is far from great, while being made from ply-wood, duct-tape, and everything, but why is it that professionally manufactured speakers are so loud by them-selves with minimal power? I am using the circuits from my Logitech X-240 system, and the sub-woofer is always way louder than that of my home-made speaekr, with a significantly smaller ceramic magnet, it seems. Is it the geometry of the speaker itself, or what? What do manufacturers do in construction which improves the sound, or quality of speakers, and would using a neodymium magnet be better than using ceramic magnets? Any help is appreciated, and thank you in advance.