If you want everyone to hear you, you might try something like my setup. I have an old stereo amp (like, real old), hooked up to two old stereo towers (10 inch woofer, two 5 1/4 inch midranges, and a 2 1/2 inch tweeter each), and a set of sennheiser headphones. When I play counterstrike, I have the output split between the headphones and the amp, and I turn the headphones up as loud as I want. I then turn the bass all the way up on the amp, the treble all the way down, add the high filter, and crank the volume. I get all the surround sound through the headphones, but when a grenade goes off, or there's a ton of gunfire, the stereo amp really kicks out the bass and shakes the entire room, and a few of the rooms around me. Because the towers are outputting almost all bass (which is omnidirectional), they don't screw up the surround sound from the headphones, so I can still hear exactly where someone is by their footsteps.
Summary: If you want loud, don't mess with computer speakers, and get yourself an amp and some real speakers.
Lyrics. Wasted time between solos.