I second Pdreher's recommendation of a REL Storm III sub. The single biggest improvement to my system was adding an active sub, especially the REL, which gets its signal from the amps, not the pre-amp, and a seamless blend with your speakers is easier to achieve.
Borrow one, demo one, or buy one on Audiogon (and sell it without a loss if it doesn't do it for you). It really fleshes out the sound of your system, and not just on bass-heavy material. Even acapella vocals benefit -- with the sub, you hear more of the 'room' the music was recorded in. A good, musical sub adds so much more than just lower octave information!
I know the exact difference in sound you're describing when you describe your friend's system vs. yours -- yours sounds anemic and as if certain frequency ranges sound good at the expense of others; his sounds full and well-balanced.
My advice: before replacing any of your components or speakers, try supplementing what you have with a REL sub, and see how you like the difference.
Good luck!
Borrow one, demo one, or buy one on Audiogon (and sell it without a loss if it doesn't do it for you). It really fleshes out the sound of your system, and not just on bass-heavy material. Even acapella vocals benefit -- with the sub, you hear more of the 'room' the music was recorded in. A good, musical sub adds so much more than just lower octave information!
I know the exact difference in sound you're describing when you describe your friend's system vs. yours -- yours sounds anemic and as if certain frequency ranges sound good at the expense of others; his sounds full and well-balanced.
My advice: before replacing any of your components or speakers, try supplementing what you have with a REL sub, and see how you like the difference.
Good luck!