I second the REL suggestion and found that setting up my Q150e (10" 150
watt bought used for 200 bucks) in a medium sized room was easy. Move the
REL around until it sounds good, don't turn it up too much, and adjust the
crossover level to blend with the lower range of your mains. I'm not a fan of
"Room Mode" correction gizmos as they add extra wiring detours on
the music signal, impose some geek designer's opinion of what's
"correct" and can be a waste of money if you own furniture. A REL's
"high level" input utilizes the sound of your amp without bothering
the mains speakers (or the amp). Most REL users find that the ambient presence
of these (or any good sub) somehow "pressurizes" the room making
even bass shy recordings feel better. If setting up a REL provides "difficult
alchemy" you need to get out more.
