Hi Mr. H,
The M22ti does a creditable job of bass to 40 Hz, but its bass output at higher levels will be limited without a sub. Even a cheapo sub will produce 40 Hz output or a bit lower, and your KLH has its own amp, so the M22ti will be relieved of deep bass duties (below 100 Hz), letting its woofers produce upper bass and midrange with ease and no sense of strain.
That's the point of using a sub with satellite speakers; even big full-range speakers benefit from a subwoofer with much-lowered distortion at the lowest frequencies.
Of course, a better sub (the Axiom EP125 or 175 or similar) will sound more musical and "tighter", which means it won't be boomy or bloated sounding.
But you can graduate to a better subwoofer as your budget permits.
Regards,
