Used monitor under$600 with good bass low levels

Triangle Titus (very small with clean if not deep bass) or larger Triangle Comete or
Ohm L (bookshelf) with Ohm sub-bass activator tweak.

Whoops, sorry Triangle Titus cannot be biamped and Ohm L is 3 not 2 way.

Both are good, smaller box designs for well under $600 used though.

PEdrillo,

If you think there is even a chance you might keep them, you should do the in-house audition of the Ohms...there is no risk involved if they do not work out.

If your listening space is tight you might be satisfied with a pair of small Micro Walsh Talls for ~$1000 or so, particularly with the existing sub. I think the Atmasphere amp could work really well with these smaller Ohms. I can also vouch that the Denon 103R even on my comparably modest table sounds outstanding on my Ohms!

Tobias,

You're right, Triangle Titus can be biwired. I had forgotten. Same with Titus 202s I own. Probably also the case with Comete.