Martin Logan CLSIIz - adding more bass?

i'd suggest a pair of subs crossed over @ 60-70hz, w/a min of 24db/octave slope. i'd also suggest a pair of vmps larger subs. these are *awfully* hard to find used, but even brand-new, there's nothing that approaches 'em at anywhere near the price, even used. plus, their price includes direct shipping. most dealers will discount these at least 15%. pair these w/a decent x-over from db systems or marchand (or some hi-end used x-over), & a good used solid-state amp, & yule be happy. mebbe it'll be a bit more than $1500, but not by much, and at least yule be happy w/the results. i also buy mostly used, but the vmps were a no-brainer, & i've no desire to change (except to upgrade to their most recent drivers, but it's hard to imagine they could be faster/tighter than what i already have!)

What about the REL Stadium? Most CLS owners I've corresponded with claim this is the sub to have.

Thanks for everyone's responses...what about the crossover. Should I used an electronic one or a passive one?

ELECTRONIC IS THE WAY TO GO. However.....you really need to find one that is transparent enough to let the system benefits from bi-amping to show thru. Otherwise you end up hardening the overall sound. After a LONG search for an outboard electronic x-over for use with my Apogees, I can recommend the HSU outboard electronic x-over and at $459, it is a steal. I recommend the stock x-over point of 90 HZ, but you can set it lower with plig in chips. It has a 24 DB per octave slope for the high pass section (your CLSs) and 24 DB per octave for the low pass section or an all pass output which allows you to pass a copy of the input signal to the sub or elsewhere. You will immediately notice : more dynamics, greater output, greater transparency & ease and a larger, better defined soundstage. Not bad for a $500 tweak.

I have the same speakers and recently purchased used the kinegistic sw800, the same subs reviewed by aboslute sound with the m-ls and deemed the "super system", or something to that effect, still experimenting but they are seemless without the booming effect; my experimenting is somewhat more complex because i am using a meridian 568 processor through which i'm setting the controls; i believe there is a demo pair for sale on audiogon; steven