Martin Logan CLS setup

I use the clsIIz and my room is roughly 26 by 44 or something like that. It opens into a few open stairwells and another thousand feet of floor space or so. I have a TV instead of a fireplace, but this photo shows what I have done to make my speakers sound great.

http://steinman.mesls.org/stereo/DSCN8883.jpg

If you think this has some bearing on what you are getting at, I will measure it off for you.

Right now my electronics consist of a Tube research preamp and an Audio Matiere power amp (60w class A)

In that large of a room, you are probably going to need a larger amp. I use a Sanders ESL amplifier on my CLSIIA's and love it. I tried a Pass XA30.5, it sounded great, but just not enough juice. The XA100.5 monos were fantastic, but way too much money. The Sanders amp is a wonderful product at an excellent price. He has a 30 day trial period. You should really hear one with your CLSes.

Your CLSIIs will play with your 60 watt amp, but soon you will hear the short comings of not enough power. You may want to consider tube amplification. Any tube amplifier with 100 watts or more will do.

I assume you will be placing your speakers on either side of the fireplace. Pull the speakers 3' to 4' out with very little toe in. You will want to hang some window treatment on the windows behind the speakers. Don't worry about room treatment for now. See how the speakers react to your room.

If the speakers will not play loud enough there is a chance the panels are clogged and need replacement. When the panels get dirty from air born contaminants and humidity the efficiency of the speaker drops dramatically. Using the brush attachment with your vacuum cleaner and slowly moving it across the panels on a regular basis is a good practice. Replacement panels are expensive.

You will most likely want to try a subwoofer.

I've thinking of moving up in power at some point. The Audio Matiere is a tube amp and far out does its 60 watts however my plan to to go with a couple of 200 watt monoblocs from Tube Research. I'm not really having any trouble with volume levels but the bottom end could have a little more weight which I'm hope the extra power would help. The panels in these were replaced in 2001 and Martin logan told me the newer replacements are better, lighter and more responsive I don't know if that would be a significant step or not.