Since I do not know your room I will take blind stab here.
Well, maybe a PS Audio Power Plant will do. No, no first, more than likely your speaker positioning and your room acoustics will need to be dealt with. The wall behind your speakers probably needs some treatment. And are your speakers pulled way out from the side wall and especially the rear wall, like 3 feet? And avoid the toe in temptation.
I have a bright room. Live walls everywhere. I took 3 inch Sonex and cut 12 inch squares and did a checkerboard on my back wall. I also used the same for my mirror points on the side walls and the roof and I threw down a thick rug on the wood on cement floor. ( My wife is very cool! ). These tweaks did many good things and became essential instead of options.
Your system is very good. The Adcom CD does not carry the shrill moniker like the amps do. So I will advise to deal with your room and look into a power treatment like the PS Audio or Equi-Tech. Dale
1st check out if your power amplifier can be used with passive preamp.
Power amp shoud have high gain and high sencitivity.
CD player have to swing with ~3V output voltage for ideal case and input sencitivity of your amp shoud be ~0.6V
Also check input impedance of your power amp. It has to be at least 47kOhm.
I've found that in making choices for my system, the sound tended toward being too bright unless I deliberatly chose components or cabling for their warmth. For example, I'm using Stealth CWS interconnects (similar to yours and pretty much neutral, which means they do nothing to attenuate bright, harsh sound), but I'm also using Stealth PC speaker cables, which are warmer-sounding than many silver speaker cables. I'd guess too that for those of us who like the dynamics of active preamps, your evs passive (splendid and accurate as it is) might sound bright. Before I spent big $, I'd probably try an inexpensive preamp--maybe just use the preamp section of an old receiver. I'd also try using some cheap cables, which probably would have a weak high-frequency response, just to get an idea how much the cabling contributes to the problem. Best wishes.
I will take a stab as well. First and foremost, I would suggest you audition some other Interconnects and Speaker Wire. Silver is great when used in the right system. In most cases it will add brightness and a general hardness to most pure solid state systems. I also agree with MCNE and suggest you try some room treatments.
I use a large decorative rug which I have mounted on my main wall in my listening room behind my speakers. This not only improved imaging but also removed any glare from in the treble I had ever witnessed. My 2 cents for what it is worth. Good Luck and Good Listening!
I would check with Ric Schultz at EVS for any recommendations he may have. I have experienced much of what you are experiencing but am not sure the fixes I have found would prove effective in your system. I am using speakers with metal cone drivers and suspect that they contribute to the brightness I have mostly tamed. Ric endorses cables manufactured by Zcable. I am using Zcable "Thunder" power cords and could not be more pleased. I also am using the Zcable "Live" interconnect. I can now listen for hours on end without fatigue. Another product that has helped are Acme Audio Power outlets. Feel free to contact me if you think I can be of any assistance.
I had an awefully bright system with Thiel 1.5s. Two things did the trick and a third is on it's way. 1) Like Mcne said, try repositioning your speakers and avoid toe-in. 2) Try MIT MH-750 speaker wire and MI-330 interconnects. The newer MIT interconnects are impedance matched to your amp. Your's wasn't on the list but I'm sure contacting MIT will get you the right match. Thiels seem to really like networked cables. 3) I'm getting a set of Sound Anchors stands. You don't want the aluminum tweeter pointing right at your ears. With the 1.5s the stands will lift the tweeter about a foot over my head in the listening position. I anticipate this do work beautifully. Granted the 3.6s are a good deal taller than the 1.5s but it maybe the case.
I don't want to sound like I'm knocking the Thiels. They'll just bring out the worst in a system that doesn't "gel" with them. The MIT cabling and repositioning already has the brightness 90% tamed for me. The Thiels are also very position sensitive. Even a half inch change can bring noticably different sound.
Hope this helps. leo.
Gotta start with the Thiels in the room.
First order crossovers can require careful placement, and most Thiels sound a bit uptilted in any but the deadest rooms. Blah, blah, blah...we all know this.
Here's a smaller bit of it, though:
I was REALLY surprised at how floating my previous old CDP (Rotel 855) on a Neuance iso-shelf, although NOT changing the sound spectrally, but by improving the coherence of the frequency range resulted in a more unified, musical integrity that allowed me to accept some brightness because
`of improved resolution. Pretty interesting. I'd try popping your Adcom on a Neuance before replacing it or smothering it with a too-warm cable. You don't want to suck the air out of it.
Does your room have wall-tp-wall carpeting? Are you absorbing first reflections off the sidewalls? The point is to tame the 2-6kHz stuff without rolling off the 10-20kHz air.
Are you using any nice power cables?
I am using a chang power cord for the amp and an audioquest ac-15 for the cd player. I also use a chang lightspeed 9600 for the amp and have a MIT z-isolator plugged into it for the cd player. I plan to upgrade cords. I want to thank everyone for their constructive input. My main area of concern, however was opinions regarding upgrading the adcom gcd750 cd player. I am leaning towards a modified sony 9000es, resolution audio cd55 or arcam fmj23. Any other suggestions or feedback on the above? thanks
Dump the metal domed, harmonically thin 3.6's - way over-rated current hogs. Sorry, but someone's gotta say it... I can't even imagine how harsh 3.6's would sound running Adcom up front through a passive. Its frightening.
Seriously though, here's what I'd do: sell the 3.6's - some long time follower of Stereophile will buy them - and get a Coincident used that can be used with lower powered amps yet is relatively full ranged; sell the LLano because you don't need to dump all that current into the 3.6's massive crossover anymore and get a nice integrated tubed amplifier, say, a used AirTight ATM300 (since you go integrated you can take the LLano $ plus the passive $ plus a bit more and hopefully flag a ATM300 at $3500); dump the MIT and go with Goertz because you don't need the MIT to roll off the Thiels anymore (although Leoturetsky makes a good point above); if you can find any money then upgrade the CD, and only pump $ into the power when these other things are fixed. Good luck.
Wow. Really don't like the Thiels, Asa? Are Coincident speakers as clear as Thiels for the same price or lower? I'm just curious. I wouldn't give up my Thiels for anything for many reasons, clarity being one of them.
Here's my two cents. Thiels are a great speaker. There are combos of components that work well with them. Classe amps, mit cables, ARC tube pre along with correct room placement and toe in. When its right the sound is breath taking. It will take a lot of adjusting, but it will pay off. I've had 2.2's and still have 5i's and SCS's. It took weeks too get my 5i's placed properly. Don't forget that 1st reflections may also be part of your problem. Simple room treatments can cure them. Good luck!