Smooth and dark cables?

What lines could help dampen somewhat excessive sibilance in a system of very nice high end components that should be smoother in the upper mids. I have done all the room work that can be accomplished without serious spouse issues. As a very long audiophile I know philosophically cables shouldn't be used for tone controls but in this case it's my only choice. Have been thinking Transparent but would love some experienced suggestions.
Suggest you ask over at TheCableCo dot com for advice.
I would personally say take a test run with Cardas Parsec. they are not at all Smooth and dark, but they have a magical way of sweetening the response.
Like some college kid playing violin suddenly sounds like Oscar Shumsky.. Amazing.
Sounds to me like the Cardas Golden Cross would be the
ticket. Very smooth and warm with a laid back kinda vibe.

Liz...I'm going to try some of the Parsec. I was a Cardas
dealer for many, many years and George really knows his way
around. Always a big fan of him and his company. I got
away from Cardas a few years ago when I found and tried the
Grover Huffman cables, but have been yearning to try the new
lower priced Cardas.
Aforementioned Cardas Golden Cross, Kubala Sosna Emotion, MIT/Transparent, Fusion Audio Romance, Stealth PGS should be a good start.
Tara Labs
01-14-14: Tbromgard
Tara Labs

Tara Labs smooth and dark??? That has not been my experiences.
Not wanting to start a flame war, but IMO simply cables simply won't make that much of a difference.

If you really want correct for room deficiencies based on actual data and not by guessing, a good room correction product (hardware or software) will provide full spectrum correction based on sampling your existing environment.

I have experience with both Dirac Research's RCS software. They have a new, low cost version for stereo. If you are playing digital files from your computer, this product does an amazing job.

If you are using both analog and digital inputs, need balanced I/O and/or just prefer a hardware device the DSPeaker appliance also works very well. As an added bonus, the device can be used as a DAC and (very) simple preamp, if needed.

Back to your regularly scheduled programming...
I wonder if in your room adjustments you covered the base, so to speak. What you use for footers and what your speaker rests upon can make or break the sound you get. I tamed a bright top end by ridding myself of some flagstone and use a maple butcher block upon which my speakers rest, using metal spikes on metal coasters. Just removing the coasters is enough to dull the sound, so experimentation is warranted.

As for cables as tone controls, I've found that the cables that interfere the least, produce the best sound, regardless of where I start from, be it bright or dull. That sibilance can be a result of a type of smearing in that region (a lack of coherence) and lead one to believe that it's too bright and needs even more smearing, or dulling of the sound to tame it. A common mistake but one made all too often.

As Elizabeth suggests, I'd get in touch with and seek their advice and the use of their lending program. Good luck.

All the best,
Thanks for all the comments and advice. Have decided that in fact cables are not the solution but that room treatment would be of great benefit. I'll have to work on that one.
My original Cardas Crosses are fairly dark and rolled off.
Have decided that in fact cables are not the solution but that room treatment would be of great benefit. I'll have to work on that one.
I agree cables should not be used as tone controls. Besides room, also check synergy between your components.

If you want to try cables, check out SoundString. It's a touch on the warm side of neutral and inexpensive. I had a full loom years ago on several different systems. They recently released a higher end model that is more neutral and extended and also more expensive.