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 TheCableCo.com and seek their advice and the use of their lending program. Good luck.
All the best,
Nonoise
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 TheCableCo.com and seek their advice and the use of their lending program. Good luck.
All the best,
Nonoise