If you have acces to a parametric equalizer try these settings (3 peak bands)
I "handcrafted" them for my T90s a while ago. These tame the sibilances without losing "air" and retrieve a little bit of high-mids, which seem to be a little bit subdued. With these I find the T90s to be comparable to the T1s in some aspects such as impact.
They work very well with my set-up - thank you!