Piano and Trumpet can sound bright

Stage musicians as a matter of fact usually won't use instruments that can be irritating or harsh. Obviously with Miles Davis it's not the case.

The speakers mentioned
1. are not tube friendly in general
2. very sensitive to the amplifier choice (I'd probably use them with such amps as Creek 5350, Unison Unico, Arcam, Nad C372 and other shy and polite amps).

Since quicksilver silver90 is nowdays 'endangered', I'd recommend to keep this treasure and replace speakers. Have Totem Forests floorstanders for very cheap(shame to post on A'Gon for that price). Will match Silver 90 like butter'n'jelly. I guarantee that for this recommended upgrade you'll get money instead of spending from selling yours and getting mine.

Could be some of the above (ICs, diffraction, room acoustics), but my main suspiscion is the aluminum tweeters. Miles' muted horn can be excrutiatingly sharp on some systems I've heard. I have't yet met an aluminum tweeter I've liked. But for a first try I'd contact Jim Goulding and order a pair of his anti-diffraction pads. They are inexpensive, and although might not completely alleviate your problem, may help a lot. He might even have a return policy.

Kimber and metal dome tweeters are not a match made in heaven. Change the speakers or go to a smoother cable.

Yep, tweeters and cables. Trumpet is quite bright by nature of its sound, but I know what you mean. And piano is not bright.

Hi,
Unsound, the jazz clubs I attend are`nt amplified and regardless of the players or seating the sound of the horns are as I described. Lucky me I suppose.
Best Regards,