need more smoothness

I agree that silk's are far less hostile than metal tweeters. However, the crossover slope shouldn't make a bit of difference in the presentation of the tweeter. The crossover has everything to do with the integration of tweeter and the mid/bass driver. The tonality of the tweeter is inherent in it's design and materials and how loud it is in comparison to the loudness of that mid/bass driver (talking about relative efficiency here).

Enjoy,
Bob

Once upon a time my rig suffered from tonal hardness (aka distortion) of upper register piano, soprano sax, flute and, as you mentioned, violin. Turns out it was the preamp. Switching from a Forte 44 to a Threshold Fet ten solved the problem across the board. So maybe your speakers are not to blame. Painlessly conveying the tough tones may be a job for finer, less distorting electronics.

Very interesting stuff Cellorover! In my limited experience, I always found that I preferred speakers which turned out to have silk/fabric tweeters. Though that is not to say that metal dome tweeters cannot be smooth, for example the nautilus line with good (smooth) amps.
As for the Finns and their research: do you think we could get them to do the same research with tubes vs ss!

It's a matter of the personal tastes that are currently somehow statistically spreaded throughout speaker manufacturers.
The largest differences heard in speakers in top-end are in tweeter designes. I prefere aluminium dome and someone would prefere soft textile.
I think to agree with Gmood1 that basically you havn't got the speaker you realy want.

I can't believe it. I just went to the Bowers and Wilkens website and that's what they recommend... stick felt on their speakers!