jazz drivers

like the sound off my sonus faber concertino, but they are a bit old, so the mids are a bit low...

All box low db speakers suffer this same aliment
Try wide band for real jazz music.

Like youve never ever ever heard it before.
Keep the woofers, trash the tweeters.
Go  6 or 8 inch WB,, add a   Be tweeter from Davidlouis if you go 8.

ZuAudio

Not saying it's your answer, but I listen to a lot of jazz on my KEF LS50's with a subwoofer. I like a warm, clear sound as well and am very satisfied, but also have not compared to other speakers. You might also consider adding a tube preamp as it will add some depth and warmth to the sound. 

I had been using an Ayre A7e integrated that I really like to drive LS50s, but there’s no practical way to add a sub, so I’m using an Oppo 205 and NAD M 22 amp with a pair of Velodyne HGS 10s and SMS-1 bass manager. The Oppo front end sounds surprising good, and the Oppo plays Blue-rays as well as being a Roon endpoint -- it replaced an ultraRendu and LPS 1.2.

re: "using an Ayre A7e integrated that I really like to drive LS50s, but there’s no practical way to add a sub..."

Just as a point of clarification, using powered subwoofers with Ayre amplifiers is a common practice.  I've used subs with both the Ax-7e and the Ax-5 for years.