Since I have had the most exposure to this concept (there when the horn was being laid out), I wanted to see if I could add some of Matt Summer's own thoughts about the "why" of this design. Keep in mind he is also a Bass Trombone player and has MANY years (40+) playing compensating euphonium. In answer to "Why is this a non compensating instrument?", Matt replied on Facebook yesterday:
"That’s the whole point to it.
Fully chromatic where needed, without the significant backpressure that can be problematic for fast changes in tessatura.
Think of a mid to high range line interspersed with FF low C pops. ( ex. Fountains of Rome)
Getting loud low range to speak quickly on a compensating system can be problematic with limited time to set up for the note.
This should speak much more easily.
A happy side effect of the non-compensating system is that the valves have significantly less mass to move up and down.
You can go with lighter springs, or opt for potentially faster action with the same power springs we’re used to with compensating instruments.
This isn’t a replacement for compensating instruments, but an alternative that addresses some of the shortcomings (long valves/backpressure) inherent in the familiar designs.
Yes. The low fingering are different from the octave above. But so are the fingerings between the octaves above.
It’s a very slightly different mindset, but totally transparent until used.
Sure, one can find combinations that are out of tune, but just like you don’t play a C with 1-3, there are several options that DO work.
The benefit of the new non-comp valve set should be evident with the first fast passage."
I hope this helps answer some questions. If not, contact Matt to get more feedback. He has a VERY clear idea of why this is good and I expect he has the creds to back it up.
Doug