It is a squeeze chamber (aka double chamber) design. So it is a small chamber diameter but is long. There are many sop MPs using this design: Meyer, Vandoren, Morgan, Ponzol, Barone, Selmer. Some use the same blank.
Part of the reason I'm interested is that I recently acquired a Buescher C soprano. With the supplied Buescher mpc (it's labeled with a Bb, not a C), the intonation was a challenge, and the timbre changed across octaves. Out of curiosity, I tried my Bari HR .68, which I use on my TT Bb soprano, and the intonation was greatly improved, along with the evenness of the tone across octaves.
The Bari is almost perfect. The only downsides are that it's loud, and just a bit bright. I'd like to try to get a little softer, darker tone. However, since I'd read that the C sops can be finicky with mouthpieces, I wanted to find out what other mpcs might have similar physical characteristics, so that I might narrow down the range of mouthpieces to try out.
The smallest chamber volumes I have measured are found in the Runyon Sop MPs. But most of them are high baffled and may not be the sound you are looking for. The Buescher C sop MP looks the same as the Bb one but is marked "C" and is smaller on the inside. It has a smaleer chamber voulme than the Runyons.
I have a "C" Buescher. Mine was extremely bad for intonation. After a lot of work, it up to terrible now. I can lip it, but prefer to play it unaccompanied.
You can try to stick some putty in you Bb MP to see if a smaller chamber volume works better for you. There is also a C sop section on this forum and a separate forum dedicated to C mel Tenor and C sop users.
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