Impressive, the range. I don’t know why but I was thinking it would only be able to make a few tones. I guess it’s really just an unwound bugle.
I’m definitely not an expert, but its my understanding that the length of the horn is what determines how many overtones are easily available.
I picked up a plastic PBuzz (really just a toy, but inexpensive) to experiment with heraldry trumpets, and the mouthpiece also makes a huge difference for accurately reaching those higher notes; its a lot easier to tighten up your embrasure when you have something to hold it all together like a small trumpet mouthpiece compared to the trombone-sized one that it comes with. Although that may be because I’ve had some experience with the trumpet.
Does this count as ancient Roman jazz?
The muta Harmon was invented a bit later.