Posted by Frederick J. Young on May 20, 2001 at 19:23:37:
I have been calculating the frequencies of the open and valved tones on various instruments such as trumpets, flugelhorns, alphorns and on a Melton F tuba. I use solve the Riccati differential equation describing the acoustical impedane seen by the players lips. This is now a common practice which I devised more than 40 years ago and published in ACUSTICA. To get the dimensions of the trumpets, I filled them with molten lead. Then I dipped them in sulphuric & nitric acid until all of the brass was gone. A technicial the measured the dimensions with various micrometers. I am tempted to do the same to an old York CC tuba but hate to waste one. The dimensions of the Melton tuba may not be completely accurate or it is a very out of tune instrument. I need the inside dimensions as a function of distance from the bell through out the instruments to and including the mouthpiece. I once tried to get them for the Nirshel CC tuba and was turned down. Since then I tested one of his F tubas and it played nicely except that it was very, very out of tune, even on the open notes. A true hunk of musical junk in my estimation unless one is a trombonist! I'd much prefer a Yamaha compensating EEb tuba.
In closing, is there anyone out there who uses a Gronitz double tuba? If so I would like to hear from you, bitte!
So far the best intonation was found on as Alphorn. Old's trumpets were also pretty good.