Posted by John Swensen on May 24, 1999 at 15:29:22:
In Reply to: Re: queston for Eb tuba players posted by Brian Frederiksen on May 21, 1999 at 18:34:48:
Regarding that adjustable-cup mouthpiece that Renold Schilke made for Arnold Jacobs, could you tell us what rim popping notes the mouthpiece has when screwed all the way out and when screwed all the way in? By rim popping note, I mean the tone you get when you "pop" your palm on the rim with the mouthpiece off the horn and with nothing near the shank opening. The rim ends of my Conn Hellebergs, for example, pop pretty consistently at a G, an octave and a half below the C at which the shank ends pop. A slightly deeper custom version of a Helleberg that I made had a rim popping note about 25 cents below the G of the stock Helleberg.
Second, have you noticed any intonation differences for different cup adjustments? Offhand, I would guess that middle notes would tend to go sharp on a crecendo from pp to ff with the cup screwed all the way in, and would tend to go flat for the crecendo with the cup all the way out. This is based on some theoretical and experimental results reported by Benade in his Fundamentals of Musical Acoustics. (In brief, a deeper (larger volume) cup requires a bigger throat than a smaller cup to have the same rim popping frequencies and intonation characteristics.)
Third, I have seen a commercially-available adjustable-cup mouthpiece for trumpet advertised in the Brasswind catalog (about $100, which is pretty steep for trumpet mouthpieces).