Posted by Klaus on March 04, 2002 at 22:38:15:
In Reply to: Re: Enlarging the Throat on Conn Helleberg posted by Chuck(G) on March 04, 2002 at 20:17:51:
As often told of I have opened up quite a number of of back bores on my various mouthpieces. But mostly I have let the throat areas stay untouched.
That is because I have bought the mouthpieces, that I trusted to be well made. That I have my own ideas on backbores, does not make me independent of good design and craftsmanship, when it comes to rims, cups, finish, and plating.
Cup volume and shape are important parameters, but maybe even more important for a smooth sound is the right transition from the cup into the narrowest part of the throat. There shall be no edges, as they will provoke turbulences, that will introduce unwanted resistance. And unwanted overtone components.
From Leo Sørensen, solo-euph in our Royal Guard Band and a former band mate in our partly common amateur youth, I learned, that the length of the cylindrical portion of the throat is a very determining factor.
If the cylindrical portion is long, it determines intonation and flexibility so much, that it diminishes the player's level of control. The slotting is pronounced, but if the slots are wrongly placed, there is not much one can do about it.
So as I want a high degree of control, I have had to make a conical opening of the cylindrical throat portion from the backbore side. My biggest problem has been to get hold of the right tools. I have not been able to buy any of them. Fortunately I have had been able to loan some reamers. The one used for opening throats has been a long and narrow one with a Morse taper. But it must be noted, that the narrowest diameter at the point, where the throat and the lower cup meet, mostly has not been altered.
Aside from the crimes committed on my horn mouthpieces, the only mouthpiece throat I have opened from the cup side, is that of the Denis Wick 4AY, that I use for my B&H Imperial Brit style baritone, my Kanstul G baritone, and my Hawkes G bass bone. All have tenor tromb sized receivers, but I wanted them to give more sound, than the original 4AY would allow for.
Douglas Yeo somewhere on his site wrote, that he had a special version of his signature mouthpiece made for his bass trumpet work. I mailed him for an advise how to order something similar, as I am very satisfied with the Yeo signature for my euph and my Bb bass bones.
DG replied me kindly, but I did not like his advice: to go to one of the renowned mouthpiece makers and have hime make a replica of the Yeo signature cup mounted on a tenor tromb stem.
My idea was to have Yamaha use the computerized formulas, that they surely still have kept from their work for Douglas Yeo. But my experiences with Danish and German Yamaha management have not been encouraging. One certainly has to know exactly which strings to pull to avoid knocking solid wooden heads. Not to say brick walls. (Things may have changed since 1996!)
Klaus
PS: The horn mouthpiece alteration have not really been that criminal. The results are still in use.