Posted by Jay Bertolet on August 04, 1999 at 11:56:25:
In Reply to: Re: Re: Re: Re: Custom Mouthpieces posted by Doug Elliott on August 04, 1999 at 09:19:16:
My contention in the earlier thread was that any interruption in the smooth, consistent conical expansion of the overall tube, which starts at the throat leading out of the cup of the mouthpiece, would have detrimental effects on intonation, etc. So, I am under the impression that a gap of any sort in the receiver would affect this. Such a gap might produce desirable side effects as well and the people at Dillon's have convinced me that such gap manipulation can be useful. Also, if the end of the mouthpiece shank doesn't connect exactly with the leadpipe venturi point, that would also have an affect. And of course, the "step" which occurs when the mouthpiece shank ends must have some affect, in proportion to the thickness of the metal at the end of the mouthpiece. There was discussion that some mouthpiece manufacturers bevel the end of the mouthpiece to eliminate this "step" but it seems to me that this procedure wouldn't fix the problem because it would still interrupt the consistent expansion of the overall tube.
Your idea of standardizing the length which the mouthpiece extends into the receiver is something I proposed as well. Actually, my idea was to standardize the inside dimensions of receivers and the outside dimensions of mouthpiece shanks so that a proper union could be achieved while still leaving room for individualization of the actual backbore size. I would be curious to know your thoughts on whether such a "perfect union" affected the playability of given instruments appreciably. Also, I'm wondering if I'm chasing a wild goose by putting such a high priority on looking for a consistent expansion of the overall tube. Does the smooth and gradual consistency of said expansion have a positive affect as well?
Not that I disagree with the folks at Dillon about the gap business but, as they explained to me, at least 3 of my tubas don't have a traditional receiver at all so gap manipulation is not a practical option for my situation. It sounds like your procedure might be more effective for what I'm looking for but I still need to know if my "Rube Goldberg" science is worthwhile to pursue. Any information you can provide would be helpful, to say the least. Thanks for your input!