Posted by Ken Herrick on October 26, 2001 at 18:06:04:
In Reply to: Taper and intonation posted by Chuck(G) on October 26, 2001 at 15:45:59:
Renold Schilke did a considerable amount of study on the effects of variations in tapers on intonation. The lead pipe is "the" critical area, but many factors have an influence.
Many years ago Conn did some studies on the effect of placement of braces. Placing a brace at a nodal point can have quite an effect. Leaky valves tend to be very detrimental.
Old Besson BBb tubas always seemed to play better in tune once they got a good dent just above the collar joining the bell and bottom bow!
I have been doing some experimenting on damping on a Conn 5J. This particular example is in very good condition but seems to have been very poorly put together. Circumstances rule out rebuilding it, but by cutting up some synthetic wine corks and carefully wedging them into place I have turned this one from an absolute dog which just would not respond in the lower register into a reasonable instrument. The response characteristics overall have improved greatly. It used to be rather like a pair of cymbals which continued to ring for ages. One note would continue into the next.
In a couple days a saddle maker friend and I are going to do some experimenting with shrinking some leather onto the bell to see if further improvemnt can be made. I have already found that puting a leather guard over the bottom bow has had a positive effect. There are also the benefits of giving some scratch and dent protection and making the instrument much easier to hold as it no longer slips around.
I'll include a link and address for an interesting article by Ren Schilke.
http://www.dallahttp://www.dallasmusic.org/schilke/brass%20clinic.html