paulwl
09-07-2003, 07:23 AM
C melody players are familiar with "motorboating" or "warbling" - that truly obnoxious yodeling, cracking sound sometimes associated with the notes low Bb thru C#. Various causes are usually given - the wrong mouthpiece chamber size or length, too soft a reed, a leaky pad somewhere, the want of a baffle-type object like a cork in the bell bow, or my favorite excuse: sunspots. :wink:
What I'd like to hear is at least an approach towards a scientific explanation. It's got to be something to do with the unusually slender bore, combined with the invariably opposing-side low B and Bb toneholes.
Why do I care? Well, today I got out my 1936 Conn 8M in preparation for a dixieland job. As it typically plays sharp for me below low C, I tried an experiment: I built up the bumper felts on that key as well as B and Bb. Whammo! Immediately the notes, although now reasonably in tune, played stuffy and could not be attacked or crescendoed without motorboating.
All in all, I tried 2 necks (curved and straight), 6 different mouthpieces (yes, vintage too) and probably 12 different reeds, as well as a wine cork. NOTHING got rid of the motorboating. A rope light revealed no obvious leaks. I finally got it under control enough to take on the gig, but I honestly don't know how - the horn was fighting me every step of the way. Low B, the weak note on any split bell saxophone, remained essentially unusable.
Is there some acoustic principle at work here I don't understand? Is the C melody bow and bell vulnerable to nodes, or colliding air currents, or something? Would I have done better to glue in tonehole liners, rather than close down the key heights? Can a knowledgeable tech do anything I couldn't do by just bashing on setups?
Any insights, preferably from experience, appreciated.
What I'd like to hear is at least an approach towards a scientific explanation. It's got to be something to do with the unusually slender bore, combined with the invariably opposing-side low B and Bb toneholes.
Why do I care? Well, today I got out my 1936 Conn 8M in preparation for a dixieland job. As it typically plays sharp for me below low C, I tried an experiment: I built up the bumper felts on that key as well as B and Bb. Whammo! Immediately the notes, although now reasonably in tune, played stuffy and could not be attacked or crescendoed without motorboating.
All in all, I tried 2 necks (curved and straight), 6 different mouthpieces (yes, vintage too) and probably 12 different reeds, as well as a wine cork. NOTHING got rid of the motorboating. A rope light revealed no obvious leaks. I finally got it under control enough to take on the gig, but I honestly don't know how - the horn was fighting me every step of the way. Low B, the weak note on any split bell saxophone, remained essentially unusable.
Is there some acoustic principle at work here I don't understand? Is the C melody bow and bell vulnerable to nodes, or colliding air currents, or something? Would I have done better to glue in tonehole liners, rather than close down the key heights? Can a knowledgeable tech do anything I couldn't do by just bashing on setups?
Any insights, preferably from experience, appreciated.