C melody motorboating: what explains it?

[paulwl]

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.

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.

[stitch]

C melody players are familiar with "motorboating" or "warbling" - that truly obnoxious yodeling, cracking sound sometimes associated with the notes low Bb thru C#.

If only it were only on c-melodies...... :cry:

[paulwl]

I feel your pain, bro... :(

BTW, Mr. Moderator: I feel I mislocated this thread. I meant to chose the Sopranino, Bass, C-Melody and Misc. area, but it was very late (post-gig) and I was very tired. So tired that I saw this navigation text:
forum.saxontheweb.net Forum Index -> Sopranino, Bass and Misc.
and was unaware that I was actually posting in the Mouthpieces area.
Can the topic be deleted (both times) from Mouthpieces?

Thanks.

[Roger Aldridge]

Paul,

I wish that I could be of help to you; but, I don't have a theoritical understanding of this problem. My problems with warbling low B and Bb on my 1919 Conn curved neck c-melody were resolved by finding a mouthpiece with the correct length and chamber volume for my horn...as well as spending a lot of time shedding and performing on it. As a result, the low range on my c-melody speaks easily and cleanly even at soft dynamic levels. In fact, it takes less effort to play low Bb softly on my c-mel than it does on my True Tone alto!

From your message it sounds like adjusting the key pad heights might have done a number on you. But, darn if I can logically understand why. :? It certainly sounds like you did everything that could be done to stop the warbling. Let's see if someone is able to come up with an answer. I'd really like to know what it is!

Best Wishes, Roger

[soreliprick]

All i know is when I first got my '26 straight neck and used a red King vintage mouthpiece, all I could do was motorboat. Thinking it was the leaky white pads, I replaced them with Prestini Premium Black pads with resos, because I liked the black on silver look. Still the motorboating. Then I got a Runyon 6 and now I have to try hard to get mobo going. I've just recently found a metal Goldbeck 3 which plays even better than the Runyon, and looks stunning as well. And still the mobo is hard to get, unless I put the red King back on. So I would say it is strictly a mouthpiece thang...

[mark_m]

I've got the Morgan piece on my C-mel and I still need to work a little to avoid the warble. If the mouthpiece is set to the correct tuning, it's best, and certain reeds seem to help and others hinder...

I know the original question was regarding a technical understanding of this, I sure don't have it:) What it most reminds me of, however, is a phase cancellation effect, where two tones of nearly the same frequency create a beating. Onliest thing I can think of anyway.

It definitely improved with the Morgan mouthpiece.

[MojoBari]

I'm pretty sure I've seen a technical explanation of the instability, but I have not been able to relocate it or recall what it was. It could have been a dream or the brain cells were killed off by barley juice...

[rollen]

Does the Ernest Ferron book, The Saxophone is my Voice explain the causes of warbling? Going to have to dig it out.