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Distinguished SOTW Member/Sax Historian
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Discussion Starter #1
I own one of the few Conn C melodies ever made with a curved neck AND microtuner (#55xxx, gold plated).

The mysterious thing about the horn is that the palm notes - top D and above - go progressively flatter with every mouthpiece and at every tuner position!

Complicating the problem is the fact that the top tenon of the horn was resoldered about 2mm further up the horn than it should be, leaving a grey ring.

Could an extra 2mm of length throw out the palm notes? Or is there some acoustic weirdness going on with the neck? Conn did take it out of production very soon in favor of the straight neck.

Putting a straight neck on helps the tuning, but not that much. Neither did opening up the palm key heights.

Any insights?
 

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Distinguished SOTW Technician
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own one of the few Conn C melodies ever made with a curved neck AND microtuner (#55xxx, gold plated).

The mysterious thing about the horn is that the palm notes - top D and above - go progressively flatter with every mouthpiece and at every tuner position!

Complicating the problem is the fact that the top tenon of the horn was resoldered about 2mm further up the horn than it should be, leaving a grey ring.

Could an extra 2mm of length throw out the palm notes? Or is there some acoustic weirdness going on with the neck? Conn did take it out of production very soon in favor of the straight neck.

Putting a straight neck on helps the tuning, but not that much. Neither did opening up the palm key heights.

Any insights?
The resoldered tenon if it is 2mm out, will definately affect tuning throughout all registers. if the straight neck doesnt help that much then it could be that you need a different mouthpiece - what mouthpiece are you using at the moment?
 

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Reckon it's the tenon---it's a crucial point in the cone regarding tuning issues, plus the fact the actual joint is going to be weak--- not much holding the pieces together there.
 

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Discussion Starter #4
The resoldered tenon if it is 2mm out, will definately affect tuning throughout all registers. if the straight neck doesnt help that much then it could be that you need a different mouthpiece - what mouthpiece are you using at the moment?
I tried a few of every type - stock Conn barrel chamber, a few alto mpcs and a few tenor mpcs. The fault always replicated.
 

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Just a guy who plays saxophone.
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Maybe someone was trying to stretch it out to a B Melody...haha. Sorry, couldn't resist! I know nothing about the physics of sound.
 

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Distinguished SOTW Tech/Forum Contributor 2007
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how far back is the neck octave pip?

i had a 1940's buffet alto that had wretched intonation up high and it was driving me insane, i noticed a ponzol neck played really well on it and that it stuck out of the tenon 1 or 2 mm, thinking that this was the issue, at some point later i noticed that the octave key on the neck was 1.5 inches farther back on the orginal neck, (almost right up against the end of the mouthpiece) than the modern ponzol...

personally i think more is made out of the mouthpeice chamber thing should be and most of the tuning problems on old horns has more to do with the octave neck location, than the mouthpiece chamber....

this is purely my opinion based upon my own experience with modern mouthpieces on vintage horns and trying different necks, i make no claim to be able to explain this in pseudo acoustics speak, this just what i have nocited...
 

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This is an interesting problem. An extra 2mm is a substantial amount with consequences on the tuning and playing behavior.

The problem here is that lengthening the tenon should raise the pitch of the palm notes, not lower them. I made quick approximate calculations and that could represent approximately 10 cents. Therefore, it is possible that the modification on your saxophone is an attempt to fix the flat palm notes problem. If this is indeed the case, resoldering the tenon back to the original position would only make the problem worse... Before making such an attempt, you should maybe make a few experiments on another horn, just to verify experimentally what to expect from a similar modification.

As for the neck pip, you can easily test its effect by playing the palm notes with and without the register key and take note of the small frequency shift.
 

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Discussion Starter #9
Fascinating...

I'll experiment with the 55k's curved neck on my other Conn (116k) and the electronic tuner when daylight permits.
 

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What, no electricity or candles in your 1937 house? :)
 

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Discussion Starter #11
It's an apt house with 1937 and earlier vintage neighbors, who have lawyers. These lawyers make money by writing me when the neighbors hear me playing late at night.

Anyway...here's a summary so far:

116k horn + 116k neck (straight tunable) - palm notes OK.
116k horn + 55k neck (curved tunable) - palms slightly flat, but tolerable.
55k horn + 116k neck - palms slightly flat, but tolerable.
55k horn + 55k neck - palms too flat. I would say E and F are about 40c flat, at best. That's nearly a quarter-tone off.

Still haven't gotten the electronic tuner up and running. Not looking forward [rolleyes]

Antoine, I would love a layman's explanation of how lengthening the tube above a tonehole makes its note sharper. (If, in fact, that is what you claim above...I may be misunderstanding!)
 

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Although I am not prepared to argue with a PhD, it is logical to think that if the tenon has been raised, the length of the horn has been increased by 2mm....the palm key notes being further from the mouthpiece than in it's unmodified form....therefore, if the tube is, in effect longer, why is the pitch of the palm key notes not lower....ie. flatter.
Moving the tenon will surely effect the pitch of the nearest tone holes to a greater extent than those further down the tube....an intonation progression based purely on percentage of length.
 

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Discussion Starter #13
It is logical, prima facie, to think so. What I hope to understand is the factor or principle that makes this case different.
 

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Antoine, I would love a layman's explanation of how lengthening the tube above a tonehole makes its note sharper. (If, in fact, that is what you claim above...I may be misunderstanding!)
Here is an attempt at a layman's explanation.

Suppose we have two instruments, one with a tenon longer by 2mm but everything else is the same. In both case, you'll first tune your instrument as usual, on a first register note. In order to be in tune on the tuning note, you'll push the mouthpiece further on the cork on the instrument with a longer tenon, and you'll push it by more than 2mm, possibly 3mm, as a consequence, the toneholes are finally closer to the mouthpiece tip in the case of an instrument with a longer tenon, their pitch is higher.

I made calculations and simulations to double check this. An experimental verification would be good. What about using one horn and see the effect of not entering the neck fully? Anyone can try it?
 

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Discussion Starter #15
So human overcompensation is the missing variable?

I'm pretty sure I wasn't overcompensating with the curved tuner neck. I did try several tuner settings.
 

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Distinguished SOTW Tech/Forum Contributor 2007
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are the two necks of a similar (or same) lenght, and is the octave pip in the same relative location on the two necks? my guess is that it is further back on the 55 neck (closer to the mouthpiece end of the neck).
 

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Here is an attempt at a layman's explanation.

Suppose we have two instruments, one with a tenon longer by 2mm but everything else is the same. In both case, you'll first tune your instrument as usual, on a first register note. In order to be in tune on the tuning note, you'll push the mouthpiece further on the cork on the instrument with a longer tenon, and you'll push it by more than 2mm, possibly 3mm, as a consequence, the toneholes are finally closer to the mouthpiece tip in the case of an instrument with a longer tenon, their pitch is higher.


I made calculations and simulations to double check this. An experimental verification would be good. What about using one horn and see the effect of not entering the neck fully? Anyone can try it?
thank you i was scratching my head after your intitial post but that makes perfect sense. thank you for that...
 

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So human overcompensation is the missing variable?

I'm pretty sure I wasn't overcompensating with the curved tuner neck. I did try several tuner settings.

No, it's not overcompensation. My attempt at explaining the effect may not be very good. You need to understand that my approach to this sort of question is to make a mathematical model of the problem (wave equation) and to calculate the resulting resonance frequencies. I do that with a computer program. This does not translate easily to layman's terminology.

Still, to me, this whole issue triggers the need to make a number of experiments, I never trust too much my own calculations.

Are you looking for a permanent fix to the problem or only to understand the cause of it?
 

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Although I am not prepared to argue with a PhD, it is logical to think that if the tenon has been raised, the length of the horn has been increased by 2mm....the palm key notes being further from the mouthpiece than in it's unmodified form....therefore, if the tube is, in effect longer, why is the pitch of the palm key notes not lower....ie. flatter.
Moving the tenon will surely effect the pitch of the nearest tone holes to a greater extent than those further down the tube....an intonation progression based purely on percentage of length.
Captain Beeflat, You are absolutely right. The PhD that neither of us wants to argue with tried to out-logic himself, and forgot to mention that when he made his quick complications he included pushing the mouthpiece in on the cork to compensate for...wait for it...The fact that lengthening the tube by 2mm makes the instrument pitch lower! :whistle:

Like this one time, at band camp, I like, didn't put the neck in all the way, like when I put my saxophone together. I like, couldn't understand why I like, had to push the mouthpiece in like, so far to play in tune...:TGNCHK:

It bothers me when smart people try to go above the logic, reasoning and common sense of us lowly peasants, but it is fun to play along like we don't know anything...
 

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It's an apt house with 1937 and earlier vintage neighbors, who have lawyers. These lawyers make money by writing me when the neighbors hear me playing late at night...
Paul - I understood completely. For the first time in my life I have the perfect neighbours. On one side is a quite deaf 90+ elderly lady, and on the other side is a young family who like hearing me play jazz, and dismiss my "Was it too loud/late ?" with constant apologies about their kids starting WWIII. I must be in heaven... (the 'Lapsed Methodist and Failed Buddhist' section :cry:)

Back on topic, whenever someone says anything like "Here is an attempt at a layman's explanation..", I just think "patronising *%$£!*%" and head for the pub :tsk:
 
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