Question:
Mark VI stuffy high A
I just finished a repad on a customer's Mark VI tenor. The horn plays great with an even tone throughout its range except for high A which is quite "stuffy" sounding compared to G, G#, Bb, and B. The key that closes when the G key is pressed matches the height of the rest of the upper stack, the neck octave pad opens the normal height, and the neck octave pip has been thoroughly cleaned. I don't know what else to try. Does anyone have any suggestions of how to voice the "A" more clearly without creating an intonation problem. Thanks.

Answer:
You might try opening G key some first. The low A is probably a bit flat anyway.
If that doesn't do it, try stretching a piece of pantyhose tightly over the pip while you play. Have someone help or tie it on the neck. If that fixes it, and I bet it will, post again for directions to permanently affix it.

Answer:
Just curious; was the A stuffy before the repad? I've found that many tenors suffer from this characteristic, which is usually a function of the badly-placed neck register vent. Since the hole is much too high for the A, it gets too near a displacement antinode and gets a lot of air rushing through it. I suspect the pantyhose trick just tends to defocus the airstream rushing through that tiny hole. A "workaround" at best, but if it does the trick, why not?
Toby

Answer:
Remove the high F# key and plug it! :D

Answer:
Originally Posted by kymarto Just curious; was the A stuffy before the repad? I've found that many tenors suffer from this characteristic, which is usually a function of the badly-placed neck register vent. Since the hole is much too high for the A, it gets too near a displacement antinode and gets a lot of air rushing through it. I suspect the pantyhose trick just tends to defocus the airstream rushing through that tiny hole. A "workaround" at best, but if it does the trick, why not?

Toby
It MAY be related to the following:

"Reynolds number" determines when laminar flow changes to turbulent flow. A higher number = more chance of turbulent.

Reynolds number is proportional to diameter for tubes.
Formula at

Laminar flow is far more efficient.

So we see a large rocket ducts packed full of smaller tubes, to increase flow.

I think a screen across an aperture has a similar effect. Think of the gauze incorporated into the nozzle of a kitchen faucet. It makes the water come out much less turbulent.

So, the gauze over the tone hole, or the flat-spring-lookalike permanent alternative installed inside the hole, quite possibly makes the air traverse that vent less turbulently, and MORE easily, even though the effective cross-sectional area is restricted.
turbulent flow changes to laminar

Answer:
Originally Posted by kymarto Just curious; was the A stuffy before the repad? I don't know. I neglected to play the sax in the condition it came in before dissassembling it. I won't make that mistake again.
Thanks Curt I will try your "trick".
Gordon, my friend, it never ceases to amaze me how your analytical mind works. You can actually take "STRETCH A PIECE OF PANTYHOSE OVER THE PIP" and make it complicated!:) :) :) :)
For additional reading on how Gordon complicates jtbsax's posts go to jbt's post on page 2 in this link.;) ;) ;) ;)
Seriously though. Thank you for discussing the underlying scientific principles that make this technique work. Even with this information it still seems "counterintuitive" to me to partially obstruct a vent in order to clear up a "stuffy" sound.

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That's why repair techs charge the 'big bucks'. They're experts at counter-intuitive. ;)
Hans

Answer:
Originally Posted by hansmartini That's why repair techs charge the 'big bucks'. They're experts at counter-intuitive. ;)
Hans Good one!:laughing:

Answer:
Clarifying A
Dull A is common on alto, tenors. Opening the G, as Kurt says, works. But that fix might have a drawback: one of my clients brought his Selmer 80II tenor back to me because the amount of opening on G needed to clarify the A led to an unacceptably "long throw" to get the G closed, hence he was stumbling during fast scale runs. He opted to live with the stuffy A, so we went back to original key heights.
However, on alto, the "throw" is not as long, so this fix works better on alto than tenor. My VI alto really improved with this mod.
Maybe we need a double vent in the lower 8ve like on the YBS-62.

Answer:
I was only suggesting a possibility, that along with contributions others have, may provide better understanding. Don't take it personally! I do it all the time,not just in response to you.
Better understanding surely makes a far better technician, and makes life a whole lot more interesting in general.
By presenting a possibility here, I am hoping somebody with a lot more expertise in the field may chip in and provide further clarification.
For all technical processes, if we know what we are doing and why, we do it ever so much better.

Answer:
Originally Posted by MusicMedic You might try opening G key some first. The low A is probably a bit flat anyway. If that doesn't do it, try stretching a piece of pantyhose tightly over the pip while you play. Have someone help or tie it on the neck. If that fixes it, and I bet it will, post again for directions to permanently affix it. In checking the G it was already a bit more open than the rest of the stack, and low A was even a bit sharp. I brought the G key down just a bit and then tried the "pantyhose" idea. It was fantastic. It worked just like Curt Alterac (MusicMedic.com) said it would. It brought the tone and timbre of the A into line to match the B and G around it.

In fact it worked so well I did some experiments with different colored pantyhose. Here are my findings"
Light colored panty hose --- produced a bright A with a "French" Marcel Mule-like tone
Dark colored pantyhose --- produced an A with a rounder, darker "Rascher-like" sound
Black colored pantyhose --- produced an A that definitely had a lot more "Soul" to it.8-)
Once I decide which color of sound to go with, I will invite Curt to post again and share with us how to make this repair permanent. By the way I want all of you techs on SOTW to come up with a very sophisticated sounding technical term for this repair, so I can list it as such on the bill and charge the customer another $100.
Ok Gordon, this is right up your alley......

Answer:
Originally Posted by jbtsax Gordon my friend, it never ceases to amaze me how your analytical mind works. You can actually take "STRETCH A PIECE OF PANTYHOSE OVER THE PIP" and make it complicated!:) :) :) :)
Well, this reminds me of a saying from the military.
The corporal talking to his men. "-You might find this matter very simple, but just wait until I have explained it!"
P.S: This is something that I wrote just to amuse.

Answer:
Originally Posted by jbtsax Once I decide which color of sound to go with, I will invite Curt to post again and share with us how to make this repair permanent. By the way I want all of you techs on SOTW to come up with a very sophisticated sounding technical term for this repair, so I can list it as such on the bill and charge the customer another $100.
OK, here's what I do to make this fix more permanent.
The problems with just stretching pantyhose over the pip and tying it are two fold. First it's unsightly. Second it makes the octave pad leak as the air travels through the grooves in the pantyhose. I often do a slight modification to the pip with a triangle reamer before I start this but it's not always necessary.
1. Tie the pantyhose over the pip.
2. Stretch the pantyhose so there are only about 5 strands going over the pip.
3. Get some 5 minute epoxy and mix it up. Use the clear kind like this:
4. Add heat to the epoxy via a hot air gun of some sort. This will thin the epoxy and allow it to mix better. Heat also removes the air bubbles and makes the epoxy set very hard.
5. Put a little epoxy on the pantyhose make sure to get it on the edges AND in the middle over the pip.
6. Quickly, hold one hand over the large end of the neck and blow in the small end. The epoxy on the fibers over the hole will blow off but the remaining epoxy on the fibers will strengthen then and keep them from fraying.
7. Make sure that the epoxy fills in the pantyhose grooves and is not in the pip.
8. Wait. Wait. let the epoxy set hard.
9. Cut the pantyhose from around the edges of the pip leaving only a screen over the pip and the entire pip cover with pantyhose.
10. Install a new pad that will now seal on the epoxy layer.
11. Play test.

Answer:
awesome.

Answer:
Thank you Curt. "You Da Man!" Let me put in a plug here for Curt Alterac
Curt is not only on the leading edge of techniques and materials to recondition professional saxes both old and new to play better than when they were made, but what impresses me the most is Curt's willingness to share with others what he has taken the time to learn in his clinics, workshops, articles and on this website. He even makes it fun to learn when he is giving a clinic. For all the above reasons and many more, Curt Alterac is a real class act IMHO.
P.S. I am still trying to imagine the drunken party where a sax player put some woman's panty hose over the neck of his saxophone and discovered the high notes sounded better.

Answer:
In response to Gordon's reasoning:
I agree that it is useful to understand the physics of the phenomena. But do the math with the actual numbers, and you will find that extremely high (supersonic) velocities are needed to get turbulent air flow through the pip. So I think one can rule out that idea.
The panty hose divides the original single channel (pip) in a number of smaller, very resistive channels - the resistance of a channel increases dramatically with reduced diameter. Therefore it is physically much more plausible that the air flow through the pip is strongly reduced, just as mosquito gauze in the window reduces ventilation.

Answer:
Originally Posted by vries1 ..... But do the math with the actual numbers, and you will find that extremely high (supersonic) velocities are needed to get turbulent air flow through the pip. So I think one can rule out that idea. Originally Posted by vries1
....
I'll take your word with the math, but before we leave it:
1. Did your math take into consideration the turbulence-facilitating effect of the sharp or relatively sharp edges at the ends of those vents? This effect could be much more significant that what the math actually calculates. (If as a flute player I am producing a rather non-turbulent airstream from my lips, I can easily make it very turbulent by allowing my upper teeth to intrude slightly into the path of the air entering my lip aperture.)
2. And did it take into consideration the turbulence-inducing deviation of the air round the pad above the vent. (This is so significant on clarinet, that using a rounded frustum-shaped cork pad makes a huge difference to the venting effect.)
3. And did it take into consideration the rapidly oscillating nature of the flow of air in and out of that vent? Intuitively, I think that oscillation would greatly increase turbulence.
4. A lot of air does oscillate at speed in and out of those octave vents at times. Have you done the math to actually calculate the speed?
May I suggest that with these considerations, the air may well be on the borderline of being turbulent.


Answer:
Originally Posted by abadcliche awesome.
I can't find words to agree more. Thank you Curt--and all the other tech dudes on here!
A strip of nylon and some duct tape has just fixed not only the ridiculously stuffy high A on my tenor, but it seems to iron out the intonation in the A-Bflat-B-C area too.
Curt's permanent fix sounds cool, but I'm imagining two small doughnuts made of metallic tape, cut to fit the diameter of the pip pedestal and with a same sized piece of metalic gauze sandwiched in between. This could then be simply stuck over the pip pedestal. Might work.
Here's the thing though (and I'm not sure whether this clarifies anything Gordon is trying to explain:? ;) , but I have to stress that, with my horn, this is a mouthpiece thing too. With a really big chambered piece like my scooped out NYWW B5 the problem goes away too.
SotW is great!!!
Cheers,
Rory

Answer:
Fluid dynamics indeed gets very tricky when you go into detail, and the presence of sharp edges can be one of those nasty details. (And what about pointed sticks? :wink: ) But I am not so sure that that's a relevant factor here.
I saw the question as a recreational physics problem and I did not spend my Sunday afternoon building a full numerical simulation. I just wanted to share with you pro musicians and (probably) amateur physicists the reasoning of a pro physicist, albeit not in fluid dynamics. Hey, we wouldn't happen to have a fluid dynamics Ph.D. online would we??
:confused: