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How do you correct octave key sharp notes?

12K views 62 replies 19 participants last post by  JayeLID  
#1 ·
I have a nice chinese tenor that I bought to learn repair on (I'm not touching the Yani!). It seems pretty well built, but I have one main problem I don't know how to solve. Everything mentioned below was done keeping embouchure as constant as possible, and tests were repeated multiple times, with vastly different mouthpieces (Link STM 6* and Yamaha 4C). #3 ZZ reed.

Playing up the scale from low to high, intonation is very good until I get past G with octave key. The A with octave key goes about 10 cents sharp, B with octave goes about 40 cents sharp, C# with octave goes about 50+ cents sharp, palm keys also around 50 cents sharp with octave. If I play all open (C#) and tune to it, then hit the octave key, the high C# goes 50 cents sharp. Let off the octave key and the all-open C# is perfect again.

All of these notes without the octave key are very close to being perfectly in tune. It is only with the octave key, and only above G, that the notes go way sharp.

I experimented with a half moon in the G tone hole, and it corrected the A with octave but made the A without octave flat. The half moon did nothing for the other sharp octave notes.

What could be the problem? The octave works well enough so I'd guess the pip is close to the right spot. There are no dents in the neck, and it fits well into the sax body. I've tried installing the neck slightly high in the tenon (not fully seated in the body) and it just made everything flatter. Whatever the issue is it only affects the octave notes above G - all notes without octave are fine, and notes with octave key up to G are fine.

Any suggestions?
 
#2 ·
Hmm. The cheapest saxes usually have quite a heap of things wrong with them. Not just mechanical, but also in acoustic design. That's what I suspect. It could be something simple like the exact taper of the neck. Or the diameter of the neck's octave vent.

Try to copy a Merc without knowing why each part and dimension is like it is, and you are unlikely to get a Merc.
 
#3 ·
The neck is the problem, try another neck and see if that doesnt cure it.
 
#6 ·
It sounds very much like it's the octave pip, I would experiment with the diameter, the length of the tube into the neck and (if all else fails) the position. As you are learning repair, this could be a good lesson!

As Saxxsymbol says, it may be worth trying other necks, you might just get lucky.

I have a nice chinese tenor
Didnt know they made them.
You'd be surprised what they can do these days.
 
#9 ·
What could be the problem?
The horn in question is complete garbage. But yeah, messing with the octave pip might be worth experimenting with given the situation. As you've discovered, crescents aren't going to work worth a damn with the octave notes unless both octaves are equally out of tune; only palm/side key, lower bell notes.

For those that have moved octave pips: if it's not the diameter of the octave pip that's causing the problem, but positioning, would moving it further away from the mouthpiece end act to reduce the sharpness?
 
#12 ·
The same "sleeve insert" fix that people use for "*" Buescher necks may work for you -- i.e. an insert at the tip opening end of the neckpipe that flattens the high notes. If you do a search for Buescher True Tone intonation issues, it should pull up instructions/notes.

An octave key adjustment which could work (it sounds like) isn't doing the trick, so the next logical step is either an alternate neck or an insert. An insert is generally speaking less invasive and in practice a simpler solution than trying to alter the neck diameter. A larger chambered mouthpiece (another typical strategy for Buescher TT altos & C-mel's that are sharp from A up) may or may not help as well.
 
#23 ·
The same "sleeve insert" fix that people use for "*" Buescher necks may work for you -- i.e. an insert at the tip opening end of the neckpipe that flattens the high notes.
After some research I tried this with some vinyl tubing and it corrected the problem. (gee, does that mean that Buescher TT horns are "complete garbage" also?) Thanks for the tip! A few notes were borderline stuffy, and a few were a bit flat but within embouchure correction range.

The insert was a bit crude, so now I am thinking about a more refined and durable solution using a harder material so the resonance is not damped. I could turn an insert from brass, aluminum or plastic but I'm not sure how to get it tight in the conical neck area under the cork. Some TT owners used hot melt glue and heated up the whole neck area until the glue flowed. I could JB Weld the inside and build it up, but that's near permanent. One TT owner even glued a stack of pins around the ID.
 
#15 ·
Notes getting significantly sharper (way too sharp) from A2 and above is a common problem with a certain model and/or generation of Chinese saxophones (not actually just one specific model). This might be one of those. I haven't found a real solution for this. Changing the octave tube hole diameter in all sorts of ways never fixed the problem (on instruments that I've tried at least). It made improvements but long after maybe worse compromises took their place.
 
#16 ·
In the end- if you can find other necks that fit and try them out "you never know"; but that cuts both ways. You really do "never know" and shelling out for a neck- regardless of brand- is by no stretch of the imagination a sure cure or guarantee of change in any specific direction.

This thread on an octave pitch change on Cannonballs (fine horns- no slam intended) indicates that this is an issue with many of the new horn designs.

http://forum.saxontheweb.net/showthread.php?104347-Cannonball-Tenors-Sharp-Due-To-Short-Neck

Any number of threads on Buescher and other "classics" shows similar issues addressed by many intricate fixes sagely presented under a cloud of psuedo analytic science but amounting in the end to p-ligging in a less in-your-face way.

If it works for them, it works for them.

With most horns, at least for me, a few hours of playing and generally usually I find that I adapt and the issue goes away. If nothing else it's a cheap solution.
 
#17 ·
I suspect you've been given the wrong crook with the horn.
I've seen this a few times now with Chinese horns - an otherwise perfectly decent horn that has terrible tuning and tone problems...and they all disappear when the proper crook is fitted.
It probably occurs because each factory makes a number of seemingly identical models, but the body tube is a different design. Someone in the picking department makes an error and selects the wrong crook for the outgoing batch (I doubt that the horns are play-tested).

Stand the crook on a table with the tenon sleeve pressed flat against it and measure the distance from the top of the table to the centre of the bore at the mouthpiece end.
There appear to be two common designs of crooks knocking about - one will measure around 2 1/2 inches, the other around 3+.

Regards,
 
#36 ·
You know (aside from an immediate smile of recognition which you will understand), my first thought is to add that, surprisingly, at least one factory -- with which we're both familiar -- may actually do some playtesting. I buy many extra necks for my PRC lines, and although I often get a better neck from the batch of extras than is matched to the horn as packaged, more often the pre-matched necks perform better (by percentage of necks that are pre-matched, versus purchased loose), and this is does not seem to be due to tenon fit.

OTOH, I also somewhat suspect that, for example on altos where the tuning point is significantly further in from the neckpipe opening than on other modern makes, in the process of determining the bore there may have been (and still may be) a playtester with less than awesome embouchure.
 
#18 ·
Steven -

Mine measures 2-1/2 inches. The tone is pretty darn good everywhere, and the intonation without the upper octave vent is spot on.

So if they were supposed to put the 3" crook on mine instead, would that ONLY affect the upper octave vent notes? Because my horn has very good intonation everywhere below high A. Seems like a longer crook would be much like extending my present neck out of the tenon a bit - which affected every note (flatter), not just the upper octave vent notes.......?
 
#19 ·
The crook with the 3" lift isn't any longer - it just has a different bore profile...and a think a slightly different pip placement.
What I found was that although the wrong crook played in tune in the lower octave, the tone was slightly muted...and the upper register was all over the place from A upwards. I haven't tested it in the upper octave with the crook key closed.

Regards,
 
#22 ·
With most horns, at least for me, a few hours of playing and generally usually I find that I adapt and the issue goes away. If nothing else it's a cheap solution.
I play soprano mostly, so I am not unaccustomed to adjusting intonation with embouchure. The notes I'm dealing with here are not 10 cents sharp tho, they are 50-60 cents sharp. Unplayable for me.
 
#26 ·
The first iteration insert I used was pretty close to the prescribed dimensions for the TT, so I assume the owner of the TT had about the same issue as my horn - it was actually a bit too much correction for mine. As I said tho, this was simply a boilerplate attempt to see if this would address the specific problem I have. It did add a bit of stuffiness to a couple notes - I need to make an insert of thinner wall, the same length, and I'd like it to look more like a venturi then a chunk of hose shoved in a pipe.

Another approach might be to "roll-form" the neck section under the cork to evenly and smoothly reduce the inside diameter. I haven't figured out how to do that yet........... :)
 
#28 ·
Yes, exactly what I did. Using a tuner, the insert did not seem to effect the intonation of any notes except the upper octave vent notes. So basically the insert made the horn within 10 cents up and down the scale, but the notes with some stuffiness need work yet. The "new and improved" insert should help with those.........
 
#29 ·
Apologies to the tech community; feel free to avert your eyes...

I used a thin sheet of teflon sheeting glued onto a .3 mm strip of tech cork to make a 3/4 inch strip which I superglued inside the neck opening. I shaped the cork side so that it tapered into the neck tubing on the tenon edge (away from the neck opening where you place the mouthpiece). I figured the teflon is probably just as smooth as the brass inside the neck and if I ever want to get it out it pries out easily- but otherwise stays put with no issues.
Clearly you'd adjust the thickness of the cork/ teflon strip to suit.

If you want to try to sand it after it's in place the thickness of the teflon sheet (pretty darned thin) would be the limiting factor. A daubing of nail polish over the sanded areas would probably be suitably reflective as well in the event touch up without a do over was required.

As earlier- I make no assertion for any acoustically expoundable properties beyond that it worked for me on my 1927 Buescher True Tone with a stock neck which had run sharp in the top end. Was it the fix or had I simply gotten used to it? I think the stuff made a difference, your tests seem to indicate it works on your horn for you, beyond that any one else's mileage may well vary...
 
#31 ·
No, I DID use several strips of various thicknesses and tapers (for trialing the taper was simply accomplished in the shape of the strip as seen from above rather than by sanding the piece on the top) to determine the optimal volume displacement as best I could- but the final product was the .3 mm teflon cork and .015 inches teflon sheet by .75 inches sanded towards one edge strip I used which displaced the same volume as the strip I had been using for trialing. That final product was in annular shape just inside the neck opening flush to the exterior edge.

Aside from looking way less clunky, the ring seemed to play identically to the strip, so you could surely try a strip vice squandering the time on the ring. There's a lot less effort in cutting "exactly so" to ensure flush ends and the painstaking glue application involved is avoided.
 
#33 ·
1. From my limited knowledge of the acoustics of the sax, a site linked to seems somewhat misleading in what it seems to say. The (very slow) travel of the aid down a sax is a bi-product of how the sound is initiated at the reed. AFAIK it, and its speed, has no relevance at all to the sound production, tone, or pitch. Please, an acoustic expert, tell me if I am wrong. On the other hand, there is very small amplitude oscillation of the air up and down the bore in certain locations, creating the standing wave. A constriction may well have some affect modifying the speed of these, but possibly, an effect in modifying the degree of turbulence within the bore, which takes me to the limit of my acoustic awareness. Kymarto and others may know more.

2. Reflection of something inside the bore, against the inside of the body tube, is not, to my knowledge a phenomenon that occurs at all. A some locations (pressure nodes) air is oscillating (in and out of open tone holes, and along the bore in that vicinity) as mentioned. In others it is similarly oscillating with the opposite phase, such that between these areas, there are locations (pressure antinodes) where there is oscillation of air pressure. and all that constitutes the standing wave that results in us perceiving sound. No mention of reflection.

So the Teflon probably has no function whatsoever. However any soft material lining the bore, including the closed pads themselves, may well have an effect in damping the pressure oscillations, hence interfering with the formation of the standing wave. I think this may contribute to the so-called "resistance" or "back pressure" that a player wants I don't know. If so, it may make a difference whether (the bulk of it) it is made from a soft material such as Teflon or cork, or made from a hard material such as metal.

The surface texture may have a slight effect on the resistance of the air against the bore material itself, i.e. effect the the "boundary layer". That in turn may slightly effect the oscillation of the air near pressure nodes. i.e. if there is resistance to the air oscillation, that will also damp the sound, making increased resistance or back pressure for the player. However considering the "golf ball" effect (- the dimples making the golf ball travel with less resistance) and rough shark skin effect (providing less resistance against the sea) the smoothness of the Teflon may well have the opposite effect from what we imagine.

So we are left with other effects caused by these inserts. They do interfere with the general conical shape of the bore, and that may well affect pitch of some or all notes. I have no expertise here, especially for conical bores..

There are others here with a lot more acoustic science expertise than myself, whose comments I would welcome.
 
#34 ·
All well and good and in the same la la land as resonator effects et al.

As to the technical details of how such an insert works and what its effect will be with absolute precision, I don't believe ANYONE can provide that exactly. Surely there are many who can come up with a credible approximation based upon what is known; I'm not one of those.

As outlined above- I only know that the modification as described brought the upper part of the second octave (and the palm notes) down into tune with the rest of the horn and made it more playable for me- the guy who plays this particular horn. I noted (and having just played it approximately 4 minutes ago this is a relatively current assessment) no adverse effects.

I by no stretch whatsoever recommend it as an "everybody ought to do this" deal; worked for me, (old Selmer Soloist C*, VD 3), may not work at all for another. Darned if I know why.

For sure, byond doubt, absolutely without a question; a teflon (or other relatively durable smooth coating) on the inside of a tubular cork insert in the neck keeps the cork from slowly but surely disintegrating if one, as I do, runs a swab through the neck prior to putting it away in the case upon each use. There's also a lot less purchase for "gunk" even if one doesn't swab the neck regularly.

Agree the wall effects from rough interior surfaces may actually enhance rather than degrade airflow- but the overall merits (if any) of a smooth or rough surface inside the horn at a given location are not known to me.
 
#35 ·
I think we may be in total agreement.

I was not casting aspersions on whether the fix worked. I was challenging some of the concepts of saxophone acoustics that have crept into this thread, in order to undermine the spread and reinforcement of possibly/probably incorrect concepts.