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How damaging to a horns sound .. tone.. would buffing be .. ?

That is .. I see many horns that are shunned because they are "re-lacquers" that have, perhaps , been buffed. I can see the result as damaged engraving on the bell but ... the tone .. sound ?

...there seem to be some bargains on some horns that are buffed

thanks
Fras
 

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It seems to me that from the lacquer condition there could be conclusions drawn about the life and care a horn has had:

1/ original and unworn laq = very little use
2/ original and worn laquer = well used
or
3/ re-laq = could have have "gone around the clock" more than once, to borrow a motoring term.

Given that there is a lot of stretching of the brass sheet going on in the manufacturing process the wall thickness is likely to be far from uniform or consistent from one horn to another let alone between manufacturers. Such that i can't see how the relatively small amount of brass removed even during buffing could have an effect of the tone. I guess manufacturers must test different brass thicknesses and with different mechanical properties for tone and response, now wouldn't that be illuminating to see those results!

For interest there are videos of the manufacturing process at the links below:

http://www.schreiber-keilwerth.com/englisch/general/factory_tour_jk.htm

http://www.webcastgroup.com/webcast/window_new/frameset.asp?WebcastID=2762&n=&e2=&c=&nf=&nl=&r=&i=

There is a better Keilworth video around as well but i coundn't find it.
 

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Where buffing does do a lot of damage is when tone holes edges are carelessly buffed away, making an undulating edge.

There are factory tours for Yamaha and Keilworth at http://www.saxshop.nl/
Click on kthe tab "saxofonwinkel" - "Movies"
The Yamaha one is also at http://www.yamaha.com/yamahavgn/CDA.../0,6383,CNTID%253D32071%2526CTID%253D,00.html


Also Jinyin at http://www.jinyinusa.com/SaxWorks.htm
Selmer at http://www.webcastgroup.com/webcast/window_new/frameset.asp?WebcastID=2762&n=&e2=&c=&nf=&nl=&r=&i=

Stills for Yanagisawa at
http://www.cybersax.com/graphics/tech/YaniTour/YaniTour_Page_1.html
or
http://www.yanagisawasax.co.jp/en/about/assemble/
 

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Forum Contributor 2007-2012, Distinguished SOTW Te
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I'm not sold that buffing has any affect on sound. What it affects is fit of the keys and levelness of toneholes, which directly affects how the pads seal and how it feels under the fingers. BUT, with a good overhaul, both of these problems can be fixed.

I agree with what Gordon and Paulio said.

I also have bought relacquers for my own personal use knowing that with a little elbow grease I would have myself a horn that plays just as well to my ears for way less cash. I try to keep away from them for horns I am going to sell, but that is just responding to the market vs. me believing an overhauled relacquer is a substandard horn, because I definitely don't believe that.
 

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As long as the buffing doesn't draw the copper content out of the brass it'll sound fine! :D ;) :sign5: :notworth: :walk:

Seriously, buffing's physical damage should be more of a concern than what the tonal difference may or may not be.
 

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I just picked up a dirt cheap conn 10m from 1935 that has obviously been relacquered and buffed. It needs some work but the notes that play sound great.

Anything I should look for to see if the RTH's have been buffed?
 

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If it plays great then just play it! Worry not because if the RTH's were damaged from over buffing then it would surely have many leaks and not play very well.

Great horns BTW!
 

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The horn has not been played in a long while and needs some TLC. The notes that did speak though sounded great.
 

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Heavy buffing shows most prominently on anything that sticks out: like the edges of key post feet, edges of ribs, etc. There is a possibility that buffing could affect the sound if more than about 1/4 the thickness of the metal of the body tube was taken away at certain critical points.

Toby
 

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Toby, I am interested in what you have to say on this matter. You part you say about certain critical points- are you speaking about nodal points? In that case, would only certain notes be affected, depending on where the metal is thinned? And would the metal have to be thinned all the way around the body at that point, or only one spot? And what would the (possible!) effect be on the tone? What difference might thinner metal make that would cause the tone to be different? What about that layer of static air in the bore, does that do anything to separate the vibrating column from the body of the horn, acoustically?

Toby, you know more about acoustics that most, so I beg your pardon if these questions don't quite apply, but perhaps you can see what I am getting at and educate me. I know a bit about the acoustics of woodwind instruments, but not as much as I'd like to. Thanks in advance for what could be a long post!
 

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abadcliche said:
Toby, I am interested in what you have to say on this matter. You part you say about certain critical points- are you speaking about nodal points? In that case, would only certain notes be affected, depending on where the metal is thinned? And would the metal have to be thinned all the way around the body at that point, or only one spot? And what would the (possible!) effect be on the tone? What difference might thinner metal make that would cause the tone to be different? What about that layer of static air in the bore, does that do anything to separate the vibrating column from the body of the horn, acoustically?

Toby, you know more about acoustics that most, so I beg your pardon if these questions don't quite apply, but perhaps you can see what I am getting at and educate me. I know a bit about the acoustics of woodwind instruments, but not as much as I'd like to. Thanks in advance for what could be a long post!
Here is basically how it works: The body of a woodwind instrument should not vibrate, unlike the body of a guitar or a violin, for instance. Those latter instruments would sound pretty poor if it were only the strings vibrating, so they couple a larger vibrating mass (in this case the wooden body) to an exciter (a string) to move a lot of air and radiate sound. They are very much like speakers in that sense--the moving coil (analogous to the string) wouldn't output much sound if it were just moving by itself. By attaching a cone, that moving coil can move a lot of air.

If you know speakers, you know that the holy grail of cone composition is a material that is both rigid and very light. It needs the rigidity to overcome the resistance of moving a lot of air without flexing and thus losing energy to heat. It needs the lightness for good transient response--so that it can be accelerated and decelerated quickly, in order that the moving coil can faithfully respond to the electrical impulses governing its movement.

There is a critical difference in a wind instrument--the body does not mediate the coupling of the exciter (a reed of some kind) with a large body of air. Instead the air is shaped in a column in such a way that the small movement of air through the reed is effectively magnified as a few air molecules bump against a few more air molecules, which are forced to focus their energy by the walls of the instrument in such a way that they bump against even more molecules...

The only thing that the body should do is to shape the air column effectively for that task, without taking any energy away from the moving air--letting all the energy be transferred to other air molecules. Therefore the walls should be as smooth as possible, to minimize the boundary effect whereby air molecules near walls lose energy to friction. Also the walls should not flex at all, as this means that the air molecules are transferring energy to the walls instead of other air molecules (which are much lighter and therefore much more efficient at radiating sound than the molecules of metal or wood). Also, when the walls flex it has the effect of changing the bore--effectively widening it at the point of flexure. This can be even more destructive to good sound production than the loss of energy, as it can alter the bore shape necessary for the correct relation of the partials.

So how do walls flex? They can only flex significantly if they have a resonant frequency that matches one of the frequencies of the air column (the note being played or one of its partials). If there is a match, a resonance is set up in the walls in a way that the movements are additive. Think about bouncing on a trampoline--if you want to bounce higher, you have to make sure that you hit the mat when it is at its lowest point--stretching it further downward when it is as low as it can go given the energy it already has. If you are going down as the mat is coming up the energies will cancel destructively (possibly to your neck and spine) as both moving objects come to a screeching halt.

If a resonance of the walls does not match a resonance of the air column, you will never get the walls to vibrate significantly, because the energy of the waves of the air column will never be in sync with the waves in the metal, so that no oscillation can build up.

Of course metal and wood have lots and lots of resonances, so how do we make sure that none of them can possibly match the frequency of the air column? We have to make sure that the lowest resonant frequency of the metal (or wood or plastic) is well above the highest potential musical note of the instrument (or the highest partial where there is significant energy). Making the material thick is one way to do this--the thicker the material the higher the resonant frequency. Another way to do this is to curve the material--the tighter the curve, the higher the resonant frequency (think of musical saws or flextones). A tube of circular cross-section has very high resonant frequencies--and this is exactly the cross-sectional shape of woodwind instruments (for this good reason).

Ah...now you are saying that tubular bells and wind chimes are circular in this sense and play nice musical tones. However this is a different beast--this is an elliptical deformation caused by striking one part of the circle only--but the waves of the air column exert exactly the same pressure all the way around the tube--meaning that the whole tube has to expand like a balloon to flex. It doesn't...very much: not enough to be significant musically or acoustically. Circular tubes of even rather thin material have very high resonant frequencies, well above anything that the instrument can play.

Now comes the fly in the ointment: when the tube isn't circular, the resonances drop dramatically--and this happens in musical instruments around tone holes--where part of the circle is missing. There is evidence that areas around tone holes can vibrate in sympathy with notes being played in some cases: Benade says that there are certain acoustic phenomena in very-thin-walled flutes that can only be attributed to this. AFAIK there have not been any experiments with saxes in this regard, but saxes do have a rather low material thickness/circumference ratio (especially lower down) which might be approaching a point where the resonant frequencies drop sufficiently to couple with playing frequencies--especially around tone holes.

This is what I was referring to when I mentioned "critical points". I'm only guessing, but it seems a reasonable assumption that heavy buffing around tone holes where the body circumference is great could lower the highest wall resonance to allow body flexing--destroying the bore profile and wasting energy. Certainly at a certain thickness this would happen, even with a circular cross-section. I don't think, though, that the parameters have ever been worked out, and I don't know how much metal is taken off in heavy buffing. So I don't know if buffing in the real world would really be significant.

HTH,

Toby
 

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abadcliche said:
Toby, I am interested in what you have to say on this matter. You part you say about certain critical points- are you speaking about nodal points? In that case, would only certain notes be affected, depending on where the metal is thinned? And would the metal have to be thinned all the way around the body at that point, or only one spot? And what would the (possible!) effect be on the tone? What difference might thinner metal make that would cause the tone to be different? What about that layer of static air in the bore, does that do anything to separate the vibrating column from the body of the horn, acoustically?

Toby, you know more about acoustics that most, so I beg your pardon if these questions don't quite apply, but perhaps you can see what I am getting at and educate me. I know a bit about the acoustics of woodwind instruments, but not as much as I'd like to. Thanks in advance for what could be a long post!
Here is basically how it works: The body of a woodwind instrument should not vibrate, unlike the body of a guitar or a violin, for instance. Those latter instruments would sound pretty poor if it were only the strings vibrating, so they couple a larger vibrating mass (in this case the wooden body) to an exciter (a string) to move a lot of air and radiate sound. They are very much like speakers in that sense--the moving coil (analogous to the string) wouldn't output much sound if it were just moving by itself. By attaching a cone, that moving coil can move a lot of air.

If you know speakers, you know that the holy grail of cone composition is a material that is both rigid and very light. It needs the rigidity to overcome the resistance of moving a lot of air without flexing and thus losing energy to heat. It needs the lightness for good transient response--so that it can be accelerated and decelerated quickly, faithfully following the movement of the coil with as little inertial resistance as possible.

There is a critical difference in a wind instrument--the body does not mediate the coupling of the exciter (a reed of some kind) with a large body of air. Instead the air is shaped in a column in such a way that the small movement of air through the reed is effectively magnified as a few air molecules bump against a few more air molecules, which are forced to focus their energy by the walls of the instrument in such a way that they bump against even more molecules...

The only thing that the body should do is to shape the air column effectively for that task, without taking any energy away from the moving air--letting all the energy be transferred to other air molecules. Therefore the walls should be as smooth as possible, to minimize the boundary effect whereby air molecules near walls lose energy to friction. Also the walls should not flex at all, as this means that the air molecules are transferring energy to the walls instead of other air molecules (which are much lighter and therefore much more efficient at making sound than the molecules of metal or wood). Also, when the walls flex it has the effect of changing the bore--effectively widening it at the point of flexure. This can be even more destructive to good sound production than the loss of energy, as it can destroy the bore shape necessary for the ideal transmission of energy (and the relation of the partials, which are determined by the shape of the bore).

So how do walls flex? They can only flex significantly if they have a resonant frequency that matches one of the frequencies of the air column (the note being played or one of its partials). If there is a match, a resonance is set up in the walls in a way that the movements are additive. Think about bouncing on a trampoline--if you want to bounce higher, you have to make sure that you hit the mat when it is at its lowest point--stretching it further downward when it is as low as it can go given the energy it already has. If you are going down as the mat is coming up the energies will cancel destructively (possibly to your neck and spine) as both moving objects come to a screeching halt.

If a resonance of the walls does not match a resonance of the air column, you will never get the walls to vibrate significantly, because the energy of the waves of the air column will never be in sync with the waves in the metal, so that no oscillation can build up.

Of course metal and wood have lots and lots of resonances, so how do we make sure that none of them can possibly match the frequency of the air column? We have to make sure that the lowest resonant frequency of the metal (or wood or plastic) is well above the highest potential musical note of the instrument (or the highest partial where there is significant energy). Making the material thick is one way to do this--the thicker the material the higher the resonant frequency. Another way to do this is to curve the material--the tighter the curve, the higher the resonant frequency (think of musical saws or flextones). A tube of circular cross-section has very high resonant frequencies--and this is exactly the cross-sectional shape of woodwind instruments (for this good reason).

Ah...now you are saying that tubular bells and wind chimes are circular in this sense and play nice musical tones. However this is a different beast--this is an elliptical deformation caused by striking one part of the circle only--but the waves of the air column exert exactly the same pressure all the way around the tube--meaning that the whole tube has to expand like a balloon to flex. It doesn't...very much: not enough to be significant musically or acoustically. Circular tubes of even rather thin material have very high resonant frequencies, well above anything that the instrument can play. It isn't by coincidence that the main vibrating parts of drums and guitars and viols are flat or nearly so.

Which leads to the fly in the ointment: when the tube isn't circular, the resonances drop dramatically--and this happens in musical instruments around tone holes--where part of the circle is missing. There is evidence that areas around tone holes can vibrate in sympathy with notes being played in some cases: Benade says that there are certain acoustic phenomena in very-thin-walled flutes that can only be attributed to this. AFAIK there have not been any experiments with saxes in this regard, but saxes do have a rather low material thickness/circumference ratio (especially lower down) which might be approaching a point where the resonant frequencies drop sufficiently to couple with playing frequencies--especially around tone holes.

This is what I was referring to when I mentioned "critical points". I'm only guessing, but it seems a reasonable assumption that heavy buffing around tone holes where the body circumference is great could lower the highest wall resonance to allow body flexing--destroying the bore profile and wasting energy. Certainly at a certain thickness this would happen, even with a circular cross-section. I don't think, though, that the parameters have ever been worked out, and I don't know how much metal is taken off in heavy buffing. So I don't know if buffing in the real world would really be significant.

HTH,

Toby
 

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Thanks Toby. I appreciated that snipet of acoustic science, expressed without the usual jargon overload that acousticians use.
 

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mods--

Somehow I managed to post that lengthy message twice, and don't see a way to delete one. Can you do this for me?

TIA

Toby
 

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Gordon (NZ) said:
Thanks Toby. I appreciated that snipet of acoustic science, expressed without the usual jargon overload that acousticians use.
Yes. Well written. Thanks Toby! ;)

Yes. Well written. Thanks Toby! ;)

:D
 

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Ok! But a delaquered horn looks so cool... ::cool:

Stan
 

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Stan said:
Ok! But a delaquered horn looks so cool... ::cool:

Stan
If you're doing it because you like the way it looks then go for it.

If you're doing it because you're looking for a different sound then, practice more and think less! ;) :shock: :D
 

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Stan said:
Ok! But a delaquered horn looks so cool... ::cool:

Stan
One can delacquer a horn without buffing. it is only if you want to relacquer it and have it 'shiny' that some buffing is necessary, although this can be done by means of a hand polish. The labor is higher however.

It is difficult to get a horn uniformly shiny all over (including around the base of toneholes and posts) on a powered buffing wheel without a few spots getting a bit thinner. It can be done, but generally only with several different size wheels running at different speeds for the different details. Most shops that I have seen just have one big soft wheel and just lean on it...
 

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Toby, that may be the single-most useful bit of information I have ever read on here. I try and explain these concepts in terms of acoustics all the time, like why microscopic changes at the mouthpiece/reed level will have an exponentially greater influence on the saxophone sound as giant dents in the bell or bow. People ask me if engraving changes the sound, and of course it doesn't, but it's hard to put it in laymen's terms as you have above. Another note about buffing is that it can potentially heat up and stress the brass in ways that alter its consistency.
 
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