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Saxophone mouthpiece study

kymarto

Content Expert/Moderator
Staff member
CE/Moderator
#81
I'm sure the half angle would be useful, if not indispensable, in determining the missing volume. I the angle is not constant, then it becomes an interesting question of which angle and how much and when which angle applies.

Then there is the tricky questions of what constitutes the effective volume, which will depends on reed displacement which varies with reed strength and embouchure. Then there are the reed mechanics, which tend to lower pitch, and ambient temperature and gas composition, all three of which affect pitch independent of mpc volume, and the last two of which are often present as a gradient within the air column.

The point being that if you try to quantify things, there is a lot to consider in trying to come up with operative numbers that will predict empirical results. But you will certainly learn something, at worst that your work is inadequate to come up with good results.
 

jbtsax

Distinguished Member
Distinguished Member
#82
It sounds as if you are dismissing out of hand the work done by Benade and Gebler to find the effective volume of a saxophone mouthpiece by the drop in pitch it produces on a cylindrical tube with a known resonance frequency when placed the same distance on the tube's corked end as it goes onto the instrument's neck. Benade states that his figures for equivalent volume are slightly larger than those found by Nederveen and Backus using laboratory excitation devices, but that there is no real discrepancy since his tests using actual playing conditions measured more than one variable involving the reed.

If you will note the chart on page 466, you will see it shows very consistent measurements of "effective mouthpiece volume" done with two different players in 3 separate trials. What's more the "effective volume" measurements are quite constant over much of the instrument's playing range. I am comfortable with Benade's method which I have previously used, and will continue to use throughout my tests and measurements. As far as the other variables you mentioned, playing the cylindrical tube(s) and the saxophone(s) in the same time frame, in the same room, using the same mouthpiece, reed, and embouchure should work just fine to make the comparisons required for the study.

I will post more when I have received a response from Jer-Ming Chen.
 

kymarto

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Staff member
CE/Moderator
#83
I look forward to updates. Whatever happened to your findings that (IIRC) your measured volume was 30 odd percent too small?
 

jbtsax

Distinguished Member
Distinguished Member
#84
I look forward to updates. Whatever happened to your findings that (IIRC) your measured volume was 30 odd percent too small?
I believe you are referring to the paper I have attached below in which the "equivalent volume" of an alto saxophone was found to be 33% greater than its measured volume. That result is quite consistent to Benade and Gebler's findings in the chart on p. 466 FMA where the average seems to be in the vicinity of 30%.
 

Attachments

kymarto

Content Expert/Moderator
Staff member
CE/Moderator
#85
Ah yes...I'm having trouble envisioning the reed displacement at the tip being 1/3 the "hard" volume of the interior of the mpc to the neck insertion point. I politely suggest that some of the other factors I mentioned might have something to do with that :)
 

jbtsax

Distinguished Member
Distinguished Member
#86
Benade refers to the "equivalent volume" under playing conditions as including the elasticity of the reed as well as an oscillatory effect discovered by Helmholtz which I do not understand. Perhaps you know more about the "oscillatory effect" as it involves the mouthpiece and reed and can explain it to me. Benade goes on to say that his studies with Gebler confirmed that the cavity within an active reed as being equivalent to a fixed volume whose size is controllable to some extent by the player as he makes changes in blowing pressure and embouchure tension.

Their study entitled "Reed Cavity and Neck Proportions in Conical Woodwinds" is unpublished. A 14 page copy is contained in the Musical Instrument Acoustics Library (MARL) at Stanford University. It is likely that this obscure study would shed some light on what I am trying to do. I am in the process of finding out who to contact to see if a copy can be made available of that work.
 

kymarto

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Staff member
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#87
Benade refers to the "equivalent volume" under playing conditions as including the elasticity of the reed as well as an oscillatory effect discovered by Helmholtz which I do not understand. Perhaps you know more about the "oscillatory effect" as it involves the mouthpiece and reed and can explain it to me. Benade goes on to say that his studies with Gebler confirmed that the cavity within an active reed as being equivalent to a fixed volume whose size is controllable to some extent by the player as he makes changes in blowing pressure and embouchure tension.

Their study entitled "Reed Cavity and Neck Proportions in Conical Woodwinds" is unpublished. A 14 page copy is contained in the Musical Instrument Acoustics Library (MARL) at Stanford University. It is likely that this obscure study would shed some light on what I am trying to do. I am in the process of finding out who to contact to see if a copy can be made available of that work.
That would be great to see. I don't know about the oscillatory effect, I only know that mechanicall reed effects tend to lower the pitch of the played note below the actual resonant frequency of the system. I really do wonder about temperature and gas composition effects--you are clearly aware how far one has to move the mpc on the neck when temperatures vary. As it gets colder, there is a significant temperature gradient in the tube, as well as a gas composition gradient based mostly on CO2 buildup in the lungs.
 

kymarto

Content Expert/Moderator
Staff member
CE/Moderator
#88
Benade refers to the "equivalent volume" under playing conditions as including the elasticity of the reed as well as an oscillatory effect discovered by Helmholtz which I do not understand. Perhaps you know more about the "oscillatory effect" as it involves the mouthpiece and reed and can explain it to me. Benade goes on to say that his studies with Gebler confirmed that the cavity within an active reed as being equivalent to a fixed volume whose size is controllable to some extent by the player as he makes changes in blowing pressure and embouchure tension.

Their study entitled "Reed Cavity and Neck Proportions in Conical Woodwinds" is unpublished. A 14 page copy is contained in the Musical Instrument Acoustics Library (MARL) at Stanford University. It is likely that this obscure study would shed some light on what I am trying to do. I am in the process of finding out who to contact to see if a copy can be made available of that work.
That would be great to see. I don't know about the oscillatory effect, I only know that mechanicall reed effects tend to lower the pitch of the played note below the actual resonant frequency of the system. I really do wonder about temperature and gas composition effects--you are clearly aware how far one has to move the mpc on the neck when temperatures vary. As it gets colder, there is a significant temperature gradient in the tube, as well as a gas composition gradient based mostly on CO2 buildup in the lungs.
 

jbtsax

Distinguished Member
Distinguished Member
#89
You can say that again. :)

Seriously, I have contacted the Stanford Library Collections Department and have placed an order for a copy of the unpublished Benade/Gebler paper. They can't (or won't) do a pdf file so they will have to mail a photocopies. More when they arrive. . .
 
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