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 Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-08 20:49

This might have been a tangent off the discussion about tone in the thread about Brio reeds. But I didn't want to risk hijacking that thread. Depending on the actual state of knowledge, this may be a rich area for learning, or a complete crash and burn.

A sounding clarinet's air column vibrates in multiple modes at once - primarily over its full length (the fundamental), in thirds (3rd harmonic - the 12ths), in fifths, sevenths, etc.. The player can manipulate the strength of the harmonics through technique and equipment can tend to favor specific harmonic ranges, and in either case, the tone quality is affected.

What is the correspondence of the reed's vibrating mode to those of the air column? Assuming (as I do intuitively and from what little literature I've run across) that the reed in some way synchronizes with the air, does it react to the air column's vibrations that are determined by the instrument's length and venting, or is it a provocateur that causes the air column to split into harmonics. Obviously, when we open a register vent, the instrument is controlling the pitch. When we play "bugle calls," whether on a clarinet or on a real bugle, the reed's (lips') vibrating mode is controlling things. What about the harmonic content in normal tone production at any given pitch level? From what I *have* read, the frequencies aren't identical. But is the harmonic *distribution* the same between reed and air column?

Assuming the reed's harmonic mode is as complex as the air column's, where do the harmonic divisions occur in the reed? Does the spine vibrate as a single unit (producing the fundamental) while regions of varying stiffness as the reed thins toward the edges and tip vibrate at increasingly higher harmonic frequencies? Or does the division occur mostly along the vamp's length.

I would imagine the physical distribution of harmonic multiples over the surface or even the volume of the reed would dictate how the reed needs to be shaped to encourage or discourage the generation of specific harmonic ranges. As players most of us go by empirical experience - ours or others' - and there are diagrams in every book chapter and periodical article about reed adjustment all of which look like the diagrams that identify the different cuts of meat from a steer or hog. Scrape here and the tone becomes "darker" or "brighter" or more resistant or more responsive, etc.. Most if not all of the instructions and teaching about reed making or adjustment are grounded in "I believe", or "I feel", or "In my experience" - all based on "if you take cane out here, the result will be...".

But in the Brio thread much was said about the actual harmonic content players strive to produce. Is there meaningful, physics/(acoustics)-based mapping of a reed's vibrations that could guide players to more reliable, less guess-y adjustments?

It may be that this is a more or less moot issue, that those diagrams that we already have are enough to accomplish the purpose. Are reed designers (Bob? Brad? any input?) also guided by those meat diagrams plus trial and error, or do you work with the kind of information I'm describing?

I apologize for my long-windedness. I'm struggling a little to formulate the question itself so some of the verbiage is my own attempt to clarify the problem in my own mind.

Karl

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 Re: Harmonic division of the reed - Brio tangent
Author: Paul Aviles 
Date:   2020-11-08 22:23

If I may, I would like to address the "I believe...."


In my experience (no irony intended) the reed needs to interact with the mouthpiece to achieve all the acoustic end results of which we speak and that adds all the other variables such as overall footprint of the window, length, width, shape, thickness of rails........then facing variables, etc etc.


Also print being what it is, I often get chided for NOT putting in the qualifier "I think....." whenever I leave it out of a post. I think most readers want to read a post as if it is gospel without the qualifier, or rather, take offense that that was the intent.


Since much of what clarinet craft is as much art as science, no one writing a treatise on any one complex aspect wants to be mistaken for trying to present the "final word "



...........I believe



...................Paul Aviles

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 Re: Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-08 23:25

Paul Aviles wrote:

> In my experience (no irony intended) the reed needs to interact
> with the mouthpiece to achieve all the acoustic end results of
> which we speak and that adds all the other variables such as
> overall footprint of the window, length, width, shape,
> thickness of rails........then facing variables, etc etc.
>
Well, I suppose that seems obvious. But it isn't really directly related to my question. How do various mouthpiece parameters affect the reed's vibrations (other than potentially just cutting them off in one way or another)? What *are* the results in terms of increased or damped harmonic content and where on the reed do the effects occur?
>
> Also print being what it is, I often get chided for NOT putting
> in the qualifier "I think....." whenever I leave it out of a
> post. I think most readers want to read a post as if it is
> gospel without the qualifier, or rather, take offense that that
> was the intent.
>
The problem isn't leaving out "I think," it's saying "it is" or, more strongly, "it must be" when others' experience tells them something different. The 2nd sentence confuses me - I don't really understand what you mean - but it also isn't directly related to my question, which tries to put aside or by-pass the kind of "do this to get that" processes that we all rely on to get through every day.

> Since much of what clarinet craft is as much art as science, no
> one writing a treatise on any one complex aspect wants to be
> mistaken for trying to present the "final word "
>
I'm denying the art. I want to know what the state of the science is. To the extent they're separable, it ought to be possible to discuss one without repudiating the other.

"I believe" and "I think" are subjective reactions. They are absolutely valid as day-to-day guidance for day-to-day activities. The kind of experience-based decisions we make like where to scrape to free up the response of a stuffy reed are useful and don't need elaborate explanations from physical science. For one thing, we often don't have time to reason through an explanation. We just need a result. Now. So, if we think we know what to do, we just do it.

But if there is observable, quantifiable underlying science available to support - or contradict - those belief-based daily actions, I think it's worth while to look for it. Not to solve a problem that needs an immediate solution, but to build the knowledge on which we may base future understandings and modify - or keep - what we currently think is true.

What, in general, is my reed doing while I'm playing low chalumeau notes or notes higher in the compass? What is it doing when I play very softly? Very loudly? When I get a squeak? How does the reed behave differently when the sound changes over a register break from when we are able to cross the same break seamlessly, with no change in tone? We all have experience-based ways to make chalumeau notes sound richer, altissimo notes less strident, squeaks less likely, and register changes smooth. I'm asking what, based on harmonic divisions of the reed's vibration, contributes to the sound quality and its variations, to unintended harmonic notes (squeaks), to register crossings that sound like two different instruments are at work. What's going on at the level of reed vibration and how can the reed's physical properties - mostly its dimensions - contribute to changing any of this, but particularly in terms of tone "color"?

I suspect some of the information I'm looking for is available in the writings of Arthur Benade and others, but I find that the nitty-gritty explanations tend to involve math that I can't follow. I can wish I had paid more attention in my high school and college calc classes, but that's now water under the bridge. I'm not denigrating "I think" or "I believe," but the physical world exists, and I'm simply asking what anyone can say about it.

Karl

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 Re: Harmonic division of the reed - Brio tangent
Author: Paul Aviles 
Date:   2020-11-09 01:41

Firstly these questions may be only answerable by Brad Behn, if there are quantifiable answers.




What I do KNOW is that the reed is merely an actuator. The vibrations that create the sound we hear are in the air column within (and slightly beyond for the lowest notes) the confines of the instrument. So what we are talking about is already one step removed from the primary source.



The other thing that I KNOW is that musical vibrations are STANDING WAVES. It is not a simple matter of something just vibrating up and down regularly across the full length. Note videos here:


https://www.youtube.com/watch?v=MoUQdcLmz5g

https://www.youtube.com/watch?v=kpoanOlb3-w


I would ASSUME (I guess) that the clarinet reed in action would behave similarly (and with similar unpredictable waves across its width and length).



And if there were precise mathematical relationships to achieve exactly the same results every time for cymbals (for example), then every company's cymbals would be capable of sounding like Zildjians (subtle endorsement).




....................Paul Aviles



Post Edited (2020-11-09 13:58)

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 Re: Harmonic division of the reed - Brio tangent
Author: Matt74 
Date:   2020-11-09 08:39

I’ve wondered about the same thing.

Best guess:

First the overall frequency, then the reed itself.

Overall: The reed produces the vibration in the air column, but the column partially controls the reed. IDK if there is a 1 to 1 correspondence of the reed frequency and the air column frequency, but it’s reasonable to assume there is some relation, it certainly feels like it. If the reed is vibrating “close enough” to the necessary frequency to create a given note or partial, once the column is in motion it brings the reed into the correct frequency by sympathy. If they are completely at odds you’d get a squeak or nothing. If they are fighting you get poor response.

Reed itself: Think about strings first. Thick strings are less flexible than thin ones so, when sounding a note they have fewer partials present. They sound dark or dull. Thin ones are flexible so they produce a lot of overtones and sound bright. You can produce better overtones by harmonics on thin strings than thick ones (although higher tension also makes it harder). Likewise, the thick part of the reed resists change and resists higher partials, while the thin part is more flexible. Also the longest part of the reed produces lower frequencies, because it’s long, while the shorter part produces higher frequencies - even though the whole reed is always moving.

So, it seems reasonable to assume that, for the most part, lower air column frequencies are created by, and in turn affect the whole vamp, while higher frequencies interact more with the tip. This seems to agree with experience. It also seems reasonable that certain partials interact with certain places on the reed more than others (depending on mouthpiece and cut). Hence, those reed adjustment charts.

However it seems unlikely that overtones in the reed play a large role in controlling the HEARD overtones of the column, or “overblowing”. 1. Because we don’t move our lips back and forth on the reed all the time - even if it’s possible to do it when you try. 2. And because the column has so much more force than the reed. For example clarinet reeds and saxophone reeds are more or less interchangeable if they fit, However a clarinet will never produce the odd harmonics no matter what you do to the reed. Also the normal way of producing harmonics is through voicing, register keys, or odd fingerings. So the column is clearly controlling “overblowing”, not the reed.

Nevertheless, the column “wants” the reed to do something, and the more easily the reed complies the more responsive the instrument is. Effectively, if the reed/mouthpiece combo are fighting with the air column it’s harder to overblow.

That said, the reed cut and strength does seem to have a profound effect on the “unheard” partials, and thus the timbre. And, it seems that some cuts make it easier to overblow, not by controlling the column, but by matching the tendencies of the column. My guess is that the nodes of the reed move along the reed in response to the player/air column, and are not in one specific place, as the way reed as a whole changes its vibration and interacts with the mouthpiece.

- Matthew Simington


Post Edited (2020-11-09 09:04)

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 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-10 12:29

Disclaimer: All of the below are simply my opinions, guesses, perceptions, etc.

KDK wrote: "What is the correspondence of the reed's vibrating mode to those of the air column?" I had some trouble with that question, so I changed it slightly to: "What is the correlation of the reed's vibrating mode to those of the air column?" Well, because the reed can only initiate a vibrating column of air on the upward bend of the reed, at that point in time, the correlation is the same. However, this sameness can be changed by making adjustments to the reed. The tone may change, however, I still maintain that the correlation of the two is still the same. Even though an adjustment of the reed may change a specific harmonic level, it is still the upward swing of the reed which sets the column of air vibrating. It is in the upward swing that the reed acts as the "provocateur that causes the air column to split into harmonics."

Now, what happens when the vibrating air column causes the reed to swing downward? At this point in time, the reed simply "reacts to the air column's vibrations that are determined by the instrument's length and venting."

So, from my point of view, the reed has a two fold function: 1) as a provocateur and 2) as a passive reactor.

Obviously, any change or adjustment to a reed is going to change it's mode of operation. The easiest way that I know of to get the precise tone that you are striving for is to have a look at the clarinet's tone on an audio spectrum analyzer. Any change a player makes to his or her reed is going to change the strength of various harmonics, or, possibly, even a specific harmonic output.

All of the above may be totally erroneous, however, that how I analyze it.

p.s. The bold was included to denote KDK's wording.



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 Re: Harmonic division of the reed - Brio tangent
Author: Luuk 2017
Date:   2020-11-10 13:41

This is basic physics. Any mass-spring system will develop a periodic movement when fed with energy. The key question is which frequency will be developed, and that depends on, for instance, spring characteristics, tension, dampening, mass etc.

Musical instruments are designed in such a way that a merely random input of energy (noise) is used to develop the desired frequencies.

Violin: the microscopic action of the bow on the string is noisy (just rubbing sticky hairs against the string), but string length, tension and mass quickly promote a series of discrete frequencies. The same with trumpet: the buzzing lips produce a broad spectrum of frequencies, but the tube only resonates with certain frequencies. Thus, the input energy is used to create a discrete spectrum of sound.

Radio receivers work the same way: noisy signal from an antenna is fed to a circuit which resonates at a certain frequency. This resonating frequency can be tuned to a desired station. Another example: the collapsing Tacoma Narrows Bridge (look it up on YouTube!). This bridge fails because it develops a resonance under the merely random energy fed by the blowing wind.

The volume of air inside tube of the clarinet only resonates at certain frequencies. The source of sound energy, the flapping reed, is acoustically coupled to the tube. The two parts influence each other. The tube is very efficient in putting all energy in a discrete spectrum. This is the sound that will be heard.
In response of the waves developed in the tube, the reed will move 'in tune'. Not because the spectrum as developed by the tube fits the reed, but because it is forced to do so by the standing wave. Remember, almost all energy is put into that standing wave. This 'kicks' the reed every time it reaches it. Since the reed is small and light, it follows the tube.

Of course, reed mass or strength will have some influence on the spectrum in the tube. The reed is small, but not neglectable. This is the essence of acoustical coupling: both parts influence each other. However, some factors (tube length) are much more important than others (reed mass).

For a thorough but light introduction: see Arthur Benade, Fundamentals of Musical Acoustics.

Regards,

Luuk
Philips Symphonic Band
The Netherlands

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 Re: Harmonic division of the reed - Brio tangent
Author: Burt 
Date:   2020-11-10 18:10

I believe that Luuk has summarized the matter accurately and completely.
Burt

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 Re: Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-10 19:19

Thanks, Luuk. I think I understood most of this intuitively (or based on the physics and acoustics I remember from school or I've been able to pick up without reference to advanced math). You've added clarity, especially as concerns the match between the reed and the vibrating air column.

My main remaining question has to do with the physical mapping of the vibrations. Obviously, i think, the whole reed must vibrate at the fundamental frequency. Where do the nodes occur physically *in the reed*? In the standard drawing of a vibrating string or air column, the divisions - the nodes - occur at discrete points along the full length, so, for example, the entire A string vibrates nominally at 440 Hz, but areas are also visible (at least in the drawings) in fractional portions along that length that are vibrating at 880 Hz, 1320 Hz, 1760 Hz, 2200 Hz, etc.. The string, if this isn't an illustrator's oversimplification, divides along its length.

The reed differs from a string (or even, I suspect the standing wave inside the tube of a wind instrument) in that it has a relatively larger width in proportion to its length, and the thickness of the reed varies in a controlled but substantial way along both the width and the length. How does the reed divide into partials? Along its length (from tip to the bark at the end of the vamp)? Along its width? Both? The crux for me is, what influence do the changes in thickness have on the location of the nodes and the strength of the partials they create?

One of the things I learned early about reed adjustment was not to create "fences," in one clarinetist's description (may have been in an article by Roger Salander decades ago), places where the change is abrupt from scraping too hard in one place. I assume those sudden bumps, whether natural or made-made, tend to compromise the integrity of the longer vibrations. But even a smoothly contoured reed can taper more quickly or more gradually both toward the side rails and toward the butt end. Those meat diagrams basically map where too much cane can cause specific problems - too dull, take out cane here; squeaks, take out a little cane there; too bright, thin this area, etc. I guess I'm interested in why thinning those areas (since you can't add thickness) does what it does. I'm assuming the location of the nodes that produce each harmonic has an important, if not determinative, effect on timbral character and, perhaps, response, that increasing or decreasing flexibility at those locations can encourage or damp the corresponding harmonics.

If one could (maybe this has been done) slow video of a vibrating reed enough to see the various harmonic sub-areas, where would they form? And, I suppose I should also ask, is this too esoteric to matter?

Karl

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 Re: Harmonic division of the reed - Brio tangent
Author: Matt74 
Date:   2020-11-10 22:25

Duplicate.

- Matthew Simington


Post Edited (2020-11-10 22:30)

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 Re: Harmonic division of the reed - Brio tangent
Author: Matt74 
Date:   2020-11-10 22:25
Attachment:  CF195089-B820-482B-AC4F-109D84AED395.png (211k)

I think what you are looking for is called “Vibrational model of single reeds.”

I found this page, which discusses clarinet reeds, but I didn’t see anything about the harmonic nodes of reeds. https://newt.phys.unsw.edu.au/jw/basics.html

This confirms that the reed changes frequency with the column. https://physerver.hamilton.edu/courses/Fall13/Phy175/ClassNotes/Reeds1.html

My guess is that reeds are very “dirty” harmonically, and do not have identifiable nodes, which is why they sound so bad without a resonator.

Here’s a paper about Ullieann pipe reeds. It says the reed does not have harmonic nodes when vibrating freely. http://www.tuftl.tufts.edu/musicengineering/research/uilleann_pipes/uilleann_reed.pdf

It says:

“Looking at the data we can see that the previously mentioned models do a poor job of predicting the motion of the reed. A similarity that does come to the forefront is that our reed is presumably not harmonic in its vibrating nature like all of the previously mentioned models. We can see however that the reed vibrates at harmonic frequencies. Indeed since the instrument in question has a conical bore with a pressure node at one end, and an anti-node at the other theory dictates the reed must vibrate at harmonic frequencies. If we trust the models and assume that the free vibration of the reed is not harmonic then we can say that the air column below the reed dominates the vibrational structure of the reed and forces it to vibrate at harmonic frequencies.”

***So what you really want to know is: “How does the reed vibrate in sympathy with any given partial or note of the clarinet.”***

The paper does confirm that some traditional adjustment practices are effective at producing the desired effects. Obviously, this would be different for single reeds, and single reeds MAY be more harmonic, because they beat against a mouthpiece, not another reed.

More stuff: https://www.semanticscholar.org/paper/Influence-of-strain-gauge-sensors-on-the-behavior-Chatziioannou-Hofmann/0f8f2f524e14edce58b134a1f83a9096bcca27ef

I found pictures there of saxophone reeds vibrating at different column nodes, attached. The description is:

“Figure 4: Decorrelated electronic speckle pattern interferograms of clarinet (left) and saxophone sensor reeds (right) oscillating at their first three resonance frequencies. At every mode the operating deflection shapes are shown from left to right corresponding to no sensor, one sensor and two sensors mounted on the reed. Nodal lines are represented by white regions and moving areas by correlation fringes.”

I think that since the frequency of the reed changes, that the precise “node” of the reed might move depending on how long the column is, but it’s a place to start.

- Matthew Simington


Post Edited (2020-11-10 22:33)

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 Re: Harmonic division of the reed - Brio tangent
Author: Bennett 2017
Date:   2020-11-10 22:53

Consider a flue (not reed) organ pipe. It produces harmonics of its fundamental frequency. If so, where/how are the harmonics produced as there is no reed fluttering this way or that; ditto no string. As I understand it, varying the length/width and material the pipe is made of changes its timbre - and if it has a timbre it has harmonics. The pipe itself may vibrate a bit - if you firmly grab it will its sound change? If its lip is bent a bit this way or that will it sound different or just change pitch?

So if an organ pipe has no moving parts (save air) and produces harmonics why must and/or does a clarinet reed need to move at various frequencies at various spots on the reed? Somewhat a different question than whether the air column in the clarinet and the reed are synchronized with or forcing one another.

I'm confused

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 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-11 00:19

Bennett, I like your flue explanation. Where are the harmonics coming from? Well, actually, I believe you answered it yourself. It's the material the pipe is made of. And, yes, I also believe if you grab the pipe's material, you will change the timbre because the "grabbing" restricts or reduces the vibrations which produce the harmonics and not necessarily at a uniform rate.

While reading your response, a thought occurred to me that never entered my mind before. I kept thinking of how the clarinet reed basically swings back and forth simultaneously with the fundamental tone, but, then, I said to myself, where are the harmonics coming from? And, why do they change when any adjustment is made to the reed? Then it occurred to me that the reed in and of itself is also vibrating independently from the clarinet fundamental tone. And, this independent vibration of the reed itself varies according to the cut and the contour of the reed along with any adjustments that may have been made.

So, in my mind, two separate vibrations are occurring at the same time. Hence, this is why altering the reed through adjustments won't change the fundamental, but, it will definitely change the harmonics due to the separate and independent vibration of the reed itself. At least, that's what makes sense to me.

If this has been mentioned before, my apologies.



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 Re: Harmonic division of the reed - Brio tangent
Author: Luuk 2017
Date:   2020-11-11 19:11

Keep in mind that the reed is small and stiff, and the bore is the major resonator.
The reed should be seen as a so-called perturbation, a secondary influence at best. Frequency spectrum of the clarinet will be 'mostly' (90%? 95%?) determined by the length, diameter and general cilindricity of the bore, and all other factors (chimney lengths, undercutting, bore diameter variations, stiffness of the reed, material used etc. etc.) will give second (third, fourth...) order effects. Nevertheless, they may be audible and relevant.

This paper gives an extended discussion of reed vibrations, and includes lots of pictures of vibrational modes of a reed on a mouthpiece:
https://hal.archives-ouvertes.fr/hal-00668277v1/document. Please note that this describes an experimental set-up, and that in real life the reed will behave different because of the dampening effect of the embouchure (not present in the experiments for this paper), and because the mouthpiece used in this research has a flat lay. But these 'perturbations' may also only be second or lower order. That being said, I expect the so-called transversal modes and the generic modes (see paper) are not present with embouchure added, or at least not wanted (chirping, squeaking).

Regarding the flute: the wind blown over the embouchure hole creates vortices. These vortices initiate vibrations in the pipe of the flute, and again (almost) all energy ends up in the resonant frequencies. Pipe length and basic construction (two-sided open pipe, in the case of a flute) determines the resonance spectrum, where material, subtle changes in diameter etc. have secondary influences, at most. This is why cheap clarinets with worthless reeds still sound as a clarinet, and not as a flute, sax, trumpet etc.

Harmonics do not result from the pipe material, but the precise location and intensity of the harmonics may be influenced in a subtle way by changing the material. 'Timbre' is the perceived quality of the mix of frequencies heard. This mix will be influenced by material, wall thickness etc. but again, only in a subtle way. Nevertheless, subtlety is very important in musical expression!

See f.i. https://link.springer.com/chapter/10.1007/978-3-030-19175-7_9 Effect of Wall Material on Vibration Modes of Wind Instruments: Having in mind theoretical considerations and numerous experimental approaches described in this chapter, we can mention that materials have a limited effect, if any, on the sound of acoustic specimens or experimental musical instruments. On the other hand, the vibration of a wind instrument wall can influence the feeling of a player for various reasons. It is evident that different materials provide very different amounts of damping, and therefore it is also evident that this phenomenon should be taken into consideration.

Regards,

Luuk
Philips Symphonic Band
The Netherlands

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 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-12 01:01

Luuk,

With all due respect, I see two completely contradictory sentences in your last paragraph.

"...we can mention that materials have a limited effect, if any, on the sound of acoustic specimens or experimental musical instruments."

And from the next sentence: "It is evident that different materials provide very different amounts of damping, and therefore it is also evident that this phenomenon should be taken into consideration."

To me, the above two statements about materials are, indeed, contradictory.

You just can't have it both ways.

Is my interpretation wrong?



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 Re: Harmonic division of the reed - Brio tangent
Author: Luuk 2017
Date:   2020-11-12 13:17

Indeed, this seems a contradiction. The text is copied from the abstract of the paper I provided a link to (Bucur V. (2019) Effect of Wall Material on Vibration Modes of Wind Instruments. In: Handbook of Materials for Wind Musical Instruments. Springer, Cham.).

I understand this as 'wall material has a limited effect, but it may not be neglectable'. The same abstract also states At first glance it is evident, for example, that a flute made of wood has a different sound to a flute made of metal alloy.

For me, it all comes down to first vs. higher order effects. A metal flute is thin walled, so I can imagine that the acoustic energy inside the flute can make the wall vibrate. This creates a 'feedback loop', an acoustical coupling. The vibrating wall in turn also influences the waves in the tube. The main principle for creating the sound spectrum will still be the 'open tube' principle of a flute, but this spectrum may be 'deformed' in a subtle way by the wall material used.

Now, a clarinet wall is much thicker and heavier than a flute wall, giving it a high acoustic impedance: it 'resists' being brought into vibration more than a thin metal wall. The acoustic coupling between the air column in the bore and the heavy wall thus will be small. So, I can imagine that wall material will have an even smaller effect on timbre with clarinets than with flutes. But it still may be hearable. However, the smaller the effect, the more it will be subject to discussions (think reed binders, mouthpiece material etc.). In the end, effects will be so small nobody can hear it.

To keep academic discussions focused, 'small' effects often are neglected. Maybe that explains the wording '... has a limited effect, if any...'.

Regards,

Luuk
Philips Symphonic Band
The Netherlands

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 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-13 01:02

Luuk,

Although I enjoy our discussion, it seems to me that I need to stop at this point because, IMO , we have gone way OT. (Reed harmonic operation with specificity towards Brio reeds.)

Hopefully, someone else will continue this discussion...

Cheers!



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 Re: Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-13 05:08

Dan Shusta wrote:

> Luuk,
>
> Although I enjoy our discussion, it seems to me that I need to
> stop at this point because, IMO , we have gone way OT. (Reed
> harmonic operation with specificity towards Brio reeds.)

Dan (and Luuk), just to clarify, since I was the OP for this thread, I included Brio reeds in the subject line only to draw in anyone from seabreeze's original thread about Brios who was interested in the more technical parts of reed vibration and why reed design and shape affect as they do the timbre of the instrument. So, to the extent that the discussion centers on reed harmonic operation, I consider it still very much on topic regardless of having left Brio reeds behind. I think I've learned a great deal through the discussion so far, although it's possible that it has simply run its course at this point.

Thanks to everyone who has contributed.

Karl

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 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-13 07:27

See Karl's link in the next response. I was unable to make a PDF page into a clickable link.

Hopefully, it's not too complex.


Thanks, Karl.



Post Edited (2020-11-13 09:49)

Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-13 07:50

Is this the one?

https://courses.physics.illinois.edu/phys406/sp2017/NSF_REU_Reports/2013_REU/Kristin_Holz_Final_REU_Paper.pdf

Karl



Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-13 09:51

Yes, it is. Thanks, Karl. (I changed mine to refer to yours.)

Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: Tony Pay 2017
Date:   2020-11-16 03:27

Dan Shusta wrote:

>> Yes, it is. Thanks, Karl. (I changed mine to refer to yours.) >>

The link you quoted was:

https://courses.physics.illinois.edu/phys406/sp2017/NSF_REU_Reports/2013_REU/Kristin_Holz_Final_REU_Paper.pdf

Can either of you tell me what is interesting, informative, or even, possibly RIGHT about this paper?

Tony

Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: kdk 2017
Date:   2020-11-16 06:14

Tony Pay wrote:

>
> Can either of you tell me what is interesting, informative, or
> even, possibly RIGHT about this paper?
>
> Tony
Truthfully, Tony, I'm not even sure what a lot of it says. It's a very detailed analysis of the harmonic distribution of one instrument. Getting into the weeds of his analysis would take more careful reading than I have the time to give it, and I'm not sure, having only skimmed it, how much of the detail is within the level of my training.

My interest is in the effect of the distribution of a reed's resistance on the quality and harmonic content of a clarinet tone. I searched (digitally) for any mention of the reed itself and only found a few incidental references to the way the equipment was set up. There's nothing that I can find about the part the reed and, more specifically, its geography/topography, play in generating the harmonic spectrum of an individual clarinet tone.

Karl

Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: Dan Shusta 
Date:   2020-11-16 08:37

Mr. Pay,

Thank you for your response. Having read your musical bio including the fact that you "read Mathematics at Cambridge", it became very clear to me that the moment you wrote "what is...possibly Right about this paper?, it became very clear to me that NOTHING was RIGHT about this paper.

It was clearly far beyond my understanding and I am truly grateful that someone of your caliber took some time to clarify to everyone here that this paper simply has no real, educational value whatsoever.

Please believe me...I'm not trying to insult you, but, rather, I'm thanking you for your time and effort in reviewing the paper that I posted.

So, why did I post it? Because I was hoping that someone with a greater musical and mathematical understanding than I have would find it beneficial. Clearly, per your inquiry, it has little to no value. Thanks, again.


Cheers!



Post Edited (2020-11-16 09:01)

Reply To Message
 
 Re: Harmonic division of the reed - Brio tangent
Author: Tony Pay 2017
Date:   2020-11-18 21:44

I don't really want to engage with the various things that have been said on this topic. Some of them strike me as being helpful, others not so much.

About this 'paper', though, I can be quite clear. It's not defective because of its mathematics, of which actually there is very little. It's defective because it doesn't SAY anything; and what it seems to be trying to say is based on a misconception.

It seems to be trying to assess experimentally the harmonicity of the overtones in a steady clarinet sound of varying pitches. This is a wild goose chase because we already know that steady, driven oscillations are necessarily periodic and therefore harmonic. The measurements therefore say more about defects in the experimental setup than about anything real related to clarinets.

You note that the paper is unpublished. I don't know where it came from, but it strikes me as a graduate student effort that would never pass peer review in any reputable journal of musical acoustics.

The point is implicit in something I wrote here a couple of years ago. This Board is cluttered with so much opinionated noise that the point's subtlety passed by many, though not all, of its readers.

What is the point?

It is that though a reasonably expert player can excite the normal modes of oscillation of a clarinet (the so-called 'bugle calls'), these notes are not harmonics (whole number multiples) of the chalumeau note being fingered.

BUT, when you play the chalumeau note steadily, the overtones ARE whole number multiples of the chalumeau note frequency. What happens in actual clarinet playing does not correspond directly to the normal modes of oscillation of the tube.

It's surprising, perhaps; but there it is. A child looking at an old-fashioned 78rpm gramophone disc is said to have asked, "How do they get a whole orchestra into that wiggly line?"

Michelle Gingras wrote a whole mini-chapter of a book claiming that you could hear these bugle call notes in steady clarinet playing, and it took some effort on my part to persuade her and her publisher that they were in error. And, not because of ME, as I pointed out, but because of Mother Nature herself.

Therefore, I suggest that when Karl writes
Quote:

A sounding clarinet's air column vibrates in multiple modes at once
...he immediately lays himself open to confusion.

A sounding clarinet is a system entire. Everything affects everything else. You can tinker with bits of it, but looking for a simple prediction as to the precise effects of that tinkering is very likely impossible, particularly where the reed is concerned.

By the way, I would no longer wish to be counted a mathematician. That part of my life evaporated many years ago:-)

Tony



Post Edited (2020-11-19 01:07)

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