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How Much Difference Does The Choice Of Wood Make?


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#19 ttonon

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Posted 28 August 2006 - 11:53 AM

I have made few experiments in chamber design, other than to shift partitions in and out slightly, and reduce chamber height. Like many experiments I found these relatively inconclusive, though I think the reduction in chamber height might have improved response and may also have changed the tone in ways I don't like.

What are the factors that can be manipulated in chamber design..?
Parallel sided versus radial chambers
Chambers of smaller or larger cubic dimensions
Shorter chambers versus long
Higher chambers versus lower
Position of pad hole
Gasket material?


Hi Chris,

Most all these factors are discussed in detail in an article I wrote for PICA II, now available for free download at: http://www.concertin.../pica/index.htm (Vol 2, 2005). I'd be interested in any comments you might have.

Best regards,
Tom

#20 Johann

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Posted 28 August 2006 - 02:11 PM

Iíd like to note my own disagreement with this speculation for the following reasons. Johann can perhaps recall that Iíve already posted on the RMMS group that the only way material properties affect resonant frequencies in vibrating systems is through the ratio of stiffness to density, and even there, itís the square root of this ratio thatís important. This is quite universal.


Hi Tom,

yes i can recall what you did write and you know that in most things we think similar.

Still I also can make calculation and the can get close to some noticeable effects in realty.
But the results are usual not usable in realty and if the are compared with results from measurement
the are in most case quit a bit of.

You sure must remember that the calculation for cavity in your paper do not completely go
along with my testing results.
And the are more of theoretical interest as of practical use for construction.

The same apply s for calculation on other wood parts of reed instruments.
I also made test with different wood cases as well.
Spruce makes a big difference to other wood.
But i don't go into this, there is so much written material available abut this, is absolutely no new secrete at all. (Not for reed instruments).

Still in reality, its more a subjunctive human impression that we get when hearing instruments made by different wood body's.
Not the calculations counts, what we like counts. And i cant say it often enough measuring tools are far
limited compared to the human ear.

Your say tensity and mass is the only thing to take into account for calculation.
You are not right in this respect, there are much more physical aspect of a sheet of wood tho be taken in account.
grain direction homogeneity of grain cellular structure and much more.
Its easy to very fay this take your calculations and different types of wood boards and shapes.
And do mode test on them. This has be done before you must know.

If you have some technical staff with absolute homogain structure,
density and stiffness and physical dimensions my be enough to tell the behaver of this sheet of material.

So I believe Dana and my experiences go in the same direction, still for accordions one should not make the mistake
to think there is a major influence or difference if different types of wood are used.

Please do test on yourself and tell us what was the result are, to present calculations and conclusions without having
made tests i don't find this far at all.

best regards, Joahnn

#21 Robin Madge

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Posted 29 August 2006 - 07:04 AM

I remember once making a light-hearted suggestion to Colin Dipper that he should make a "modern art"see-through concertina so that we could see all his interior design at work. He said that he had come across someone who had experimented with using plastics and had tried a perspex reed pan. It sounded horibble.

Robin Madge

#22 bill_mchale

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Posted 29 August 2006 - 08:18 AM

I remember once making a light-hearted suggestion to Colin Dipper that he should make a "modern art"see-through concertina so that we could see all his interior design at work. He said that he had come across someone who had experimented with using plastics and had tried a perspex reed pan. It sounded horibble.

Robin Madge



You know it might be interesting to do some more experimentation with plastics. Like wood, different plastics have different properties; while some sound horrible, others might sound ok.. then again, they might all sound horrible.. After all concertinas are not whistles :)

--
Bill

#23 Chris Ghent

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Posted 29 August 2006 - 09:52 AM

Like Dana I have had experience of changing the wood in the base of the actionbox (soundboard) and noting considerable change in the tone of the instrument.


My test of wood varieties was not controlled, but it was very persuasive. The story went like this...

I made a concertina with a Tasmanian Blackwood (a timber often used in guitars) reedpan, and a sycamore soundboard. All other wood in the concertina was Blackwood. It sounded very sweet.

When I went to make another I could not find any Sycamore and used Blackwood for everything. The Blackwood was the same as the stuff in the first concertina, sawn from the same block. This concertina had a very different tone, a rasp in the note. Not unpleasant, but very pronounced.

One day I realised I could swap the action boxes over as most of the screws would seat OK. The purpose of this was to try the original concertina with the action of the second, which was superior. I was very surprised to discover the tone of both concertinas had markedly changed. The tone largely (that is to say, not completely) had followed the action box, not the reedpan as I had expected. I am not talking of something debatable. It was very obvious.

From the scientific point of view this is not controlled and therefore subjective. But in the same way birds know nothing of Reynolds numbers and can still pull off the flight thing, I know the wood was the difference.

Knowing how to harness this, now thats something else, and I am hoping at some stage to discover a little science to help.

Chris

#24 John Wild

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Posted 29 August 2006 - 06:10 PM

He said that he had come across someone who had experimented with using plastics and had tried a perspex reed pan. It sounded horibble.

Robin Madge


I recall an interview with Hamish Bayne in Concertina & Squeezebox magazine (no.28 Winter 1992-93), in which he said:

"I did make a perspex concertina once; I threw it in the bin, but perspex is a material that is very good to machine. it didn't work. Needless to say it didn't make any sound. When you put the reeds in, they just didn't make any sound. It was uncanny; you could hear the reed vibrating, but there was no tone at all - no nothing. Which made me realise how much of the sound is coming from the wood. There's a lot going on inside there other than just the reed vibrating; the wood affects the tone."


- John Wild

#25 Dave Prebble

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Posted 29 August 2006 - 06:49 PM

[quote name='John Wild' date='Aug 30 2006, 12:10 AM' post='44808']
[quote name='Robin Madge' post='44781' date='Aug 29 2006, 01:04 PM']
He said that he had come across someone who had experimented with using plastics and had tried a perspex reed pan. It sounded horibble.

Robin Madge
[/quote]

Hi,

I recall playing an instrument a few years ago, made with perspex reed pans. It is, I believe, still owned by Mark Davies.

This instrument was made in South Africa but my feeble brain just will not give up the maker's name.

What I do remember is that it was a more than passable instrument and extremely well made.
I was quite surprised at the tone and volume but could not escape the feeling that it would have been better with traditional wooden pans - a far from objective comment I know - mea culpa :unsure:

It does go to show that it can be done and that there are folks out there experimenting with different materials.

Perhaps you would care to add some information and comment Mark ???


Regards
Dave

Edited by Dave Prebble, 29 August 2006 - 06:51 PM.


#26 Dana Johnson

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Posted 29 August 2006 - 10:06 PM

The issues of wood properties I often find drastically over simplified. As Johan mentioned, Wood is not a uniform material. It's modulus of elasticity across the grain is can be half of what it is along the grain. The resonances of a simple wooden plate are not the same as for one that is homogeneous. This also completely ignores the cross linked structure of the medulary rays, which effect how energy is transmitted through the wood.

Any builder of violins and other instruments that depend on the different resonant properties of woods, knows that beside the resonance placements in the instrument which force choices in wood density and thickness parameters for a particular species group ( I mentioned that wood from different trees, or different parts of the same tree can differ markedly in density ) One must also consider the natural damping properties of different species. A luthier willl commonly tap a block holding it at a node and listen to the ring to evaluate this in a subjective but educated way. Some woods go thud ,some clink, some ring remarkably clearly. Many aspects of the wood structure affect this. Beyond this, In violins, it is important to match the drastically different spruce of the top wood with the maple of the back. Remarkably, with a little care it is possible to create the same resonant patterns at the same frequencies in both woods if they are carefully chosen, and if not, mode matching is not possible.

What does this have to do with concertinas? I mentioned before that resonances decrease a reeds output in that range. In a condition where the reed can put energy into sympathetic vibrations of the wood, either through direct vibration from the reed shoe or from the air column, that energy is eventually damped by the bad acoustical connection in the gasket between the reed pan and action plate, and the natural damping properties of the wood itself. This also as Tom mentioned is somewhat dependent on the various wave impedance differences between the vibrator, and vibrated elements. To the extent that a vibration can be sustained in the wooden structure, the contribution of that to the overall sound field is small compared to the vibrating air stream from the pad hole. Concetinas and Accordions are not Guitars or Pianos, where the srtings themselves have almost no ability to vibrate the air and rely on transmitting their energy to the sound bord to do the job. In concertinas as most wind instruments, the pressure waves in the air column are the primary source of sound.

Along the line of the differences in reed pan woods and the generated sound, I do want to mention that the big leaf maple vs Sugar maple reed pan difference was dramatic. The pans involved were geometrically identical to within a few thousanths of an inch in all dimensions, and the reeds were the same.. the big leaf maple used is 80% as dense as the sugar maple. A few years ago I did a different experiment with american sycamore ( strongly cross linked ), What is commonly called soft maple here, but can be red, or white (swamp) maple, or a number of other different species, and sugar maple. They all were dimensionally identical and used the same reeds. The first of American Sycamore sounded soft and dull with Minimum volume capability from the reeds, the second of soft maple increased the volume quite noticeably into a range I considered acceptable and the clarity of the notes improved. The Sugar maple reed pan increased the volume and response of the reeds substantially, and increased the crispness and clarity even more. the Sycamore was actually nearly the same density as the Sugar maple, though not as hard.

Even if the mechanisms I suggest are not convincing,( who am I to speak anyway!) With concertinas, at least, listening experiments while subjective are clear and prounounced. These are not subtle changes in tone or volume. As a maker, I am very much concerned with finding the combinations of material and structure that give me the sound and responsiveness I strive for, understanding mechanisms of action is useful in choosing what to experiment on and what directions to try, but the simple lack of an explaination doesn't invalidate the experience subjective or otherwise. Subjective experience is not invalid experience, it is just less transferrable.

In another line, It is important when gaging the relative influence of the wood on the sound to understand the different connection between the parts involved. In a concertinal of traditional design, the reed is mounted flat against the reed pan. The reed pan needs to resist aquiring the motion of the reed via the reed shoe / reed connection in order for the reed to effectively sustain it's vibration. The reed pan itself is in the plane of the reed, and vibrates in the same direction to the extent it can. On Regular accordion, the reeds are mounted on the reed block, ( for those who aren't familiar with it ) Which is a long block roughly a narrow trapezoid in cross section and somewhat near the length of the keyboard. Usually there are a set of reeds on both sides of the block, sharing a center partition wall. the sound exits holes in the base that match with holes in the board where the pads close the holes. the reeds are perpendicular to the larger surface of this board. The reeds in order to impart motion to the large valve board ( don't know the proper name for this ) will tend to generate a rocking motion in the reed block that can be transmitted to the larger board it is mounted to. This is no where as efficient a connection as the direct no gasket contact with the reed pan on a concertina. The influence of the nature of the chamber walls is a similar one between the two, and while my own experiments seem to say that harder equals brighter, the effect here is not a dramatic one. The way a reed plate is fastened, and the local resilience of the wood it is fastened to also counts, but again, isn't as large an influence. The wave impedance differences ( which are frequency dependant) at the contact point between reed plate and chamber walls may influence the tone as well. But the degree to which the wood can influence the reed is smaller on an accordion than on a Traditional concertina. Not unimportant, but perhaps to the point where the reeds become the dominant factor.

Regarding the position of the pad hole over the reed in the concertina chamber, I only speak from experience. For a hemholtz resonator, the resonant wavelength of a concertina chamber is very short. How do you treat the vibrating reed as part of one of the walls of the chamber. or the relatively huge (in comparison with the chamber size) hole for the pad. I am not at all convinced that idealized calculations accuratley or even approximatly represent what is happening here. ( as in the wood anisotropy example mentioned earlier, and by Johann ) Again, I rely on experience here, actually moving the sound hole up and down the reed chamber ( I can do this easily when I tune my instruments, since on my type, I can tune the reeds in the pan. (intergral end walls )) The tone color changes as the hole is positioned over the tip of the reed, , moves toward the reed center and finally beyond the reed at the base. There are two positions where the reed sounds essentially the same, and another in the center area that has a very different overtone balance and provides a quite unpleasant character to the tone. Again as a listener I find this very pronounced. As a maker, I know where not to put my pad holes and that there is a limit to hole size before it extends into the bad sound area.
Regarding the seeming contradiction between saying wood subtracts from the reeds potential, and the loud raucus reed pan, the Big leaf maple was simply changing the balance of overtones it would support. Sugar maple only supported the ones I like, the Big Leaf maple did a better job of supporting more of certain overtones at a higher level, but that didn't equate to good sound. The damping profile of the sugar maple produced a better tone, not a louder one.

I admire anyone who has the ability to calculate comples things as Tom seems to be able to do, but when calculation doesn't match experience, I take the experience and figure I missed something in my calculating. When Chris, or Johann or myself present our subjective experience, I don't expect anyone to be able to calculate anything from that. It isn't data that is useable for that purpose, but I would appreciate it being treated as descriptively accurate. All of us have substantial experience and have a well developed discriminatory ability. The kinds of sounds a concertina can make vary from simply loud to sublime and then to extreemly subtle, making a good concertina is an exercise in understanding the subtle language of the concertinas sound to know what needs adjusting, and what areas need improvement before the finished instruments leave the shop.

Faulty ideas lead us in the wrong direction, so it is good to listen to different ones. I know I have had my eyes opened more than once, ( like when I discoverd that the natural resonant series of a free reed (plucked or sound driven ) bore no resemblance to the resonant series of a reed driven by airflow.) I found Chris's information on the importance of the action box very useful, and quickly verified it for myself. Johann's information makes me want to spend some more time on reed profile experiments.

#27 ttonon

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Posted 29 August 2006 - 11:32 PM

Hi Johann,

Thanks for your comments.

I may be mistaken, but you seem to require that theoretical calculations be accurate, and if they arenít, they are of no practical use. For instance,

You sure must remember that the calculation for cavity in your paper do not completely go
along with my testing results.
And the are more of theoretical interest as of practical use for construction.


The value of theoretical calculations is often more in the understanding they allow than in whether or not they are accurate. Sometimes all it takes is an adjustment, or a fudge factor, in order to account for difficult issues, but again, the real value in these calculations is in the way they illustrate the physical mechanisms at work, allowing us to extrapolate our knowledge to areas not covered by experiment. We then master a physical phenomenon, allowing us to possibly enhance its expression in what we build. In the paper, I do explain the sources of error Iím aware of. If you havenít already, you might want to read the section ďComplicationsĒ that lists some of these inaccuracies, but Iím sure youíre aware of these things. I think the greater value of the paper is in allowing an understanding how resonance in chambers becomes more likely for the higher pitched reeds, and how lower overtones of the musical tone become more susceptible to cavity resonance as the pitch increases. Such an understanding eliminates a lot of experimental investigation. Perhaps it would be worth sharing your experimental data with me, and we can look at the calculations together.

Your say tensity and mass is the only thing to take into account for calculation.


I think you missed the main point of my last post, which was to evaluate a possible physical mechanism (wood resonance) that would explain the effect changing wood material in a concertina has on musical tone. I clearly did not say what you claim above. Do you have any comments on my reasoning, in the purpose of my post?

You are not right in this respect, there are much more physical aspect of a sheet of wood tho be taken in account.
grain direction homogeneity of grain cellular structure and much more.


I agree that the speed of sound varies with grain direction in wood. Itís interesting to first note that this fact is a direct result of the fact that the Youngís Modulus varies with grain direction, which again illustrates the general principle that the square root of the ratio of stiffness to density is, practically, the only material property that influences the natural frequencies of vibration. I say ďpracticallyĒ here because, in my previous post, I simplified things a little. With some vibrations, Poissonís Ratio also comes into play, in a smaller way, and this ratio is pretty much the same among most construction materials. Also, please note, Iím NOT saying that this factor is the only material property that explains ALL acoustic effects. Itís interesting to note that Youngís Modulus in the longitudinal direction for most woods is from roughly 10 to 20 times larger than that across grain. One exception is Oak, with a ratio of about 2.5. For Spruce, choice material for the top plates of string instruments, itís from 13 to 24. Since the density is the same in both directions, this means that the speed of sound will be greater along the grain by a factor about equal to the square root of this ratio say, about 3 to 5. This is one reason why the aspect ratio of bowed string instruments is approximately 3 Ė sound moves out to the edges more or less uniformly, enabling many mixed vibrational modes. An added complexity is that the sound speed varies more or less continuously with grain angle, achieving the above maximum and minimum at zero and ninety degrees. (Let me also mention that, for sound waves in wood, one uses the dynamic Youngís Modulus, which is about 10% greater than the static value, and it varies inversely with moisture content, but this is getting boring.)

In any event, letís speculate and suggest that this non-homogeneous property of wood might explain why different woods behave differently in a concertina. To explore this, Iíd first like to ask Frank, Dana, Richard, Chris, and other builders if they orient the grain in preferred directions when building. If they donít, Iíd tend to think the effect isnít important, since so little can get by these craftsmen :-)

Without knowing this, Iíd have to guess that thereíd be little influence of grain orientation in the reed pan or action board of radial reed layouts (Wheatstone?). With parallel arrangement (Jefferies?), one might choose to orient either the long axis or the short axis of the cavities with a particular grain orientation. After building several concertinas and evaluating their musical tones, conclusions may be drawn. Thatís a lot of work. Still in my guess mode, I donít see much merit in this, and one good reason for my skepticism is that, with all the cavities attached to the reed plate, the resulting structure is much more rigid than the simple board, and so too with the action board, which often has another rigid plate attached (to guide the buttons). These additional members, I think would bury a 40 % change of sound speed with grain orientation.

If we really want to know the answer to the question of the original post, a good experiment to do would be simply to measure the amplitude of wood vibration in the different wooden members. Knowing this number would surely spawn a lot of thinking. But Iím not inclined to do such an experiment until Iím more convinced, for whatever reason, wood material is important.

The same apply s for calculation on other wood parts of reed instruments.
I also made test with different wood cases as well.
Spruce makes a big difference to other wood.


So I believe Dana and my experiences go in the same direction, still for accordions one should not make the mistake
to think there is a major influence or difference if different types of wood are used.


You have me confused. Do you think wood material is important to musical tone in concertinas or not? Perhaps my memory fails me, but as I recall, didnít you once make accordion reed cavities from balsa wood and found no noticeable effect?

In any event, I appreciate your comments.

Best regards,
Tom

#28 ttonon

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Posted 29 August 2006 - 11:51 PM

Hi Chris,

This concertina had a very different tone, a rasp in the note. Not unpleasant, but very pronounced.


Was this ďraspĒ present throughout the musical range of the instrument?

I was very surprised to discover the tone of both concertinas had markedly changed. The tone largely (that is to say, not completely) had followed the action box, not the reedpan as I had expected. I am not talking of something debatable. It was very obvious.


How was the tone changed? Did the first concertina (with Sycamore soundboard) then become raspy and the second concertina then sound sweet?

As you know Iím skeptical that material alone could account for the change in sound. Some organ pipes are made of wood. The wood material does not directly affect the sound. The material that a flute is made of does not directly influence the sound of the flute. The material that a clarinet is made from does not directly influence the sound of the clarinet. The material that comprises the bell of a brass instrument does not directly influence the sound of the instrument (Within limits. Someone in Germany built a bell out of soft rubber, and there was a measurable effect, but this represents a change in material properties by more than a factor of 1000.) It is true, however, that different materials allow or produce different geometrical changes. With the flute or clarinet, for instance, a metal allows much finer detail and sharper corners around the tone holes than does wood. Such subtle changes can make a convincing change in tone.

The above examples involve musical instruments that utilize a vibrating air column to generate sound, and this air column vibrates with relatively large amplitude throughout the instrument. With the concertina, sound is generated right at the reed tip, like a siren, engaging a small amount of air to vibrate at large amplitude before escaping the instrument. If the above instruments are not influenced directly by material of construction, why should the concertina be different?

This is an old story with musical instruments. There have been many examples of people claiming to hear things that, in reality, are generated from within their own brains. The story with flutes went on for decades, until definitive experiments proved the above statement. The results of blindfold tests with different violins show that many "experts" are simply wrong about their ability to identify "pedigree" instruments among others. There are also many examples in the Hi Fi world, where, for instance, some people claimed silver plated speaker wire makes a difference, which is nonsense. Iím not suggesting that youíre in that category, because human experience is very vast. I realize you donít expect me to believe what you believe based on your single experience, and I see no problem with our different views.

Iím left right now only to ask you to be sure that some subtle, indirect effect isn't at play. Are you absolutely sure that, when you changed action boards, nothing else changed? For instance, could it be that one action board permitted the gaskets to fit much more tightly than did the other? Perhaps the screw patterns were different, allowing more rigid assembly with one action board? I suggest you try to think about all the factors that you definitely know influence musical tone and be sure that none of these enter into the action board exchange.

Knowing how to harness this, now thats something else, and I am hoping at some stage to discover a little science to help.


Iím thinking, but so far cannot convince myself of a physical reason for it, and this could be due to my limited experience. I would very much like to hear the examples you and Dana note, but that's not easy to do, and so I'm confined to my theoretical perspective, which I admit, is limited. Perhaps, hopefully, someone will suggest a physical mechanism I can believe plausible. In the meantime, letís keep talking.

Best regards,
Tom

#29 Dana Johnson

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Posted 30 August 2006 - 01:20 AM

The value of theoretical calculations is often more in the understanding they allow than in whether or not they are accurate. Sometimes all it takes is an adjustment, or a fudge factor, in order to account for difficult issues, but again, the real value in these calculations is in the way they illustrate the physical mechanisms at work, allowing us to extrapolate our knowledge to areas not covered by experiment.

I remain a bit unconvinced by calculations that require fudge factors. While in some cases, the calculations do actually represent what is happening, in others, they misrepresent it. Epicycles were a "fudge" factor used to explain why planets went retrograde. Astro physicists used to think they were on the right track if they were within a couple orders of magnitude of observations. (not all that long ago either.) If theory can't account for observable phenomenon, you can't very well extrapolate from it. You may have a lot of questions about our observations, but seem happy to assume they are wrong until we somehow come up with a theory you are happy with. What I'd prefer is for you to send me a design for a good wave impedance probe.

While experts may not have been able to match maker to violin, they probably could have told a good violin from lousy one.

Other things you may want to add to your calculations ( what are you calculating anyway?) the distributed mass of the reeds on a concertina reed pan which in some cases outweigh the reed pan. What I have been talking about is the resistance of the reed pan to motion at different frequencies via the transfer of momentum to it from the reed / shoe assembly. Given that for an average reed in the mid range of my concertinas, it takes 16-18 grams to deflect the reed just 2 degrees, and a typical reed in full swing moves in an arc of more than 30 degrees, a few hundred to a few thousand times per second, the energy involved isn't insignificant. Regardless of any resonance structure, since wave impedance is is different at different frequencies, how does the impedance / frequency curve match the impedance of the reed? especially as you say, we have different sound propagation speeds in every direction of the reed pan. Now throw in the chambers and wall orientations, and I don't think you have a very simple system anymore.

The grain on my reed pans is oriented paralell to the chambers ( grid style, not radial ), is as close to perfect quarter as I can get it, and since my reed pans are cut from a block, not made with glued on partition walls, it is as stable as I can get it. and that is the purpose of the orientation. Jeffries style reed pans are all oriented like this, Radial wheatstone style red pans are not.

#30 Johann

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Posted 30 August 2006 - 03:45 AM

I admire anyone who has the ability to calculate comples things as Tom seems to be able to do, but when calculation doesn't match experience, I take the experience and figure I missed something in my calculating. When Chris, or Johann or myself present our subjective experience, I don't expect anyone to be able to calculate anything from that.

Dear Dana Johnson,

Thank you for taking your time all you write i could not explain better (even i could us the English language as native speaker) and meet my thinking completely.
I may be a bit more like Tom in some way, well because i like to find mathematical expressions to be able to calculate in advance.
But at the moment my formulas for calculating reed chambers are far more complex as the formulas Tom did present and the still cant be used in praxis the experience we make is much more important.
So i keep on the same way as you do.

Regarding the position of the pad hole over the reed in the concertina chamber, I only speak from experience. For a hemholtz resonator, the resonant wavelength of a concertina chamber is very short. How do you treat the vibrating reed as part of one of the walls of the chamber. or the relatively huge (in comparison with the chamber size) hole for the pad. I am not at all convinced that idealized calculations accuratley or even approximatly represent what is happening here. ( as in the wood anisotropy example mentioned earlier, and by Johann )

Yes correct, and Tom states in his paper the t his calculation should not be used for the actual construction the are more of a background of understanding the fundamental things going on. My testing results fit more or less his calculations the fit in a way that his explanations make some sense, but only in mid range pitch it the experimental results and Toms Table get close in higher or low pitch the errors are traumatic and show that the real situation is much more complex.
I could post this comparing tables here as well as i have posted them to Tom, still i think the would not be of practical use and difficult to understand. I observed absolutely the same as you describe what happens if the pad hole position relative to the reed position is changed. As this change in ton color (and more or less in pith as well ..)so affect all variations of changes in cavity geometry the sound. for instance if the back wall is variable and its angle is changed the same or similar affects take place. So it is sure not only Volume and the pad opening (Helmholz) (nor the quarter wave resonance) resonance that in fluencies the sound color. If Volume and pad hole is kept the same and the angle of the back wall is mounted variable one can notice this very distinct and even would be possible to present a Spectrogram and a sound sample. I don't have one ready at the moment to post i would need some time to do the tests again because i lost a lot of documents with a Hard disc breakdown. Still quoter wave resonant plus Helmholz resonance are the first that do also effect the ton color. As you state resonance is a NEGATVE peek and should be avoided. It is erroresly often thought that resonance in reed instrument lead to more Volume. (I don't say that there arr some other phenomenons that lead to amplification and more sustain in the sound. More to learn in this respect). So could think that there are many negative peeks resulting from varies resonating spots one is the quarter wave length an other is the Volume resonance (Helmholz) and then we may add different modes from the wood used to build may parts of the instruments. We dont know how strong each of the negative peaks contribute, i can well see the differences in the Spectrogram's in and on different wood used but i am far away to tell the exact frequency's. Still all is better distinctive via or human ear. Than the sound formating of all parts of a box cant format what is not produced by the reed and its air column the first place. So a reed with different dimensions will generate little different sound but it need the surrounding formating factors to support or to damp parts of the possible sound spectrum. So if the reed cant produce some frequencies (dis harmonic overtones, harmonic overtones are always present) the never will appear except via pith change feedback.
Or the other way round the formating factors can only damp some of the possible overtones produce able by the reed and its air column.
Practical observations back tis very well.
Reed sets made by indifferent factory's are suitable for some boxes are not subtable for others and the other way round.
For instance especially with cassoto instuments even some high qulity rees cnt be used.
This is a practical experience a friend from an well known accordion builder tells me, i cant tell more details the want to keep this to them self.

To my person:

Being NOT a professional accordion builder, I am a professional Sound - Electronic - Engineer and teacher for microelectronics and Computer Electronics Certified and Trainer for some well known Products, but retired from my regular teaching work. I started as Apprentice for repairing Televisions and wireless in the mid 60is. Worked for one Year in London after i had finished may exams as Tap recording Engineer. Then i made more Exams and i was in charge of a little repairing department for some Years where we also did do a lot of Sound equipment supplying big event with acoustic including big arenas. After more Exams i change completely to micro electronic design and construction and eventually in 1984 i switched to Computer technic and electronic teaching in most cases the practical aspects of this fields.

In the past up to about tree years back I covered nearly all fields of modern electronic designs.
Actually i would have built a electronic accordion if it would have been possible to get the sound i want, i switched back to acoustic accordions.
I stared to experiment with reed instruments about 20 Years ago and the last 6 Years it is getting may main interest and work i am doing. 25 years back I was able to learn from a retired Vienna Accordion builder in 3rd generation some major things like reed making and bellows building, but i never did this work on a regular base just for fun up to the last few years.
I am now 55 Years old and retired from my regular teaching job doing occasionally some work in my profession, because it pays the bills beside the money i get for my retirement. So i do have all the time i want now to do more on building diatonic boxes and doing more research.

#31 Johann

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Posted 30 August 2006 - 04:31 AM

Dear Tom Tonon,


You have me confused. Do you think wood material is important to musical tone in concertinas or not? Perhaps my memory fails me, but as I recall, didnít you once make accordion reed cavities from balsa wood and found no noticeable effect?


Yes is important, but for accordions it is often thought is a major influence.
Or some builders here say it don't count at all, because the use of ply wood for cases is easier in accordion production.
But even this builder do a lot on the reed block design and use of wood for the reed block.


It comes more on the 3rd place to be taken in account from may few point.

Balsa for reed blocks actually don't make a lot of difference, yes true again and i like it.

First comes the reed then the dimensions of the chamber and a other construction dimensions than the wood.

And my thinking may change a little bit if i do more tests.

An other thing is: first comes all must be very stiff and stabil other vice very negative effects of resonance can be noticed. So ply wood is a good average joice with having more a damping effect as an resonance effect.
In most cases 4 layers of spruce or beech ply with on layer veneer of any wood is used for the case.

So the results are justify able in most cases no matter what wood is used, but better is to keep to the traditional wood. speaking about diatonic accordions. So one has not be vary anxious if one uses something else but in every case the result ma be surprising and sure a bit different.
I also can well imagine that concertina construction is more sensitive to the use of wood.
Single reed, flat construction with panes ...
Rigidness does not mean there is no vibration on this parts.



On the rest, i am quite happy with your few point,after now you did say more about it.

#32 Theo

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Posted 30 August 2006 - 04:35 AM

So having read all of this discussion(and undurstood most of it) would the following summary be near the mark:

In free reed instruments the vibrating reed is the source of sound and other parts of the instrument in effect subtract from that.

In violins, and other stringed instruments, the vibrating string is the source of the sound, and other parts of the instrument assist in coupling the vibration to the air.

Therefore there is a fundamental difference in design: violin makers aim to make their instruments to be as resonant as possible, concertina makers aim to make their instrument resistant to vibration.


????

Edited by Theo, 30 August 2006 - 04:35 AM.


#33 Johann

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Posted 30 August 2006 - 06:47 AM

Dear Theo,

[quote name='Theo' date='Aug 30 2006, 11:35 AM' post='44833']
So having read all of this discussion(and understood most of it) would the following summary be near the mark:

In free reed instruments the vibrating reed is the source of sound and other parts of the instrument in effect subtract from that.
[/quote]
free reed + Air column in motion. And undoubtedly most of the sound get radiated in a direct way not via any wood parts.
But one has to see the complete system, reed and air colon vibrate more or less in sympathy with the sound formating parts.

the rest of this comes very close resonating spots are as far as i could observe do have usual a NEGATIVE "Vally" (Curve in the sound envelope) Still there are certain arias of the sound spectrum that can as well be seen as POSITIVE Peaks but usual this arias of the sound envelope do cover a wider range of the spectrum. If i speak of the sound spectrum i talk about spectrograms i have compared on different boxes without using reeds at all. I compared different helicon bass constructions and wood type used for the bass section with withe sound (noise) generated by a inductive speaker placed instead of the reed. Helicon chambers and reeds are fairly big so this is possible. The difference in sound color is again noticeable be the ear much more as through the visualization in the spectrum.
This test arrangements wold be suitable to get "objective" results from a scientist's few point. So one could send a lot of time verifying and documenting different constructions and different material used WITHOUT the reed as sound generator.
But i don't provide at the moment with this tests because i am satisfied already and for the end result there is not much to gain because the complete system with reeds counts.

Sustain of tone is an other question, and as with all the short answer is not complete.
[/quote]

[quote name='Theo' date='Aug 30 2006, 11:35 AM' post='44833']



In violins, and other stringed instruments, the vibrating string is the source of the sound, and other parts of the instrument assist in coupling the vibration to the air.
[/quote]

yes simplifying main radiation of the sound via Resonator.


[quote name='Theo' date='Aug 30 2006, 11:35 AM' post='44833']


Therefore there is a fundamental difference in design: violin makers aim to make their instruments to be as resonant as possible, concertina makers aim to make their instrument resistant to vibration.

[/quote]


Also to much of a simplification, but basically right.

If it war only to restrict any sympathized resonance this is not possible and it is more a question of the right damping in the right frequency ranges. To get the instrument sing similar to the the human voice.

In the end it douse not matter that the formating works more as damping or amplifier's certain frequency's the end result is similar to String instruments.

And with all this the transformation and sustain that happens with spruce and maple ans some other wood types, is not answered with all this.

It is also funny that an easy tapping on the wood board by holding the board on one of its vibrating nodes and charging to the resulting tone tells more as all measuring.
I prefer to go along with Dana Jonson, he really knows a lot about this.

#34 Johann

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Posted 30 August 2006 - 07:11 AM

"... it didn't work. Needless to say it didn't make any sound. When you put the reeds in, they just didn't make any sound. It was uncanny; you could hear the reed vibrating, but there was no tone at all - no nothing. .."


- John Wild


Hi John Wild,

cant imagin that the reeds did not sound at all. -- hoorible -- differnt -- less volume -- i woul blive.

#35 Richard Morse

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Posted 30 August 2006 - 09:04 AM

You have me confused. Do you think wood material is important to musical tone in concertinas or not? Perhaps my memory fails me, but as I recall, didnít you once make accordion reed cavities from balsa wood and found no noticeable effect?

Yes is important, but for accordions it is often thought is a major influence.Or some builders here say it don't count at all, because the use of ply wood for cases is easier in accordion production. But even this builder do a lot on the reed block design and use of wood for the reed block.

I've played many accordions in which some have plywood and others aluminum soundboards (as we call the pallet/pad pan item that the reedblocks are secured to) - including Wurlitzer and Hohner PA's and Paolo Soprani and Castagnari BA's. Some of these are models are "twins" where their production had changed from wood to metal - I was hard pressed to discern much of any sound/reponse difference. It seems to me that the method to which the reedbanks are secured to the soundboard has a greater sound/response difference than what material the soundboard was made of.

I also note that most reedblocks I've seen are made of softwood bodies and hardwood shoes (or bases - where the exit holes are). Rarely is the top end of the banks or body made of hardwood. I've also seen accordions with plastic reedbanks. One single moulding of plastic per bank. These accordions DID sound somewhat different though very much within the range of "normal" accordions, and the difference could have been due to other factors.

-- Rich --

#36 Chris Ghent

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Posted 30 August 2006 - 09:31 AM

Hi Chris,

This concertina had a very different tone, a rasp in the note. Not unpleasant, but very pronounced.


Was this ďraspĒ present throughout the musical range of the instrument?


Yes, but it became less the higher in the concertina you went.

I was very surprised to discover the tone of both concertinas had markedly changed. The tone largely (that is to say, not completely) had followed the action box, not the reedpan as I had expected. I am not talking of something debatable. It was very obvious.


How was the tone changed? Did the first concertina (with Sycamore soundboard) then become raspy and the second concertina then sound sweet?


When the first concertina, which had a sweeter sound and a sycamore soundboard, was given the blackwood soundboard, it became raspier. And the second concertina gained a sweeter sound.

As you know Iím skeptical that material alone could account for the change in sound. Some organ pipes are made of wood. The wood material does not directly affect the sound. The material that a flute is made of does not directly influence the sound of the flute. The material that a clarinet is made from does not directly influence the sound of the clarinet. The material that comprises the bell of a brass instrument does not directly influence the sound of the instrument (Within limits. Someone in Germany built a bell out of soft rubber, and there was a measurable effect, but this represents a change in material properties by more than a factor of 1000.) It is true, however, that different materials allow or produce different geometrical changes. With the flute or clarinet, for instance, a metal allows much finer detail and sharper corners around the tone holes than does wood. Such subtle changes can make a convincing change in tone.


I accept the argument that material differences allow different technology and create tone changes through design, but find it hard to accept some of your examples. As an example, I have an acquaintance who is the trumpet player in our premier orchestra. He has a large number of trumpets. He draw distinctions between instruments that are shaped similarly but made from different material. One example was a trumpet of which he has two, one plated, the other not. He chooses which one he plays according to their tone. One is a brighter sound than the other. Again it is a subjective example.

This is an old story with musical instruments. There have been many examples of people claiming to hear things that, in reality, are generated from within their own brains. The story with flutes went on for decades, until definitive experiments proved the above statement. The results of blindfold tests with different violins show that many "experts" are simply wrong about their ability to identify "pedigree" instruments among others. There are also many examples in the Hi Fi world, where, for instance, some people claimed silver plated speaker wire makes a difference, which is nonsense. Iím not suggesting that youíre in that category, because human experience is very vast. I realize you donít expect me to believe what you believe based on your single experience, and I see no problem with our different views.


I understand these examples and accept I am capable of making similar assumptions. The example I have quoted I have only quoted because it was so marked. Unfortunately I cannot reproduce it and record the difference because one of the concertinas is in Ireland.

Iím left right now only to ask you to be sure that some subtle, indirect effect isn't at play. Are you absolutely sure that, when you changed action boards, nothing else changed? For instance, could it be that one action board permitted the gaskets to fit much more tightly than did the other? Perhaps the screw patterns were different, allowing more rigid assembly with one action board? I suggest you try to think about all the factors that you definitely know influence musical tone and be sure that none of these enter into the action board exchange.


I can make no guarantees of this; as you know the factors are so numerous it is almost impossible to isolate a single factor without an immense research budget. Did I always turn to the right while playing one and to the left while playing the other? I didn't even play them for another person. What I can say, with all the freedom of the practitioner over the scientist, is I know what I think and I am going to plug that in my work until I find a different understanding. I don't say this in any sense of opposition to your point of view, it is just the only course open to me.

Chris




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