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How Much Difference Does The Choice Of Wood Make?


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#1 asdormire

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Posted 18 August 2006 - 09:24 PM

I was curious about this any way, but I just looked at a Canadian site where the maker was talking about using a wide variety of tonewoods in his concertina. I have a passing interest in instrament making, and we have enough stringed instraments around here that I know wood makes a real difference in the sound, but I would think the reeds would make more of a difference in the concertina. so what do I need to know?

Alan

#2 Frank Edgley

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Posted 19 August 2006 - 11:12 AM

I'm not sure if mine is the site you mentioned, but I will make a few observations:
-The most important single factor in the tone is the reeds. This is also true regarding sensitivity and response.
-Also important is the size and shape of the reed chambers.
-The size & location of the vent holes also affects tone.
-The wood of the reed pan (soundboard) is also important.
-The wood of the body of the instrument is more controversial. I think there may be a subtle difference, with the denser materials giving a "harder", "cleaner" tone, and softer woods a more "rounder" tone. It's difficult to come up with words to describe tonal qualities, though. This difference is in no way as pronounced as it would be in an instrument as a violin or guitar, where the vibration of the body of the instrument is a significant factor.

Without question, however, is the fact that tone does "improve" with age. How long and how often it is played, and how vigorously (roughly) it is played are the factors here. Obviously the extent depends on these and other factors. Response may be another question. A "dog" of a concertina, with inefficient air usage, and poor reeds, will never be a great player no matter how much it is played. In fact, These instruments, because of poor design and materials get worse after a couple of years of playing..

#3 Dave Prebble

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Posted 19 August 2006 - 05:02 PM

Hi Frank,

I agree with your comments fully. The reeds are the biggest factor while the type of timber used will have subtle but noticeable effects.

What a pleasure to be able to post such comments without being demanded to test, measure and 'proove' everything :lol: :lol:

Thinking on the word 'tonewood' - this term is also used to describe spruce employed in making fiddle tops. Many early concertinas used very thin spruce baffles and I just wonder if the replacement of these with say a leather baffle would have any noticeable 'material related' effects.

Regards Dave

#4 bill_mchale

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Posted 20 August 2006 - 10:04 PM

I'm not sure if mine is the site you mentioned, but I will make a few observations:


If it aint you Frank, I would really like to know who it is; I thought I knew the websites of all North American and European Concertina Makers.

--
Bill

#5 Dana Johnson

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Posted 23 August 2006 - 08:03 PM

Frank has the right of it, though I give the wood a lot more credit for influencing things. It may be different on accordion reeded concertinas, but on instruments with traditional reed pans etc., Wood can have a major influence on tone playability and responsiveness. Woods used in concertinas have enough variability in density and other factors even in pieces of the same species, that some care needs to be taken to get wood that gives the sound you are after. Timbre doesn't change much from piece to piece, and has more to do with chamber depth, and shape. Brightness or softness of tone is limited by the reeds, but how much of that brightness is realized depends on the wood used. Responsiveness is also limited by the reeds, but can dramatically be affected by wood and quality and method of construction. A good reed is essential, but put it in a bad box and you have wasted whatever you put into it.

I am always considering ( albeit conservatively ) different types of wood in concertinas and have sometimes been surprised by my tests, getting results that were quite different than I'd guessed. What I found interesting is that the choice of reed pan wood may be important, but nearly as important is the choice of wood in the action pan when it comes to tone. Beyond tone considerations, stability has helped to determine the choices that were made in traditional instruments. Some parts are little affected by changes in the humidity, while others are substantially affected. Large instruments are affected more than small ones, so may use different materials in shrinkage sensitive areas than are required in smaller instruments.

There are even more than one good set of wood choices you can use. I've seen and played some great concertinas that didn't use the traditional English Sycamore or anything resembling it. Proof is in the pudding, but for anyone interested in making concertinas, don't make more assumptions than you need to get the job done, and be ready to completely revise them. If you are having problems getting what you are looking for, consider changing the wood.
Dana Johnson

#6 Chris Ghent

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Posted 23 August 2006 - 10:17 PM

I'm with Dana.

If concertina reeds are made to the highest possible standard the tone variation in them is minimised.

So if everything in a concertina was made to its highest possible specification the tone variable in reeds would have been removed and the wood variable would remain. Therefore I would say the answer to the original question is; wood is the real variable in concertina sound.

As evidence for this I offer the following. Some time ago I was participated in a number of tests involving transplanting reeds from one concertina to another. We found a Lachenal reed placed in a Jeffries concertina would disappear from the tone point of view as far as a listener was concerned. The player would tend to know exactly where it was because of response issues. If the concertina was played loud and fast even the player could not find it. The swap in the opposite direction was similar though the player found the Jeffries reed harder to find.

In order to discuss this I suspect you need to talk of at least two different "tones", one, the background overall tone reflecting the choice of wood, and two, the changes in tone created by increasing/decreasing the tolerances between the reed and the frame. I choose this aspect of reeds because it seems to be the one that makes the biggest difference. Other differences may come from reed taper, slot shape etc but I think they are small.

One of the difficulties in making progress in investigating the tone of concertinas is there is no language for describing the different sounds. You are reduced to saying things like, there's more "whoa" in that one, this one has more "whea".

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.

In closing, I note Dana's words "for anyone interested in making concertinas, don't make more assumptions than you need to get the job done, and be ready to completely revise them". How true. If what I say in this post ends up being one more example of this, so be it, at least I will be further along.

Chris

Edited by Chris Ghent, 23 August 2006 - 10:18 PM.


#7 Richard Morse

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Posted 24 August 2006 - 08:42 AM

So if everything in a concertina was made to its highest possible specification the tone variable in reeds would have been removed and the wood variable would remain. Therefore I would say the answer to the original question is; wood is the real variable in concertina sound.

Wait a minute! What about the way the reeds are mounted and the chambers? I submit that that sort of *design variable* creates huge sound differences.

Some time ago I was participated in a number of tests involving transplanting reeds from one concertina to another. We found a Lachenal reed placed in a Jeffries concertina would disappear from the tone point of view as far as a listener was concerned. The swap in the opposite direction was similar though the player found the Jeffries reed harder to find.

I think this is could be attributable more toward the chamber shapes and reedpan thickness rather that wood species. After all, they both used maple. The variable here is the *design*.

In order to discuss this I suspect you need to talk of at least two different "tones", one, the background overall tone reflecting the choice of wood, and two, the changes in tone created by increasing/decreasing the tolerances between the reed and the frame. I choose this aspect of reeds because it seems to be the one that makes the biggest difference. Other differences may come from reed taper, slot shape etc but I think they are small.

But if you don't put much effort into the reedpan and chamber design you can still wind up with a dog. Consider the huge difference endstops on radial chambers makes. Or the depth of (especially of high reed) chambers, or the difference between radial and parallel chambers, or flat on the pans or in banks perpendicular to the pans, or rubber gasket mounted reeds versus dovetailed ones....

-- Rich --

#8 Chris Ghent

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Posted 24 August 2006 - 10:42 AM

Wait a minute! What about the way the reeds are mounted and the chambers? I submit that that sort of *design variable* creates huge sound differences.


Rich,

I don't think I was taking too narrow a view of the meaning of "reed". When people say reeds I think of the tongue and the frame, not the reedpan or the chambers. So I was saying I did not think the tongue and the frame of the reed were more important factors in tone than the wood. I did not mean to give the impression I thought there were no other factors.

Some time ago I was participated in a number of tests involving transplanting reeds from one concertina to another. We found a Lachenal reed placed in a Jeffries concertina would disappear from the tone point of view as far as a listener was concerned. The swap in the opposite direction was similar though the player found the Jeffries reed harder to find.


I think this is could be attributable more toward the chamber shapes and reedpan thickness rather that wood species. After all, they both used maple. The variable here is the *design*.


Sorry Richard, don't get you. I'm saying the tone went with the concertina not the reed. You are saying the chamber shapes and pan thicknesses in the two concertinas are different. This would indicate these are not factors?

In order to discuss this I suspect you need to talk of at least two different "tones", one, the background overall tone reflecting the choice of wood, and two, the changes in tone created by increasing/decreasing the tolerances between the reed and the frame. I choose this aspect of reeds because it seems to be the one that makes the biggest difference. Other differences may come from reed taper, slot shape etc but I think they are small.


But if you don't put much effort into the reedpan and chamber design you can still wind up with a dog. Consider the huge difference endstops on radial chambers makes. Or the depth of (especially of high reed) chambers, or the difference between radial and parallel chambers, or flat on the pans or in banks perpendicular to the pans, or rubber gasket mounted reeds versus dovetailed ones....


I am in agreement with you on this...

Chris

#9 Richard Morse

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Posted 24 August 2006 - 11:33 AM

What about the way the reeds are mounted and the chambers? I submit that that sort of *design variable* creates huge sound differences.

I was saying I did not think the tongue and the frame of the reed were more important factors in tone than the wood. I did not mean to give the impression I thought there were no other factors.

But you did say "wood is the real variable in concertina sound." which lead me to think that you thought other factors were much less important.

I'm saying the tone went with the concertina not the reed. You are saying the chamber shapes and pan thicknesses in the two concertinas are different. This would indicate these are not factors?

I don't understand you last sentence but I agree that the tone went with the concertinas because the concertinas were designed/constructed differently.

#10 ttonon

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Posted 24 August 2006 - 09:00 PM

As evidence for this I offer the following. Some time ago I was participated in a number of tests involving transplanting reeds from one concertina to another. We found a Lachenal reed placed in a Jeffries concertina would disappear from the tone point of view as far as a listener was concerned. The player would tend to know exactly where it was because of response issues. If the concertina was played loud and fast even the player could not find it. The swap in the opposite direction was similar though the player found the Jeffries reed harder to find.


Hi Chris,

Itís nice to be back after a long absence.

I tend to agree with Richard on this one. Letís simplify, by saying that a concertina is comprised of 1) itís reeds (plates, or carriers plus reed tongues) and 2) everything else, called ďdesign.Ē Your experiment may actually prove that the design can be more important than the reeds, in so far as steady state tone goes. Included in the design, of course, is the material of the wood. So in order to resolve this, we should ask, what evidence is there for one to say that this design aspect is at all important? What wood materials were used in both concertinas? What differences were there in the other aspects of the design?

Now, I canít say wood material has no importance, but before I believe it does have a prime importance, Iíd have to hear some kind of physical reasoning behind it, and in saying this, Iím only trying to push the discussion further. What possible physical mechanisms can be at play, in order to give weight to your belief? Are there direct acoustic factors, such as resonance, or perhaps thereís some kind of indirect effect, such as the possibility that different woods enable different dimensional relationships between the parts? The latter possibility occurs, for instance, in flute making; metal construction allows more precise hole geometries than does wood construction, producing audibly Ė and measureably - different results in the musical tone.

Best regards,
Tom

#11 Dana Johnson

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Posted 24 August 2006 - 10:50 PM

I mentioned in the beginning that Chamber shape and depth and to a lesser extent reed pan thickness, have an influence on the characteristic sound of a concertina. Chris has a point when he says we lack a common language, but Once I took a cheap accordion reed and cut the plate away till it fit in a Wheatstone reed pan, temproarily cemented it in place and it no longer sounded like an accordion reed at all. It didn't play as easily as the original reed, but it had the characteristic "Wheatstone" sound.

Chamber design seems to be the primary controlling factor here. There are a number of design factors that also have a strong influence on tone, like pad hole location relative to the reed, openness of fretwork, and more, but the point I was trying to get at is that if you hold all the geometric aspects of the design constant and merely change the wood involved, you can have dramatic changes in the tone quality. Certainly reed mounting has a big influence on the sound, (note the above accordion reed experiment )

For those who want some sort of mechanism to explain it all, I currently subscribe to the "wood in contact with reed shoe" as selective filter theory. All the portions of a reed pan and indeed the action pan in contact with it via the sealing gaskets, vibrate more or less when attached to the moving mass of the reed/ reed shoe system. Planar surfaces have many different natural resonance patterns at multitudes of different frequencies. When a reed harmonic comes close to one of these resonances, the wood wants to vibrate in sympathy with the harmonic, and literally steals the energy from the reed. the energy is then is damped out and turned into heat by the wood's natural damping coeficcients and the losses via all the gaskets. The pitch location of the natural resonances of the reed pan etc. determines the relative strengths of the different harmonics each reed is allowed to express. I could go into considerable more detail here, but this isn't the place for it.

I tend to make a distinction between Tone Character and Tone Quality. Character I consider a result of design, and covers things like "nasal sounding", "oboe like" "clarinet like" presence of "Formants" like EEEE, ARRR, OOOO, and that sort of thing. Tone Quality I consider things like brightness, brassiness, dullness, softness, clarity, loudness etc. which can be present in any "Tone Character". I find that Tone Quality is controlled by the wood involved, hardness of materials exposed to the sound path, type and method of gasketing, firmess of contact between the reed pan chamber walls and the action pan, and reed clearances.

If you were looking at an oscilloscope trace, the Character would be represented by the overall shape of the waveform, while the Quality would be represented by smoothness of the boundary and the overall amplitude. By Quality , I don't mean good or bad. Brightness would be a quality, perhaps desireable to one person and not to another, but it would be visible as a distinct overlay of different high frequency harmonics on the main wave form.

If the wood used is either too thin, or thicker but not very stiff, the lowered frequency of it's resonances can intrude into the range that controls the "Character" In this place, the design includes how the wood is used, and is species/ property dependant. It is the job of the maker to be sure the dimensions of his parts fit the properties of the species and even particular sample of wood used.

My experience still remains that you can have a great design , but if you execute it with a poor choice of materials, or bad workmanship, design won't be of much help. You may have an instrument that has the Wheatstone sound, but still is lousy to play and for all it's pedigree, sounds terrible.

#12 Chris Ghent

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Posted 25 August 2006 - 08:33 AM

Excellent stuff Dana..! You know of my experience of changing action boxes between two instruments with very different tones and with very different species of wood as the soundboard, and finding the majority of the tone followed the soundboard. By majority of tone I believe I am talking about what you call tone character. I think this might also be what Tom referred to as steady state tone?

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?


It seems to me, with the exception of some low notes, people universally make chambers as small as possible, presumably to improve response times. The chamber ends after the reed shoe, the height is dragged down to leave enough room so the reed doesn't hit the soundboard. The pad hole is always at the far end from the reed. Is this "design for tone" or expediency to get a fast concertina?

If chamber design is ruled by response, doesn't that leave wood; species, density/ thickness as the only tone modifier left to work with?

Chris

Edited by Chris Ghent, 25 August 2006 - 08:35 AM.


#13 Johann

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Posted 25 August 2006 - 01:34 PM

I am in some experiments on diatonic helicon boxes.

Richard and Ton and may be some other do know me because we exchanged mails before.

First my intention was wood makes the biggest difference in sound quality and sound formation.
All the boxes i built are different in many aspects, so the resulting sound is quite different if one compares the boxes.

Then i do have a few old boxes and the sound is different again.

The last experiment was rebuilding one old box with the same dimensions as an old two row box.
The sound of the old two row box is liked by me very much.
After i had taken all wooden parts apart i cleaned all and actually rebuilt the complete 3 row box.

First the reeds are the same type of this two boxes. Old German DIX Zinc reeds in good condition.
One box is with 2 rows the other is with 3 rows.
Dimensions are equal because the same Factory made this boxes originally.
No difference in construction except one has 2 rows and the other 3 rows.
Red blocks are absolute equal in dimensions and the type of wood used.
The only difference is in the type of wood used for the complete box.
The 2 row box uses play wood on the complete case and sound board.
The rebuilt 3 row box is completely made from massive spruce tree with nut veneer on top.
Sound board is also a massive board of the same thickness as on the 2 row box.
But i don't know the name of the wood type for sure.
The tuning of the boxes is done in the same way.

I never rebuilt the bellows until jet, i just stitch the bellows from one box to the other.

Workman ship is quite poor especially on the 3 row Instrument.
Not much car ware taken to make it look nice inside.
Before rebuilding the 3 row box the box sounded very poor.
Still it had a lot of signs of hard usage so it must have bin a good box other vice it wold not have been in use so much.
Many gluing connection just lost there secure connections over time.

Now both boxes sound very similar sure not completely equal.
The 3 row box seems have a little more sustain in sound as the 2 row box.

My conclusion:

Reeds make the biggest difference but have to be lately seen in combination with the complete box.
Bad design cant be fixed with better reeds. It is some sort of marriage reeds and design.
The absolute main factors.

Material too but much less of influence as i did think for years.

Also some privies experiences do prove the same to me.

Before this rebuilding job i made an other experiment with an old 3 row box.
This 3 row box is even older and i had rebuilt or fixed the mechanic and the bellows years ago.
Still i was never satisfied with the sound so it was nice looking but not in use much.

Replacing the reeds changed the treble side dramatically but not to the better at all.
Replacing the soundboard on the treble side made a change in talk reaction on the higher notes.
The thickness of the sound board was 8 mm in the fist place now it is 0,5 mm and the material was first massive nut wood.
Now it is glass fiber. Sound color is not noticeable change except on the upper higher notes.

Still the treble side is now quite usable, to change it to the better i will rebuild the reed blocks with different dimensions as soon as i find time.

But the bass was very dull without higher overtones.
So i did a major rebuild on the bass side as well.

I only kept the outside frame.
All inside on the buss side was rebuilt with new spruce tree and little other wood in the same way and with the same dimensions as before. The same reeds ware used again.

Result: Buss change somewhat to the better.
Now there is more sustain and a lot more of higher overtones are present.
But the the main character in bass sound remained as it was before.
The lower formatters of the sound did stay as the ware with the old wood.

So it looks like braking in and aging removes higher overtones, But changes nothing on the main sound formation given by construction and dimensions.

And it looks a new box always will sound different and brighter as an old one.
Some people don't like the sustaining ending sound of the buss side of modern helicon boxes shortly after a valve is closed.
Traditional construction on the bass side reduce this but the main difference makes the aging of a box.

Dimensions changes on the chamber has the biggest effect on sound formation in the frequency rang comparable to or human voice.
Box size seems to influence the sound formation in the very low regions around 100 Hz but this is to prove a bit better.
I think also that the relation of the case length to width could be of interest to.

So if one copy's a box exactly with its dimensions exactly as the original and he uses nearly equal reeds and the same tuning the possibility is very high to end up with a sound very similar but sure with a bit more of higher overtones as the older box.

Boxes from a series of the same production sound usual nearly the same because the use absolute the same dimensions and in most cases the same material. Still not one box is exact the same as the other, so from where come the little differences?
This is hard to tell because very little differences remain, the tuning of the reeds is never absolute the same to.
I was tolled at MŁller the biggest Austrian production for diatonic boxes:
The person making the final check on a box usual can tell who did the major work on the box without know who was it. Each box has to some extant sings of the builder in respect of how the keyboard action works and how the sound is.

There would be more on comparing sound formations from my side.
More comparing of different box sizes.

I made test with empty boxes made of different wood.

Most of my tests are in respect of bass chambers (cavity),

and some are on treble chambers.

On the mounting of the reed.

And naturally on the reed it self.

All in all, it is very hard to give exact direction what has to change to change the sound in a other direction.
All is very complex and nearly impossible to but it on a scientific level.

best regards, Johann

#14 Dana Johnson

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Posted 25 August 2006 - 07:10 PM

Regarding Concertina chamber design, I found on my own instruments that irrespective of response, after a certain point, a shallow chamber gave the impression of a small instrument when played. I don't know what to ascribe this to, except perhaps a decrease in strength of the fundamental. I ended up adjusting my chamber depth on the left side by a 1/32" to get the sound I wanted, and found that that small an amount had a noticeable effect on tone character.

I don't know how any of this plays out in diatonic accordion design. The nature of the reed contact and the orientation to the larger surfaces of wood are dramatically different. I once did some experiments with accordion reeds in accordion reed type chambers, and did find that denser / harder materials provided clearer brighter tone.

The reeds themselves certainly can affect the tone character. The reed motion curve both with the air flow and against the airflow and how the reed effects the air flow as it moves is a big factor in the starting point of the tone character. What gets supported and what gets diminished is out of the reed's control. A reed with a lot of tip motion compared to the main body of the reed will likely have a different tone character since the resident time in the restricted zone of the reed window is less for what I would guess would be a steeper sided wave form, more rich in odd numbered harmonics, but for traditional concertinas at least, My experience has been that the character follows the box not the reed. This may be completely different for accordions.

I recently tried out reed pans and action pans made from bigleaf maple, which is a excellent tone wood for violin family instruments, and closer to the light but hard european maple varieties used for centuries in the violin making trade. The result was a raucus, loud but terribly harsh and coarse sounding instrument (that still had the same overall tone character of my other instruments. I first replaced the reed pans with my normal rock maple, with a good deal of improvement , and then re made the action pans in the rock maple as well, and was back to the clear, clean and singing tone I like so much. Conclusion? Concertinas are not violins, that is for sure! Also that since the dimensions were the same, the character was connected with that not the reeds or the wood. I had two differently made sets of reeds as well to swap, and while the tone quality was slightly different , the character was unchanged.

#15 Johann

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Posted 26 August 2006 - 04:33 AM

Regarding Concertina chamber design, I found on my own instruments that irrespective of response, after a certain point, a shallow chamber gave the impression of a small instrument when played. I don't know what to ascribe this to, except perhaps a decrease in strength of the fundamental. I ended up adjusting my chamber depth on the left side by a 1/32" to get the sound I wanted, and found that that small an amount had a noticeable effect on tone character.


Increasing camber cavity volume has an effect on tone color changing toward lower color is may observation.
sure this is a very short and uncompleted answer, and i tend to go conform with your explanation.

I don't know how any of this plays out in diatonic accordion design. The nature of the reed contact and the orientation to the larger surfaces of wood are dramatically different. I once did some experiments with accordion reeds in accordion reed type chambers, and did find that denser / harder materials provided clearer brighter tone.

Sure it is a lot more noticeable on Concertinas, one factor is the single reed construction.
Sam of my instruments do have registers to switch of some reed sets.
And defiantly there is a difference if the one uses reed blocks instead of reed panes.

in respect of materials for reed chambers on reed blocks the is not so much notable difference as if the reed are mounted flat on the reed pan. still i tend to see it as you harder materials enforce higher brighter overtone partials.
I used balser wood in combination with a hard top for the chamber and the result is a sound that is very much liked on the treble side for me, spruce tree wood for the chamber is usual preferred and gives a bit more on brightness and volume. Still the difference in sound depending on the wood used just for the chamber (top and foot excluded ) on reed blocks on accordions do NOT make a big difference. Also for the top usual a midrange hard to soft wood (Alnusincana) is preferred on Austrian and traditional diatonic boxes.

The reeds themselves certainly can affect the tone character.

Very much and is the main Factor.

The reed motion curve both with the air flow and against the airflow and how the reed effects the air flow as it moves is a big factor in the starting point of the tone character.

Yes go conform, still not the bigest contributing factor.

What gets supported and what gets diminished is out of the reed's control.

Right, see it the same way.

A reed with a lot of tip motion compared to the main body of the reed will likely have a different tone character since the resident time in the restricted zone of the reed window is less for what I would guess would be a steeper sided wave form, more rich in odd numbered harmonics, but for traditional concertinas at least, My experience has been that the character follows the box not the reed. This may be completely different for accordions.


This fits very well with my observation, only the explanation why odd and higher harmonies are more present is because different reed dimensions and shape as you describe tend to produce more higher (odd overtones) higher mode Frequency's as discussed with Tom on the RMS goop. In meantime i had email exchange with the IFM in Zwota Mr. Gunter Ziegenhals and he pointed out a Study the made about 20 years ago where the already came to the same conclusion as i did think have discovered the first time.
I hope to get in direct contact to the person (MŁller U. ) who did the stud's in the past.The written document is 3 pages long and is tittled:

*FEM - ein Rechnerverfahren zur Optimierung von Tonzungenprofilen
*Instrumentenbau-Zeitschrift 44 (1990) 9, S. 34, 36, 38 (3 Seiten), MŁller U.

I recently tried out reed pans and action pans made from bigleaf maple, which is a excellent tone wood for violin family instruments, and closer to the light but hard european maple varieties used for centuries in the violin making trade. The result was a raucus, loud but terribly harsh and coarse sounding instrument (that still had the same overall tone character of my other instruments. I first replaced the reed pans with my normal rock maple, with a good deal of improvement , and then re made the action pans in the rock maple as well, and was back to the clear, clean and singing tone I like so much. Conclusion? Concertinas are not violins, that is for sure! Also that since the dimensions were the same, the character was connected with that not the reeds or the wood. I had two differently made sets of reeds as well to swap, and while the tone quality was slightly different , the character was unchanged.

Interesting, sure this must be more noticeable on Concertinas as on diatonic boxes.
Still i think there is a large potentiol of tailoring the sound of reed istruments. And the type of wood used on varies parts of the instrument can surly influence the final acoustic sound heard by the human. The original tests cared out and often quoted to show that the material used for the case of Accordions is of less interest have to be re checked too. Sure the case of the box is not so much contributing as the the reed pan or action board on a concertina or the reed blocks of an accordion still worth to think about.

And it well may be that light soft and stable ply wood as used in most cases for accordion boxes is a good alternative to massive traditional spruce wood. Than all is also much a question of taste, i like boxes witch are built with massive spruce tree even i cant her a lot of difference if the box is made by cheaper ply wood. My boxes built with pear wood sound also quite good to me but the are a little bit different especially for the basses. Is hard to tell how much lately comes from the wood used for the case.Still i tend to think there is a formating influence moved a bit up in the spectrum of sound if harder wood types are used. Spectrum analysis of all my boxes show differences but it is not possible to tell from where the differences come by looking on the spectrum diagrams.
It still is much more guessing as knowing from my few point.

Johann

#16 Frank Edgley

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Posted 27 August 2006 - 01:53 PM

Great discussion. There is certainly a lot to think about, here. There are a lot of variables to consider here, not the least of which involve statements made with regards to factors when discussing English-style reeds and how they do or do not apply to Italian-style reeds, and vice versa.

#17 Dana Johnson

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Posted 27 August 2006 - 05:13 PM

Johann, I really appreciate the information on wood and reeds from the accordion point of view. Your experience is well stated and gives us lots to think about. Take note everybody, just in case any one thought free reed instruments were a simple undertaking! Always good to get an issue looked at from different angles.
Dana

#18 ttonon

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Posted 28 August 2006 - 11:50 AM

Hi Dana,

Thanks for your explanations and descriptions of experiments you have done, and itís this kind of work that keep us thinking. I refer especially to when you changed the material of the reed pan and action board wood from Bigleaf Maple to Rock Maple, keeping all dimensions the same. You appear quite sure that this change of material had a very noticeable effect on musical tone, and I find this result quite interesting, even surprising. Iíd like to explore it a bit further from a theoretical point of view, and thinking about it from my own limited knowledge of acoustics, if it is indeed true that the tone was changed considerably, I see no physical reasoning for it. I agree with you that we can hypothesize many possible factors; however, on close scrutiny, I think most of these can be ruled out. For instance, you say:

For those who want some sort of mechanism to explain it all, I currently subscribe to the "wood in contact with reed shoe" as selective filter theory. All the portions of a reed pan and indeed the action pan in contact with it via the sealing gaskets, vibrate more or less when attached to the moving mass of the reed/ reed shoe system. Planar surfaces have many different natural resonance patterns at multitudes of different frequencies. When a reed harmonic comes close to one of these resonances, the wood wants to vibrate in sympathy with the harmonic, and literally steals the energy from the reed. the energy is then is damped out and turned into heat by the wood's natural damping coeficcients and the losses via all the gaskets. The pitch location of the natural resonances of the reed pan etc. determines the relative strengths of the different harmonics each reed is allowed to express. I could go into considerable more detail here, but this isn't the place for it.


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. If you look at the solutions for resonant frequencies (and relatedly, the speed of sound) in metal strings, columns of air, vibrating reeds, vibrating membranes, vibrating plates, etc., itís this ratio by which material effects enter the expressions for modal frequencies Ė the fundamental and all overtones. I find it interesting that that such a complex thing as resonance can have such a simple statement associated with it, but I invite others to verify this simple fact. Thus, if we seek to understand the effect two different woods might have on the acoustical properties of a concertina Ė in so far as resonant behavior is concerned, and of course assuming all other factors (mainly geometrical) being the same, all we need to do is calculate this ratio for both woods, take the ratio of these calculations, then take the square root of that. The result will give us a good idea how resonance effects will shift in frequency. For solid materials, the stiffness property is its Youngís modulus. When we do the above calculation for all woods, we donít find a very large departure from unity. For instance, of 18 hardwoods I have data for (Markís Mechanical Engineering Handbook), the largest ratio (for Basswood) divided by the smallest ratio (for Black Tupelo) yields (after the square root) 1.2. For 14 softwoods, the corresponding largest (Douglas Fir) and smallest (Eastern Hemlock) yields also 1.2. This, to me, indicates that resonant shifts of partials of the musical tones are confined to within about 20 %, for most all woods, and perhaps significantly less than that for the woods normally used in concertina construction.

For a concrete example, letís approximate the reed pan or action board of a concertina by a disk of Basswood of 6 inch diameter and 1/8 inch thick. For this example, the specific dimensions donít matter, nor does it matter that, in reality, there are other components screwed and glued to these pieces. These complications will only change the numbers, and not the point Iím trying to make. For this idealized shape, the fundamental vibrational mode and first few overtones have the following frequencies, 150, 313, 514, 586, 897, etc. Notice that these frequencies are not in whole number ratios to each other. So, if we change the material for instance, to Black Tupelo, its natural frequencies will be changed to 125, 261, 428, 488, 747, etc. Thus, the natural frequencies are changed uniformly. From this, itís true that a change of wood might cause a more favorable or less favorable match with the partials of a single note; however, given the fact that each musical note contains many overtones, which are whole number ratios to each other, it seems highly unlikely that such a uniform shift of unequally spaced natural frequencies of any wooden member of the instrument could alter the tone of many notes in the same way. I see a very complex shift of both more and less favorable matches. A claim that the concertina becomes generally ďbrighterĒ or ďmore mellow,Ē for instance, implies that many notes of the instrument are affected in the same way, which, to me, cannot be explained by such a mechanism.

The one property of wood that I could see having the same effect on many notes is its density. As illustration, and Iím sure you are aware, Russian bayans are generally regarded as having a brighter tone than similar instruments built with Italian (accordion type) reeds, and itís generally assumed that the reason for this has much to do with the fact that the bayan reed tongues are mounted on a monolithic plate (I believe, often Zinc). This plate, because of its greater mass, is able to remain more stationary than the Italian plates during tongue vibration, enabling sharper pressure pulses and thus more (numbers of significant) higher harmonics. As far as I know, this explanation is still in the realm of speculation, but itís a kind of speculation that, to me, has a firm physical basis. On the other hand, until someone does the decisive experiment (if it hasnít been done already), as far as Iím concerned, the theory could be disproven. In any event, at the present time, I wouldnít really argue against this speculation that a change to more dense wood Ė everything else being the same Ė might possibly cause brighter tones. With this reasoning, a concertina with a Lead body might sound the brightest, but of course, this density solution could have rapidly diminishing returns as density increases. But even here, I would like to know more about the amplitude of vibration of the concertina wooden parts. If this amplitude at the reed mounting is, for instance, orders of magnitude less than the part of the tongue vibration thatís key to sound production, the range of wood densities available might for me rule out this possibility as an explanation. Perhaps Johann knows more on experimental work done on this issue.

With regard to your experiment, I need to point out Ė and I think you will agree - that it wasnít really controlled, in the sense that the two concertina versions are not available to be heard simultaneously. (Perhaps you made good quality recordings?) We all seem to agree that we havenít language to speak precisely about tonal qualities, and youíre even talking about changes effected by switching one kind of Maple to another. How much does Youngís modulus and density change among the Maples? (I donít have data for these.) Iím not claiming that your conclusions are incorrect, but if they are correct universally so, I see little physical basis for it, and I donít think anyone here has identified a robust physical explanation, unless perhaps, the densities of these two woods are very different. In any event, it would be nice to have objective measures; e.g., the trace of an oscilloscope, or a frequency spectrum that we can try to translate to the subjective realm. Perhaps your memory of your subjective reaction is very good, but I think youíd agree that itís in the realm of anecdotal reporting which is difficult to translate to another person without some tangible evidence. All I can do now is thank you for your report and file it away for future reference.

When a reed harmonic comes close to one of these resonances, the wood wants to vibrate in sympathy with the harmonic, and literally steals the energy from the reed. the energy is then is damped out and turned into heat by the wood's natural damping coeficcients and the losses via all the gaskets.


It appears that you view wood resonance as destructive to the expression of partials. Yet, if you think wood resonance is a mechanism to alter timbre of the instrument, donít you think that some of this energy would find its way into the air vibration associated with the musical tone? As you know, this is how sympathetic vibrations work in those instruments where sympathetic vibrations are known to be important; e.g., violins. Wood resonance in these latter instruments causes some damping, but in the main, provides a mechanism to amplify and shape musical tone Ė provided of course the impedance match between different parts of the instrument in the line of energy flow is in the right range. (With too much impedance, sound waves are reflected back and donít get outside, and with too little impedance, too much energy is removed from the part upstream of the flow of energy.) This is a subtle point, but it appears to me thereís some contradiction in postulating that wood resonance is only dissipative, yet it is capable of changing the characteristic tone of the instrument to ďraucus, loud but terribly harsh and coarse.Ē

Chamber design seems to be the primary controlling factor here. There are a number of design factors that also have a strong influence on tone, like pad hole location relative to the reedÖ


With regard to the pad hole, from my own investigations on resonance in cavities, if the cavity behaves as a Helmholtz resonator, itís location is probably not that important with regard to resonance. If the cavity behaves as a quarter wave tube, itís location is critical, with regard to its affect on resonance. Relatively simple calculations can be made to see what kind of resonance is or is not present in the cavity. These points and many others are dealt with in detail in an article I wrote in PICA, now available for free downloading at http://www.concertin.../pica/index.htm (Vol. 2, for 2005).

Thanks again for your comments and I look forward to more.

Best regards,
Tom




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