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Reed Generated Vibrations Path Of Travel Through A Concertina.

Reeds Vibrations Materials End plates Direction

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#19 David Hornett

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Posted 24 October 2016 - 05:08 AM

I have read this too, in reference to the later Wheatsons, BUT I have never tried it. Some instruments have square chambers, e.g. Jeffries, Jones, some tapered, Lachenal and Wheatson. In an Anglo ,most chambers, push and pull will be a full tone (note) apart on the same chamber, if what we have read is correct, then I would expect some disharmony, and yet one can tune a reed out of an instrument and be within 10 cents, or better, when it's placed into it?? Or am I up yet another tree.

 

Personally I think chambers are of the size required to take the reed, with  30 reeds and often more in a instrument, there is not much space left to play with to 'tune chambers'.

 

David



#20 Geoff Wooff

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Posted 24 October 2016 - 06:25 AM

One thing I have  noticed  with regard to  all this:

 

With most  concertinas  the reeds will  need to be tuned somewhat sharp  on my tuning jig...   usually this will average  about 11cents,  to play  'in tune'  when replaced  in the instrument.  As if the  chambers  impart  or subtract  some speed from the reeds...  Due to the mass  of materials connected to the  frames.... ?  I don't really know, BUT,  with the very finest  concertinas  I  have  had the oportunity  to  work on  this differential  is   often much less  than that 11 cents  figure... sometimes  as close as   zero.

 

Does this suggest that the  sizing of the  chambers  could have been  optimized  for efficiency ?



#21 David Hornett

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Posted 24 October 2016 - 05:12 PM

Hmm, interesting. With the reeds I make what they read on the jig they tend to read within a few cents in the instrument, but it was suggested to me this is because i have not been accurate enough with the reed clearances in the shoes. I note that the Lachenals I have tuned tend to vary about 5 cents, the bass flat; the treble sharp, so 10-15 cents overall. Someone else suggested to me that the nature of the hole in the tuning jig has an effect on pitch due to tunnelling of the airflow???? I have been too lazy to check this out. But if this is so the out of instrument pit will vary between tuning jigs.

 

David



#22 Chris Ghent

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Posted 24 October 2016 - 06:20 PM

If I get much difference between a reed in and out of the concertina I change the valve.

#23 BW77

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Posted 26 October 2016 - 07:39 AM

I read somewhere that you can remove all the reeds, reassemble the instrument, play it, and even with all the reeds removed hear the approximate pitches from the air rushing through the tuned chambers.

1) Is this true?

If so, wouldn't this indicate that the chambers are finely tuned to the reed's pitch? Original "old pitch"!!!

Is this for tuning reed volumes through resonance?

2) Or... are the reed chambers sized only to influence the responsiveness?

John

Questions above indicated by 1) and 2)

 

1) No !  - I have always wondered where this strange idea originally comes from... One way to find out of course is to try it in real :-)...

Takes a little time but the result ought to be convincing....

 

2) No  - this also comes up now and then. The reed chambers are necessary if you want a double action instrument, i e one which works both on push and pull. With a single action instrument - like common single action basses - you don't need any reed chambers, nor valves. The chambers are usually made as small as possible, just to offer enough physical space for the reed and its swinging amplitude but response is influenced by chamber size. For instance early englishes had no  chamber partitions or just for the top notes, Some time ( late 19th century..somebody certainly knows better when...) partitions were introduced for all chambers and on old instruments people started having cork partitions added for the same reason. If they are removed the ”response” may become a bit slower, the general sound a bit less loud, and the tone a bit ”warmer” or ”less harsh”, likely a result from absorption of higher overtones.



#24 David Hornett

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Posted 27 October 2016 - 01:31 AM

Some accordions / melodians also had their reeds fixed immediately below the pad, without any chamber, these reeds were generally fixed to plates, like a harmonica, and sounded different because the plate transmitted to other of the reeds on the same plate which possibly responded, and the plate did not dampen a discordance at the higher pitch: my guess anyway.

 

As soon as accordions got reeds put into chambers, which allowed them to be taken of the reed plate and given twin shoes, (only two reeds to the shoe) which were about twice as thick as the plate, or even more, the reeds became more mellow, and often louder.

 

There chambers were only sized to meet the reed length, and the opening width of the reed (so it would not hid the side of the chamber when fully open, they also allowed the reeds to be more easily stacked with them having longitudinally into the instrument,  there was no tuning of the chamber.

 

Following this, accordions introduced 'tone chambers', 'the cassotto', on some low and medium reed banks, and rarely on the bass and bassoon reeds. These cassotto chambers made the reeds more mellow, on some of the longer bass reeds it also allowed them to respond faster (?), and moved the instrument from Hitler's derogatory "pig organs", into the classical stream because of the uniform clarity of mellow sound (the 'classical accordion dirge' I think of it as: the liveliness of the folk instrument and vibrato being somewhat dampened).

 

But in all of this, as far as I am aware, there was no tuning of chambers, reed or cassotto, they were just what was required to fit the reed: there simply is not the room in an instrument of about 600 reeds for differing chambers, imagine how long a tuned bass would possibly have to be: thinking of another blow instrument, the low 'D' whistle, may give some idea.

 

But the chamber idea is a good one, find a crystal wine glass and put it to the side of a harmonica while playing. Or do as many do, cup your hands around the instrument (harmonica) and vary the size of the chamber by lifting and lowering your hands.

 

Now this brings me to the concertina, has anyone experimented with a concertina and noticed what difference the cupped hands held either side of the instruments makes: I believe it changes the sound, in the rudimentary experiments I have done it seems to, or is it my imagination? -- the hands form little tone chambers and mellow the sound: so there is something in the chamber idea, but it is not, I believed, used in engineering concertina chambers.

 

david



#25 BW77

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Posted 27 October 2016 - 02:13 AM

 

 

"sounded different because the plate transmitted to other of the reeds on the same plate which possibly responded"

I wonder if that is possible really...*what* do you mean might be transmitted in such case? 

 

"as accordions got reeds put into chambers,.... the reeds became more mellow, and often louder"

Just some terminology nit-picking: The*reed* sound likely does not change but the *tone* outside the chamber/instrument

 

" These cassotto chambers made the reeds more mellow,"

Again....the *reeds* are not affected. The cassotto influence acoustically probably is a combination of "formant resonance" and absorption of higher overtones 

 

 "has anyone experimented with a concertina and noticed what difference the cupped hands held either side of the instruments makes: I believe it changes the sound"

Probably have many such experiments been carried out but reports seem to be few. Concertina maker George Jones is said to have tried  increasing the volume underneath the endplate

to achieve an "organ-like" sound. That probably would work in a similar way as the said accordion cassotto.



#26 Chris Ghent

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Posted 27 October 2016 - 02:16 AM

 

I read somewhere that you can remove all the reeds, reassemble the instrument, play it, and even with all the reeds removed hear the approximate pitches from the air rushing through the tuned chambers.

1) Is this true?

If so, wouldn't this indicate that the chambers are finely tuned to the reed's pitch? Original "old pitch"!!!

Is this for tuning reed volumes through resonance?

2) Or... are the reed chambers sized only to influence the responsiveness?

John

Questions above indicated by 1) and 2)

 

1) No !  - I have always wondered where this strange idea originally comes from... One way to find out of course is to try it in real :-)...

Takes a little time but the result ought to be convincing....

 

2) No  - this also comes up now and then. The reed chambers are necessary if you want a double action instrument, i e one which works both on push and pull. With a single action instrument - like common single action basses - you don't need any reed chambers, nor valves. The chambers are usually made as small as possible, just to offer enough physical space for the reed and its swinging amplitude but response is influenced by chamber size. For instance early englishes had no  chamber partitions or just for the top notes, Some time ( late 19th century..somebody certainly knows better when...) partitions were introduced for all chambers and on old instruments people started having cork partitions added for the same reason. If they are removed the ”response” may become a bit slower, the general sound a bit less loud, and the tone a bit ”warmer” or ”less harsh”, likely a result from absorption of higher overtones.

 

There is a short film somewhere in which Steve Dickinson offers the theory espoused in question 1, and I have seen it written as a quote from him also.  I have no issue with the idea that the sound of rushing wind might step up as the scale goes up but it would be really rough and very stepped. The reason for this happening would not be "tuned" chambers but a natural consequence of chambers being able to be smaller in higher pitches because the reeds are smaller. Some very low notes, in anglos the lowest four notes in a C/G, are often placed in chambers larger than what is physically required to contain the reed, these could perhaps be called tuned. As far as question 2 goes I agree completely, BW, with your list of likely effects created by changing the size of chambers.



#27 David Hornett

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Posted 27 October 2016 - 06:14 AM

Hi BW77, I thought I would run with the efficiency of your approach:

 

"sounded different because the plate transmitted to other of the reeds on the same plate which possibly responded"

I wonder if that is possible really...*what* do you mean might be transmitted in such case? 

 

Maybe incorrect, but reed plated instruments: melodeons, some early german concertinas, of which I have one, harmonicas and bandoneons, are very different in sound to instrument with a single shoe for one or two reeds. Some of this may be due to thickness of the plate, although I once had a bandoneon with very thick plates, some may be to do with the profiling: but I have, and I must admit with no research into the matter, thought the sound to be carried more easily along the metal, allowing it all to speak, and with its rigidity possibly vibrating others of the reeds in short waves along the reed so generating the distinctive sound.  I once owned a maloedion collection, 27 instruments all up made prior to 1939, most had reed plates, and sounded like harmonicas, two had single plates of two reeds per plate, blow and draw: these instruments were in no way different to the others but in this regard sounded like accordions.

 

"as accordions got reeds put into chambers,.... the reeds became more mellow, and often louder"

Just some terminology nit-picking: The*reed* sound likely does not change but the *tone* outside the chamber/instrument:

 

Yes, thank-you.

 

" These cassotto chambers made the reeds more mellow,"

Again....the *reeds* are not affected. The cassotto influence acoustically probably is a combination of "formant resonance" and absorption of higher overtones.

 

There is possibly some debate about this, of the only two people I have ever spoken to about cassotto ('box' in Italian), one argued that the back pressure changed the shape of the reed and thereby changed the sound, the other that the cassotto absorbed the upper partials. The first said a cassotto, was a trial to tune because the reed's pitch changed considerably and unexpectantly when tuned on the bench and replaced in the instrument, and this was due to the 'back pressure'. Malcolm Clapp, although not one of these two tuners, may be able to help here as he'd tunes concertinas and accordians. I have just done a net search and again have come across both explanations.

 

 "has anyone experimented with a concertina and noticed what difference the cupped hands held either side of the instruments makes: I believe it changes the sound"

Probably have many such experiments been carried out but reports seem to be few. Concertina maker George Jones is said to have tried  increasing the volume underneath the endplate. That probably would work in a similar way as the said accordion cassette to achieve an "organ-like" sound..

 

I'm sorry I did not make the point clear, it was: when playing a concertina the hands are shaped like cups around the concertina, so in the few I have made there has been an attempt to accentuate this shape by curving the hand rest to further increase the cupping, and I like to kid myself it has a small effect on the tone by mellowing it.

 

 David.  :)

 



#28 BW77

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Posted 27 October 2016 - 07:34 AM

"sounded different because the plate transmitted to other of the reeds on the same plate which possibly responded"

I wonder if that is possible really...*what* do you mean might be transmitted in such case? 

 

3) ..." I have, and I must admit with no research into the matter, thought the sound to be carried more easily along the metal, allowing it all to speak, and with its rigidity possibly vibrating others of the reeds in short waves along the reed so generating the distinctive sound.

 

4)...." the only two people I have ever spoken to about cassotto one argued that the back pressure changed the shape of the reed and thereby changed the sound, the other that the cassotto absorbed the upper partials."

 

 "has anyone experimented with a concertina and noticed what difference the cupped hands held either side of the instruments makes:

5) I'm sorry I did not make the point clear, it was: when playing a concertina the hands are shaped like cups around the concertina, so in the few I have made there has been an attempt to accentuate this shape by curving the hand rest to further increase the cupping, and I like to kid myself it has a small effect on the tone by mellowing it.

 

 David.  :)

 

 

David, comments on the paragraphs 3,4,5 above

 

3) This idea has been brought forward before also but such effects are hardly present. Despite the common reedplate may *vibrate* it is not likely that this may cause any significant change in the tone production from the active reed and despite some of the other reeds on the same common reed plate may *vibrate* in sympathy with the truly active one since you have no air passage in them a possible humming from them is not expected to influence the audible sound. Maybe it ought to be tested in a lab after all. My guess is that the difference in tone is related to other fctors

 

4) This item however has been thoroughly investigated under lab conditions .The frequency-response of cassottos shows two main features : a) under ca 1000Hz there is an amplification pattern and B)  above ca 1000Hz  a damping pattern. a) likely caused by "formant resonance" related to the size and volume of the cassotto ( similar to what you get with the human throat) B) likely caused by an absorption in the cassotto of high overtones    

"Back pressure" on the reeds is hardly an issue in reality

 

5) Well, everything you put above ( or underneathh...like "baffles"..) covering the outlet of air in the endplates  may have some influence on the tone for sure just as a varying opening area of fretwork has. BUT, you will mostly be surprised how much *sound* that comes from a concertina even if you almost completely cover the outlet of the endplates. The principle with covers ( "verdeck" in german )  has been widely used in accordion production and the effect generally is damping/absorption of higher overtones.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          



#29 BW77

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Posted 27 October 2016 - 08:13 AM

 

 

There is a short film somewhere in which Steve Dickinson offers the theory espoused in question 1, and I have seen it written as a quote from him also.

 

Can you ( or someone else) locate that film "somewhere" or the said quote? I find it all so strange like I said .I have tried it ( being too curious not to...) a couple of times despite spontaneously  rejecting the idea regarding it as a travelling tale. Anyway no such phenomenon can be detected and furthermore even in theory it is contradicted since the reed chamber sizes do not correspond to the wavelength of respective reeds and the progression of chamber sizes does not correspond to the progression of tone frequences either. I have a vague memory that the idea regarding "tuned chambers" may have appeared in some old textbook or encyclopedia too. It may even have been an old marketing gimmick when the partitions of the chambers were introduced. Something för our historians...?



#30 Patrick McMahon

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Posted 27 October 2016 - 11:18 AM

Could be psychological effect. Your brain is used to a certain note coming from a certain button, and "hears" it, even with the reeds out. What your ear hears is just the rush of air, but your brain tries to fill in what's missing.

 

That has been shown to happen in all sorts of ways, so there's no reason that it shouldn't happen when playing an empty concertina.

It's like feeling your toes, even when your leg's been amputated.


Edited by Patrick McMahon, 27 October 2016 - 11:19 AM.


#31 David Hornett

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Posted 27 October 2016 - 06:46 PM

BW77,

 

Thank you for your comments,

 

What most interest me is: Why is there such a difference between reed plates and reed shoes in sound production? The little steel reeded German 'D' instrument with reed plates i have, broke its C5. I used the same tempered steel as I use for my concertinas to make a new one and replaced it, riveting it to the plate. It sounds just like a harmonica reed when played, yet on the bench when I had it in a shoe to profile, it sounded like a concertina reed AND, the shoe I was using had at that stage not been undercut,--  but it was 1mm thicker than the plate???

 

David



#32 Patrick McMahon

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Posted 27 October 2016 - 08:57 PM

BW77,

 

Thank you for your comments,

 

What most interest me is: Why is there such a difference between reed plates and reed shoes in sound production? The little steel reeded German 'D' instrument with reed plates i have, broke its C5. I used the same tempered steel as I use for my concertinas to make a new one and replaced it, riveting it to the plate. It sounds just like a harmonica reed when played, yet on the bench when I had it in a shoe to profile, it sounded like a concertina reed AND, the shoe I was using had at that stage not been undercut,--  but it was 1mm thicker than the plate???

 

David

That's very interesting. Was the shoe brass? Maybe it was the difference in materials that made the difference in sound ??

Or a combination of thickness and material?



#33 David Hornett

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Posted 27 October 2016 - 11:13 PM

Steel reeds, alloy reed plates 2mm, so contrary to what I wrote above the plates are the same thickness as the shoes. Plates nestled on leather and held in place with four elbow screws. The sound board/reed board is 2,2 mm light pine. It is a light, 520 grams, fast little instrument, fairly loud 135 across the flats. Of the type one sees on eBay for $50. Made in Saxony, the poor man's concertina at the turn of last C. Sounds like a harmonica.



#34 BW77

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Posted 28 October 2016 - 12:18 AM

Steel reeds, alloy reed plates 2mm, so contrary to what I wrote above the plates are the same thickness as the shoes. Plates nestled on leather and held in place with four elbow screws. The sound board/reed board is 2,2 mm light pine. It is a light, 520 grams, fast little instrument, fairly loud 135 across the flats. Of the type one sees on eBay for $50. Made in Saxony, the poor man's concertina at the turn of last C. Sounds like a harmonica.

David, I am not sure I completely understand.. the situation You said:

". It sounds just like a harmonica reed when played, yet on the bench when I had it in a shoe to profile, it sounded like a concertina reed "

 

"When played"...was that on the bench again or after reassembly in the instrument ?  that means:

 

did you make the comparison between the sound of your new C5 reed 1) in an individual shoe and 2) in the reed plate ? ....BOTH cases on the bench

OR

did you compare the sound of the new C5 reed 1) in an individual shoe on the bench with 3) in the reed plate but after putting it back in place in the instrument and *playing* it there ?



#35 David Hornett

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Posted 28 October 2016 - 01:19 AM

It was tuned on the plate out of the instrument, sounded different there also. The bandoneon I tuned last year was also tuned out of the instrument, then fine tuned within: in both instances the instrument had the harmonica sound, before and after tuning, the sound I associate with tango music, very different to when tango is played on accordion. Sounded like this on youtube:  Astor Piazzolla - Bandoneón



#36 BW77

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Posted 28 October 2016 - 01:20 AM

Could be psychological effect. Your brain is used to a certain note coming from a certain button, and "hears" it, even with the reeds out. What your ear hears is just the rush of air, but your brain tries to fill in what's missing.

 

That has been shown to happen in all sorts of ways, so there's no reason that it shouldn't happen when playing an empty concertina.

It's like feeling your toes, even when your leg's been amputated.

..." like feeling your toes, even when your leg's been amputated"

This phenomenon - "phantom pain "-  is usually not explained as a "psychological effect"  but rather as a physiological/neurological effect from a misinterpretation by the brain of remaining sensory input from the cut-off peripheral nerves. ...There likely is some "psychology" involved as well...

 

After trying it out some times as I said I do wonder however *what* psychology might be involved if you ..."  hear the approximate pitches from the air rushing through the tuned chambers"...

then you would "hear" the notes coming out also when manipulating the buttons without moving the bellows. I definitely do not myself,  but by systematic intentional training maybe you can learn to "play" a silent instrument and "hear" it as well. I might guess that hearsay is involved in the *empty tuned chamber phenomenon"







Also tagged with one or more of these keywords: Reeds, Vibrations, Materials, End plates, Direction

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