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#1 ttonon

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Posted 08 March 2011 - 06:23 PM

For those interested, the current edition of Physics Today features and article on free reed musical instruments, both Asian and Western. For those who don't receive the magazine, you can read this article for free at: http://ptonline.aip....tml?bypassSSO=1

Best regards,
Tom
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#2 shaunw

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Posted 08 March 2011 - 08:17 PM

Thanks for the link, an interesting article

#3 Ardie

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Posted 09 March 2011 - 10:48 AM

Thanks a lot Tom. Some comments
.
1. James Cuttingham's own text does not comment upon the issue "initiation of the free reed sound" . The "self-sustained oscillation" of the reed of course does not start by itself.Gotthard Richter has described a theoretical model for understanding of the process and Cuttinghams Reference No 5 seemingly deals with this subject with a somewhat different approach but the abstact naturally gives a limited picture.Have You Tom read, or got the full article?

2.Have your read the other references entirely? and/or do you have access to them?

3, Cuttingham himself describes the bending issue like this
"Pitch bending exploits the coupling of harmonica reeds to the vocal tract of the player. Also important is the coupling between the two reeds, one for each direction of airflow, that share a single reed chamber. Significant acoustical studies of pitch bending in the harmonica include early work by Johnston7 and more recent work headed by Millot13 and Henry Bahnson.14 "

And his Figure 4 referring to his Reference No 13 and 14 says

"Normally, the primary reed—the blow reed when the musician blows and the draw reed when the musician draws—is the most active and responsible for the pitch of the note. Nonetheless, the secondary reed always oscillates. © Although coupling to the vocal tract can be used to bend the pitch of a single reed, in the harmonica the bending involves coupling two reeds, and the motion of the secondary reed is significant. The plot here shows the relative displacement of blow and draw reeds as a player executes a draw bend from G to approximately F-sharp. The draw reed sounds initially, but the blow reed takes over as the player continues to draw but changes embouchure. (Panels a and c adapted from ref. 14; panel b includes elements adapted from refs. 13 and 14.)"

"The motion of the secondary reed is significant". This expression is really mysterious to me and does not seem to be concordant with my own experience:
You definitely can bend a note with a harmonica just as well when you totally block the 'blow reed' when bending down on draw ! Therefore I don't understand neither the formulations above nor the presented sound diagram. As we know (!?) a free reed does NOT speak at all but in the "right" air flow direction.If it possibly "vibrates" passively from a reversed air stream that will not induce sound either. The diagram in figure 4 showing first some kind of oscillation by the primary draw reed and later an oscillation by the "secondary" blow reed thus is mystic. Does it show physical (but soundless) oscillation by the "secondary reed" or do I totally misunderstand the situation?
When you bend a note with a concertina/accordion ( which 'can' be done but definitely is not easy) you don't have the similar relation between draw and blow reeds as in the harmonica and particularly not with an Anglo(!) and you still can bend the note likewise ! What you do is stressing the airflow (greater "attack") and manipulate the opening of the "pad". This seems to contradict the importance of "secondary reed" influence.
Therefore I find it hard to understand the formulation "Also important is the coupling between the two reeds, one for each direction of airflow"

It is definitely true however that the harmonica player *can* use the "vocal tract" in various ways to articulate the tone AND modify the bending BUT no doubt the bending itself can be executed by the draw OR the blow reed only. Most harp players find it a lot easier to bend on draw ( for the lower notes)- than on blow ( for the higher notes) .When you practise harmonica bending you can for instance do it by forming a very thin air stream with closed lips and regulate the "attack" of the note and manipulate the position between instrument and mouth.This can hardly involve any kind of influence by the "vocal tract" as a resonator. You can alternatively do it while actively changing the mouth and throat volumes ("swallowing the tongue" or whatever expression is used to describe the technique) and then it IS plausible of course that "vocal tract resonance" is part of the tone forming.

4. I know bending is a speciality of yours Tom.It would be very interesting to know more in detail how your special accordion is constructed. You have already patented it haven't you? so publishing might not be harmful. Would you mind doing so here? or have you done it elsewhere? or can you consider presenting a description in private

5. One thing that puzzles me a little is the difference in bending ease or capacity between harmonica and concertina/accordion. Like I said you *can* bend to some part with the concertina. I may get a lowering of about 40-50 cent but not a half note (or even two half notes) down as with the bluesharp.I find it easier with an Anglo and brass reeds than with a good quality English and my conclusion simply is that the bending capacity is related to the basic pitch stability of the reed itself. You do expect a high quality steel reed to have *great* pitch stability. A peculiar detail here is that when forcing the airflow in the test bench there may be a gradual lowering of pitch in the range 5-20 cent or so and when forcing the airflow even more very suddenly this lowering reaction changes and the pitch is raised (!) some 50 (!) cent.

#4 ttonon

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Posted 09 March 2011 - 02:44 PM

Hi Ardie,

Reference No 5 seemingly deals with this subject with a somewhat different approach but the abstact naturally gives a limited picture.Have You Tom read, or got the full article?

It's an interesting coincidence that I posted the Ricot paper you refer to on this forum, and a few of us had a lengthy discussion on it, along with one of the early papers by Cottingham. You can find the 3-page thread here: http://www.concertin...opic=11818&st=0

Concerning your specific question, the start transient is not really discussed in the Ricot paper.

2.Have your read the other references entirely? and/or do you have access to them?

I have an ongoing project to keep abreast of free reed developments, have read some of these works, and plan to read the others. I have a subscription to access the JASA papers, though I will have to go to my local university library for both the Acta Acust... and Acoustica journals, which I believe are European, and I don't know if there will be an English translation.

...This expression is really mysterious to me and does not seem to be concordant with my own experience:
You definitely can bend a note with a harmonica just as well when you totally block the 'blow reed' when bending down on draw ! Therefore I don't understand neither the formulations above nor the presented sound diagram.

Interesting that you should mention this. I have done the same experiment, with the same results. As you say, take the covers off a harmonica, suck on an appropriate reed slot, and bend the note my changing your oral cavity, while experiment by covering the reed slot of the "non-active" reed. I find that the sound of the bend is not really different whether your finger covers or does not cover the slot. I read Johnston's paper several years ago and find it apparently sound. I thus concluded that the double reed bend is entirely physically possible, but whether the double reed bend or the single reed bend actually appears in practice, to me, is not a settled issue.

The diagram in figure 4 showing first some kind of oscillation by the primary draw reed and later an oscillation by the "secondary" blow reed thus is mystic. Does it show physical (but soundless) oscillation by the "secondary reed" or do I totally misunderstand the situation?

I think you are interpreting the results as intended, which is to claim that the amplitude trace is accompanied by an identifiable sound. I myself have no grounds to question this result. A normally closing reed can indeed function as an opening reed, under the right conditions, and with the presence of a resonator (oral/vocal tract), it’s pitch can theoretically be made to change from its normal sound to the bent sound. If I recall, the musician behind this figure is none other than Steve Levy, and associated with it are videos with X-ray images of his vocal tract movements while playing. I guess one can question whether the average player can do what Steve does. But still, I’m as puzzled as you concerning this effect. One of the fellows that made that image – Antaki – is an interesting person, being kind of a Renaissance man. It appears that his interests have moved on shortly after making this study. Last I heard, I believe, he lived in the Pittsburgh area and thus, it may be able to contact him concerning this effect.

It is definitely true however that the harmonica player *can* use the "vocal tract" in various ways to articulate the tone AND modify the bending BUT no doubt the bending itself can be executed by the draw OR the blow reed only. Most harp players find it a lot easier to bend on draw ( for the lower notes)- than on blow ( for the higher notes).

I’m an amateur harp player and so find it nearly impossible to bend the blow notes. Since you appear knowledgeable in this area, you are no doubt aware that a recent development in harmonicas is valving the reeds, just like in concertinas and accordions. The advantage here is that now any reed can be bent downward in a way that is as easy as it is to bend on the draw notes.

When you practise harmonica bending you can for instance do it by forming a very thin air stream with closed lips and regulate the "attack" of the note and manipulate the position between instrument and mouth.This can hardly involve any kind of influence by the "vocal tract" as a resonator. You can alternatively do it while actively changing the mouth and throat volumes ("swallowing the tongue" or whatever expression is used to describe the technique) and then it IS plausible of course that "vocal tract resonance" is part of the tone forming.

This is an interesting observation – the fact that a resonator may not be necessary for all effects. I think you are referring here to the “over blow,” which allows the player to bend upwards. I think the effect is dependent on the dynamic pressures supplied by jets in the incoming air flow. This is purely an aerodynamic effect. I would, however, reserve the possibility that at least some acoustic coupling is going on with a resonator. Remember, when you whistle, you are incorporating a very small resonator, possibly no smaller than when you over blow into a harp. This observation wonderfully highlights the complexity of acoustic systems.

I know bending is a speciality of yours Tom.It would be very interesting to know more in detail how your special accordion is constructed. You have already patented it haven't you? so publishing might not be harmful. Would you mind doing so here? or have you done it elsewhere? or can you consider presenting a description in private

Since I still have visions of making some day at least a modest salary from this invention, I tend to avoid public discussion on the details. With any new technology, there are, along with patentable ideas, also what we call “trade secrets” or “proprietory knowledge.” One question invariably leads to another, and it took many hours of work and experimentation for me to advance this technology. I hope you can understand and forgive my reluctance.

I should mention that there are links to YouTube videos on my web site. One of those videos, with Kenny Kotwitz is only one of a series of twelve. If you go to the YouTube site, you can access the others in this series, and there you will find some with discussions on pitch bending, not so much from a technical point of view, but from a musician’s point of view.

You do expect a high quality steel reed to have *great* pitch stability. A peculiar detail here is that when forcing the airflow in the test bench there may be a gradual lowering of pitch in the range 5-20 cent or so and when forcing the airflow even more very suddenly this lowering reaction changes and the pitch is raised (!) some 50 (!) cent.

No, I don’t see much merit in the concept of “pitch stability” with any free reed.
I believe the drop in pitch associated with increasing bellows pressure is a feature of all Western-style free reeds, and Cottingham and others have documented this effect in the literature.

Best regards,
Tom

Edited by ttonon, 09 March 2011 - 03:44 PM.


#5 Johann

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Posted 09 March 2011 - 03:29 PM

Hi tom.

As we did discuss the matter some Yeas ago, my viewpoint is some matter is different, but in a hole i do agree, and in the end the result counts!
And a wish you all the best with your patents and Projects.

May be my approach is a different one, The main effect that a pitch and the timbere of a reed in use in a Instrument can be made variable can be described by coupling effect, as we can do this with discrete electronic circuits. Two discrete circuits both with its on resonance frequenters can be coupled and will effect each other in is resonance frequencies. So modeling reeds associated with cavity with electronic filters or with the respective mathematical expressions would be possible. In same special situation resonance would block reeds from speaking at its own first mode, and a higher mode or the reed itself will be more present as the one it is tuned to, this is not the pitch-bend effect! And if you did understand me wrong in this respect may be you do understand me this time.

So to speak with your own words we have different modes of the cavity chamber. And i add we have also different mods of the reed itself, may be you did not discover this until now because usual the modes of the reed may be less of importance or even not noticeable, but under some circumstances we can force a reed to vibrate on a hinger mode by even blocking the fist reed mode at all. This is not possible with every reed, reed geometry matter a lot.

I see that you did adapt to my thinking in respect of different mods concerning the Chamber cavity. I think to remember that you originally did mot take in account other modes beside the Helmholtz cavity resonance. I did point out earlier that there are more as one resonance spot. For me the quarter wave resonance was the most important, and the Helmholz volume resonance was less of importance. My experiments ware manly concentrating on closed pipe with adjustable pipe length. But i did discover that every change in chamber relations did effect timbre of the sound. Even changing a angle of a wall divider would lead to change in timbre. Chamber length, width, volume, ... has an effete on pitch and timbre. Only on very low pitched reeds the reed itself would have noticeably timbre change effects if reed geometry was changed, so it mattes how put weights on the tip for very low reeds are formed. If the reed was tuned to the same pitch with a weight formed a different geometry, timber would be different. Stiffness of the reed tongue was not touched at all.

Johann

#6 Ransom

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Posted 09 March 2011 - 05:17 PM

...This expression is really mysterious to me and does not seem to be concordant with my own experience:
You definitely can bend a note with a harmonica just as well when you totally block the 'blow reed' when bending down on draw ! Therefore I don't understand neither the formulations above nor the presented sound diagram.

Interesting that you should mention this. I have done the same experiment, with the same results. As you say, take the covers off a harmonica, suck on an appropriate reed slot, and bend the note my changing your oral cavity, while experiment by covering the reed slot of the "non-active" reed. I find that the sound of the bend is not really different whether your finger covers or does not cover the slot. I read Johnston's paper several years ago and find it apparently sound. I thus concluded that the double reed bend is entirely physically possible, but whether the double reed bend or the single reed bend actually appears in practice, to me, is not a settled issue.


Hmm. I'm going to have to try this sometime now.

It is definitely true however that the harmonica player *can* use the "vocal tract" in various ways to articulate the tone AND modify the bending BUT no doubt the bending itself can be executed by the draw OR the blow reed only. Most harp players find it a lot easier to bend on draw ( for the lower notes)- than on blow ( for the higher notes).

I’m an amateur harp player and so find it nearly impossible to bend the blow notes. Since you appear knowledgeable in this area, you are no doubt aware that a recent development in harmonicas is valving the reeds, just like in concertinas and accordions. The advantage here is that now any reed can be bent downward in a way that is as easy as it is to bend on the draw notes.


I can get a little bit of blow-bend on the low harps, but I can't make it stick. I'm a little confused by your comment on valving. I have a valved chromatic harmonica, and I can assure you that valving the reeds does not allow "any reed" to be "bent downward" etc. Quite the opposite: any attempts to bend a note cause the note to choke immediately. I have always attributed this to the fact that the valve is covering the slot for the opposite reed, but you say this is inconsistent with your experience in covering a reed slot with your fingers.

Maybe you're not getting a good seal with your fingers?

#7 ttonon

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Posted 09 March 2011 - 06:10 PM

I can get a little bit of blow-bend on the low harps, but I can't make it stick. I'm a little confused by your comment on valving. I have a valved chromatic harmonica, and I can assure you that valving the reeds does not allow "any reed" to be "bent downward" etc. Quite the opposite: any attempts to bend a note cause the note to choke immediately. I have always attributed this to the fact that the valve is covering the slot for the opposite reed, but you say this is inconsistent with your experience in covering a reed slot with your fingers.

Maybe you're not getting a good seal with your fingers?


Hi Ransom,
I have here a Hohner Bluesband harp, key of C, covers off, and with my finger completely covering the draw reed slot, I can bend every blow reed downward. Without my finger covering the slot, I cannot make the bend on any of them. To me, this is an eminently demonstrable feat.

I don’t know where the confusion is. What is the valved chromatic you have? Isn’t it true that those reeds are valved so that you can make the bends? With the normal (unvalved) chromatics – the ones with the shift lever that causes a half tone shift – bends on any reed are very difficult. It’s my understanding the valves are installed to make it easier. But still, “easier” might still be difficult for a novice. Are you an experienced player?

Best regards,
Tom

#8 ttonon

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Posted 09 March 2011 - 06:14 PM

Hi Johann,

It's nice to hear from you again. I do recall that we have some different ways of seeing things, but there's nothing seriously amiss. I hope you're still finding enjoyment in your experiments, and please let me know of anything new.

Best regards,
Tom

#9 Ransom

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Posted 09 March 2011 - 11:07 PM

Hi Ransom,
I have here a Hohner Bluesband harp, key of C, covers off, and with my finger completely covering the draw reed slot, I can bend every blow reed downward. Without my finger covering the slot, I cannot make the bend on any of them. To me, this is an eminently demonstrable feat.



Hi, Tom!
You said you're covering the draw slot, and bending every blow reed. I'm going to proceed on the assumption that you actually meant that you're covering the blow reed slot (on the top of the harp, with the reed inside the harmonica) and bending each of the lowest five draw notes. If this is not exactly what you meant, you should say so immediately.

I've taken the covers off an extra Special 20 in D that I have here, and attempted the feat I described above. I discovered that placing a finger over the blow slot made it easier to get a deeper, cleaner bend. This was a small surprise to me at first. Then I discovered that although I thought I was effectively cutting off the airflow over the blow reed, I actually wasn't getting a good seal with my finger. I was only restricting the airflow, which does help make a better bend. If you effectively seal your finger on the edge of the slot, then an attempt to bend the draw note will choke, just as it would on a chromatic.

I don’t know where the confusion is. What is the valved chromatic you have?


A Hohner Super Chromonica. It has valves, and when they get too much spit on them the middle-octave G sticks like a deuce. =)

Isn’t it true that those reeds are valved so that you can make the bends?


Nope. They're valved so that you're not wasting air through the non-sounding reed. This helps compensate for the extra air you lose in the slide assembly. If you want to make bends, you've got to take the valves off of the blow reeds like Brendan Power does with all of his.

With the normal (unvalved) chromatics – the ones with the shift lever that causes a half tone shift – bends on any reed are very difficult. It’s my understanding the valves are installed to make it easier. But still, “easier” might still be difficult for a novice.


Valves are quite normal for a chromatic. They are the rule, rather than the exception. And they kill the bends. You may be confusing valved chromatic harmonicas with Hohner's relatively new "XB-40" which is a diatonic harp with valves and twice as many reeds. It's the extra reeds that they put in to make bending easier.

Are you an experienced player?


I can bend draw notes, if that's what you mean. As fun as it would be to tell the story of my harmonica life, I think it's time to post.

#10 Ardie

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Posted 10 March 2011 - 12:13 AM

Fascinating development of the bending story...We seem to find both comfirming and contradicting results when doing the same trials ! I don't reply to each one of you, I just repeat and add my own observations:

1.When blocking the blow reed on an unvalved common diatonic 10 hole blues harp ( I use tape not the finger) I can bend on draw just as easy as I can do it normally.
This in my view strongly speaks against the statement:
"Also important is the coupling between the two reeds, one for each direction of airflow, that share a single reed chamber".

2.I don't have any chromatic at the moment but a Hohner "Chordomonica" which is constructed the same way as the "Chromonica" and valved as well.
I can do bends with this on both blow and draw and even easier (!) both ways than with the blues harp.
This also speaks against the "coupling" statements and that the valve would block the bending option

3.We do know (don't we??)that a free reed does NOT sound if air does not flow in the "right" direction.As far as I can see it does not even "vibrate" and even if it would ( a little) that would never produce sound since the vibration would not cause the necessary clipping of the air stream.

4.A side comment: It is sometimes speculated that a free reed with the same ( or harmonically related) fundamental pitch as a sounding reed might execute "sympathetic" oscillations analogous to a string in a harp for instance.Theoretically this is not believable and in practise I can see no sign of it and have not seen any evidence for it.A myth?

5.The mentioned figure 4c in the referrence in Cuttinghams article - if it is correct - possibly shows the transition from G to F# when recording is made outside the instrument. The same audible result we observe by hearing but says absolutely nothing about the possible activity from the "secondary" reed.

I mean this far that the conclusion below inte the article is false according to 1-3(4) above

"in the harmonica the bending involves coupling two reeds, and the motion of the secondary reed is significant. The plot here shows the relative displacement of blow and draw reeds as a player executes a draw bend from G to approximately F-sharp. The draw reed sounds initially, but the blow reed takes over as the player continues to draw but changes embouchure".

#11 Johann

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Posted 10 March 2011 - 07:00 AM

... I do recall that we have some different ways of seeing things, but there's nothing seriously amiss. I hope you're still finding enjoyment in your experiments, and please let me know of anything new.


Thanks for responding Tom.
You are right "there's nothing seriously amiss" as a did say before the result counts.
In general as to the other discussion not every reed will react on bending equally, older reeds or may be reeds in use on blues harps are made with less stiffness, and therefore the force to bend a note is less as on usual modem reeds or may be on Chromatic harps. The mayor two elements oscillating are the mechanical Tongue and the air colomn with tis two elements are coupled more or less strong. Resonance of air column is variable or can be made variable relatively easy. So from my few point also valved reeds can be made to bend in a chromatic harmonica. If it looks like this is not the case then we have to look at other things being different. Reeds on the compared chromatic harmonica may be stiffer, or the effect of bending is much less as with a second reed participating.

Yes i am still experimenting, but my experiments are more on diffident materials and constructions.
I don't but it public any more because the results are in use on new projects.

Best regards, Johann

#12 ttonon

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Posted 10 March 2011 - 09:56 AM

Ransom:

Hi, Tom!
You said you're covering the draw slot, and bending every blow reed. I'm going to proceed on the assumption that you actually meant that you're covering the blow reed slot (on the top of the harp, with the reed inside the harmonica) and bending each of the lowest five draw notes. If this is not exactly what you meant, you should say so immediately.

Hi Ransom, to paraphrase Lewis Carroll, I said what I meant, and I meant what I said :) I thought the issue here was the validity of the hypothesis that a harmonica needs another reed in the chamber in order to be made to pitch bend (in the so-called “normal” way). Even more, the second reed must have a lower pitch than the reed you want to pitch bend. Thus, when you tightly cover a reed slot with your finger or tape, it’s probably safe to say that you eliminated the effect of the reed in that slot. Proponents of the hypothesis, I believe, seem to argue that the difficulty in bending blow notes is due to the fact that, in most of the blow chambers, the other reed, the draw reed, is of higher pitch. Thus, the fact that you can make a VERY easy bend to all the blow reeds by tightly covering the slot of the draw reed proves the hypothesis wrong.

Concerning valves, it’s my impression that valving the small, ten-hole blues variety of harmonicas – not the chromatics with shift levers – is a fairly recent development, and a big reason for doing it is to enable easier, and more numerable pitch bends. It may be that the chromatics have long been valved, and I can see why, because efficient use of air in such large instruments could be an issue. Because of their size and the difficulty in getting your body parts close to the reed of the chromatics, it’s apparently much more difficult to form the appropriate resonant geometries that are required for acoustic coupling and pitch bending. I admit I’m not an expert on harmonicas and harmonica playing, and these are the explanations that come up from my broader experience with free reeds.

Ardie:

3.We do know (don't we??)that a free reed does NOT sound if air does not flow in the "right" direction.As far as I can see it does not even "vibrate" and even if it would ( a little) that would never produce sound since the vibration would not cause the necessary clipping of the air stream.

Hi Ardie, No, we know the opposite. Many researchers have demonstrated that the normally closing free reed can function as an opening reed, under the right circumstances. Those circumstances usually involve the coupling with an air resonator and/or another reed in the same chamber. There are other musical examples of opening reed valves. The lips of a trumpet player, I believe, can often, but not always, be modeled as an opening reed. I think an other example would be a flag waving in a breeze, but most people wouldn’t consider that musical, albeit patriotic.

5.The mentioned figure 4c in the referrence in Cuttinghams article - if it is correct - possibly shows the transition from G to F# when recording is made outside the instrument. The same audible result we observe by hearing but says absolutely nothing about the possible activity from the "secondary" reed.

I mean this far that the conclusion below inte the article is false according to 1-3(4) above

I myself think Cottingham is in error if he is implying that the normal pitchbending in a harmonica requires the coupling between two reeds in the same air chamber. We both have given our experiences here as proof. On the other hand, I don’t think we’ve given sufficient evidence to rule out the possibility for the kind of double-reed pitch bending Cottingham describes in the article, and there is practical evidence for their claim (see below).

Ransom:

Valves are quite normal for a chromatic. They are the rule, rather than the exception. And they kill the bends. You may be confusing valved chromatic harmonicas with Hohner's relatively new "XB-40" which is a diatonic harp with valves and twice as many reeds. It's the extra reeds that they put in to make bending easier.

Your belief that valves kill the bend for chromatics is intriguing. That’s something I’ll have to look into. If you’re right, I have no reasonable explanation.

It’s my understanding that the XB-40 commercially exploits a key idea that we’ve been talking about; i.e., the fact that harmonica pitch bend can involve more than one reed that are coupled in the same chamber. This harmonica adds extra reeds, called “helper reeds” in the chambers, and their purpose is to provide a reed with a pitch below the pitch of the reed you want to pitch bend. It was invented by Rick Epping, who was an employee of Hohner at the time. After his invention and patent, he toured around, working for Hohner, demonstrating the XB-40 and other Hohner products. My guess is that the work of Johnston and Epping may be related, or rather, one may have affected the other. I’ve often wondered how successful this instrument is in the market place. I don’t hear much about it. Apparently it is more complicated, and perhaps even cludgey, as compared to a valved harp. There may, however, be advantages in the sound of the bend. Harmonica players generally believe that a double-reed bend is superior to a single reed bend. I wish someone with more knowledge could chime in here. Perhaps we can invite someone with more knowledge into the discussion. I suppose there’s a question of how much this topic is of interest to Concertina advocates. Let’s see what happens.

#13 Johann

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Posted 10 March 2011 - 10:51 AM

Valves are quite normal for a chromatic. They are the rule, rather than the exception. And they kill the bends. You may be confusing valved chromatic harmonicas with Hohner's relatively new "XB-40" which is a diatonic harp with valves and twice as many reeds. It's the extra reeds that they put in to make bending easier.


My tests shoe that valved reeds can bend the note. U did this tests with Accordion reeds.

1. A second reed in a ditonic accordion also effects the pitch.
2. A second reed nearly the same pitch but in opposite mounting direction without valves will be forced to oscillate that strong that air coping is going on again.
3. The second reed cant be heard on its own pitch because the resulting sound is one pitch or note voiced.

So don't think one is wrong think about it and You will see under certain conditions both is true.

Johann

#14 Ransom

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Posted 10 March 2011 - 11:14 AM

1.When blocking the blow reed on an unvalved common diatonic 10 hole blues harp ( I use tape not the finger) I can bend on draw just as easy as I can do it normally.

I'm starting to want to hear these "bends" we're all talking about.

3.We do know (don't we??)that a free reed does NOT sound if air does not flow in the "right" direction.As far as I can see it does not even "vibrate" and even if it would ( a little) that would never produce sound since the vibration would not cause the necessary clipping of the air stream.

In the process of a nice, deep draw bend you should be able to clearly see the blow reed pass through its slot in a way that would clip the airstream. If you mostly-block the slot with your finger, you will feel the reed coming up and hitting your finger at the bottom of the bend.

5.The mentioned figure 4c in the referrence in Cuttinghams article - if it is correct - possibly shows the transition from G to F# when recording is made outside the instrument. The same audible result we observe by hearing but says absolutely nothing about the possible activity from the "secondary" reed.

Huh? That figure is a graph of the oscillations of the primary and secondary reed.

Hi Ransom, to paraphrase Lewis Carroll, I said what I meant, and I meant what I said :)

Hmmm. I'm going to have to take the covers off again then...

Well! I guess you can get a low blow bend by damping the draw reed! It doesn't give you the feeling in your mouth that you get when you're coupling the reeds on a low draw bend, though. It doesn't feel the same as a regular (high, two-reed) blow bend either. I think we're producing these low blow bends almost entirely through acoustic coupling with the vocal tract.

I wonder if I'm getting an entire half-step down. Remind me to try again with my tuner handy.

I thought the issue here was the validity of the hypothesis that a harmonica needs another reed in the chamber in order to be made to pitch bend (in the so-called “normal” way).

I assert that the bends we are producing here are substantially distinct from the bends that are produced in a harmonica with the covers on. These are not "the normal way"

Even more, the second reed must have a lower pitch than the reed you want to pitch bend. Thus, when you tightly cover a reed slot with your finger or tape, it’s probably safe to say that you eliminated the effect of the reed in that slot. Proponents of the hypothesis, I believe, seem to argue that the difficulty in bending blow notes is due to the fact that, in most of the blow chambers, the other reed, the draw reed, is of higher pitch. Thus, the fact that you can make a VERY easy bend to all the blow reeds by tightly covering the slot of the draw reed proves the hypothesis wrong.

On the contrary, it substantiates the hypothesis: the difficulty in bending blow notes really is due to the fact that in the low chambers, the draw reed is of higher pitch. So suppressing that higher-pitched reed eliminates the difficulty that was due to it.

Concerning valves, it’s my impression that valving the small, ten-hole blues variety of harmonicas – not the chromatics with shift levers – is a fairly recent development,

I believe this is correct.

and a big reason for doing it is to enable easier, and more numerable pitch bends.

I believe this is unlikely.

#15 Ardie

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Posted 10 March 2011 - 02:00 PM

... Thus, the fact that you can make a VERY easy bend to all the blow reeds by tightly covering the slot of the draw reed proves the hypothesis wrong.


Right, but not quite. A minor modification: "Normally" you make draw bends on hole 1-6 and blow bends on hole 7-10. This seems to support the hypothesis of engagement of the 'opposite/secondary' reed if we look at the note distribution of the 10 hole blues harp.
BUT - now comes the tricky part for myself at least:
1) Like I said before I can do the draw bends on hole 1-6 just about as easy when entirely blocking the blow reeds using tape. ( "just about" since without the covers it is trickier and unusual to hit the hole)
2) I can do the blow bends on hole 7-10 when blocking the corresponding draw reeds the same way ( this however is more difficult but I hardly ever us blow bends anyway so I am not so used to it)
3) When blocking the draw reeds on hole 1-6 I can do blow bends fairly easily on these notes which I can't otherwise.

I AM a bit puzzled myself and don't understand the cause of the findings but nevertheless they strongly speak against the "secondary reed involvement hypothesis" as far as I can see


3.We do know (don't we??)that a free reed does NOT sound if air does not flow in the "right" direction.As far as I can see it does not even "vibrate" and even if it would ( a little) that would never produce sound since the vibration would not cause the necessary clipping of the air stream.

Hi Ardie, No, we know the opposite. Many researchers have demonstrated that the normally closing free reed can function as an opening reed, under the right circumstances. Those circumstances usually involve the coupling with an air resonator and/or another reed in the same chamber.


I don't understand a thing! What is the nature of this research and where can it be found? Whatever it is, has it any relevance here?

I myself think Cottingham is in error if he is implying that the normal pitchbending in a harmonica requires the coupling between two reeds in the same air chamber. We both have given our experiences here as proof.


Fine. That IS what is implied in JC:s article is it not? and bending without this "coupling" is not described at all but it obviously can be done. Now - does the coupled bending exist at all??

.. On the other hand, I don’t think we’ve given sufficient evidence to rule out the possibility for the kind of double-reed pitch bending Cottingham describes in the article, and there is practical evidence for their claim (see below)


Is this what you refer to ("below")?

"On the contrary, it substantiates the hypothesis: the difficulty in bending blow notes really is due to the fact that in the low chambers, the draw reed is of higher pitch. So suppressing that higher-pitched reed eliminates the difficulty that was due to it".

Maybe I get you wrong but but I can't see the point. The main thing that happens physically when you block the reeds at the other side is that the loss of air through those reed slots is eliminated.This effect is the only one that comes to my mind that might explain that in my tests the draw bending on hole 1-6 AND the blow bending on the same holes IS facilitated when the opposite reeds and slots are blocked !

.. XB-40.. This harmonica adds extra reeds, called “helper reeds” in the chambers, and their purpose is to provide a reed with a pitch below the pitch of the reed you want to pitch bend... Harmonica players generally believe that a double-reed bend is superior to a single reed bend.


Is the construction described in detail somewhere? What is a "double-reed bend" and "single-reed bend" ?

3.We do know (don't we??)that a free reed does NOT sound if air does not flow in the "right" direction.As far as I can see it does not even "vibrate" and even if it would ( a little) that would never produce sound since the vibration would not cause the necessary clipping of the air stream.

In the process of a nice, deep draw bend you should be able to clearly see the blow reed pass through its slot in a way that would clip the airstream. If you mostly-block the slot with your finger, you will feel the reed coming up and hitting your finger at the bottom of the bend.


I can't see that the blow reed passes through its slot and if it does how can it clip the airstream when pressed away from the slot??
I can't feel the reed coming up either and IF it does "at the bottom of the bend" that indicates that it was only pressed continually away from the slot like I said - and not vibrating - and returns to its resting position slightly above (!) the slot when the air flow ends.

5.The mentioned figure 4c in the referrence in Cuttinghams article - if it is correct - possibly shows the transition from G to F# when recording is made outside the instrument. The same audible result we observe by hearing but says absolutely nothing about the possible activity from the "secondary" reed.

Huh? That figure is a graph of the oscillations of the primary and secondary reed.


How do you know that?? Or do you? It doesn't say in the figure and it doesn't say in the original abstract by Henry T. Bahnson and James F. Antaki where you read:
"The speaking of the reeds, naturally, when producing a bend, and when speaking as an overblow or overdraw is discussed and investigated by simple stopping of the reeds, by videostroboscopic analysis, and by recording vibration of the reeds with displacement gauges".
And how?? in that case can the "secondary reed" (= the F#) be oscillating with the same mechanical amplitude ( and produce the same I assume sound amplitude) as the primary reed while working in the wrong air flow direction which normally can not make any reed speak at all???
I can't come to any other conclusion than that there IS something inherently wrong in this description of the bending mechanism.

#16 Johann

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Posted 11 March 2011 - 12:53 PM

"...as the primary reed while working in the wrong air flow direction which normally can not make any reed speak at all?"
Yes, but coupled as secondary this is possible.

There is more as one way to do bending a note with accordion reeds.
The main thing is that in every case coupling in one or a other way the case.
Coupling can be loose or strong or very strong. In case of very strong coupling we get two possible resonance spots rater near to each other.
Loose coupling will nearly not effect the two different resonating parts, one will be the major and noticeable oscillating part.
Strong coupling will result in more or less frequency shift.
This tree typical coupling situations are continua from on to the next.

Filters can be set up from more as two resonating parts, then we call this band filters.
May be:
1. fist Reed
2. second Reed
3. air colomn

Nothing new and well documented if we would talk about discrete electronic, but the same applies to acoustic.
We use the same funding in discrete electronic. We would not be able to calculate electronic circuits without Helmholtz and other important Inverters from the 18th century. Helmholtz did set up his rules by using acoustic equipment and we use it for electronic circuits today. Mathematic for electronic did get more precise since his days in most cases, way dont use it no the other way round?


Johann

Edited by Johann, 11 March 2011 - 01:06 PM.


#17 ttonon

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Posted 11 March 2011 - 03:14 PM

... Thus, the fact that you can make a VERY easy bend to all the blow reeds by tightly covering the slot of the draw reed proves the hypothesis wrong.



Ardie, I must qualify the quote you made from my writing, if it is be a stand alone statement: Thus, the fact that you can make a VERY easy bend to all the blow reeds by tightly coverning the slot of the draw reed proves the hypothesis wrong, if you allow valving on the harmonica chambers.

This is important.

As I see it, the experiments we do by taking the covers off the instrument and covering the slots, disabling the operation of certain reeds, cannot prove what actually happens in practice, since those reeds are not disabled. Thus, I myself cannot conclude from my experiments what will happen in an unvalved harmonica, simply because a third important factor – the vocal tract of the musician - is an uncontrolled variable. I’m pretty sure that, when I myself, an amateur, do a draw bend on the harp, it’s quite possible that it is indeed a single-reed bend (it doesn’t involve the second reed). But I leave open the possibility that other players may know how to use their vocal tract differently than I do and thus are able to produce a double-reed draw bend.

Best regards,
Tom

#18 Ardie

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Posted 12 March 2011 - 10:13 AM

This is written when the latest post is #17.I try summing it up at this moment from my point of view:

1) Tom and I agree that the importance of the "secondary reed" as it is described in the article by JC may be questioned and it is not supported - but rather contradicted - by our own experiments

2) Our position is based on
2.1) that blow bends can be made with single reeds if the draw reeds are valved or artificially blocked
2.2) that draw bends can be made with single reeds if the blow reeds are valved or artificially blocked

3) Tom ( and others) mean that coupling may take place and the "secondary reed" may come into action by engagement of the vocal tract forming a resonance compartment

4) I still don't understand the theoretical basis for such engagement by the "secondary reed". Tom said:
"Many researchers have demonstrated that the normally closing free reed can function as an opening reed, under the right circumstances. Those circumstances usually involve the coupling with an air resonator and/or another reed in the same chamber"

To possibly accept this I wish to see the documentation of the said research and to find advise how to set up practical tests to demonstrate for myself what actually happens and to try out if something may be relevant for our present problems

5) As long as I haven't got such evidence I remain sceptic that there IS any involvment by the "secondary reed" at all and I wonder if there might be some fundamental misunderstanding messing things up

6) As far as I can understand bending primarily involves a changed influence from the air stream and pressure on the singular reed.
The vocal tract - when acting as a resonator in these cases - only adds tonally to the sound produced by the "primary reed". The assumed involvement by the "secondary reed" I still this far regard as a theoretical construction without practical evidence. There is a considerable tonal difference between bending simply by using overblow or overdraw technique with very tight lips ( as if you just whistle into the harmonica) or a technique opening up the mouth ( "swallowing the tongue method") but I don't yet understand or accept that the later means any involvement (="coupling") of the "secondary" reed.If one looks at the theoretical combination patterns between the "primary" and "secondary" reeds in the same chamber there is no sensible pattern in the note results.How are for example the options explained to do continuous pitch transitions from D-C#-C or B-Bb-A-Ab while the "secondary reed" is completely inactivated??

7) Today I made some additional and more systematic tests with common 10 hole unvalved harps ( C,G,A) which all reacted the same way, only with minor singular deviations. In the attached file are the results for the C harp. Notes in brackets are a bit difficult to manage and generally blow bends are not as easy to make as draw bends. I inactivated draw and blow reeds completely by taping the whole side in each case and the covers were re-assembled in all trials.

Attached Files






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