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Nasal Sounding 'inboard' Reeds


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Adrian, I think you controlled bellows pressure quite well in the recordings you made. If you compare the traces in Figure 1 of the .doc file I attached above, it's obvious that the the inboard reeds have a much lower amplitude (volume) than the other reeds, and the most obvious guess why this is so probably has something to do with the doubly long aperture length. I'm assuming that the inboard notes you played do not have the chamfered aperture you show a picture of. As I mentioned to Mark, it's difficult to theoretically explain how such a long aperture would affect sound spectrum, but the effect on sound volume is intuitively easier for me to make guesses about. Thus, the apertures in your pictures were perhaps chamfered as an effort to increase sound volume.

 

Tom

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I'm attaching here a file containing some photographs I've taken of various instruments which have the scalloping to the pad holes. I haven't got the recording equipment to enable me to carry out detailed trials but to the ear, I haven't been able to discern any noticeable volume difference from reeds which have the scalloping to those which don't and it's not always consistent as to which of the reeds sound nasal; in the case of the two 39 key C/G instruments, one sounds nasal and the other doesn't but I haven't thoroughly measured to find the differences.

 

As you'll see from the photographs and the notes, there doesn't seem to be a consistent pattern as to which locations have the scalloping although it may be generally true that one is more likely to find the scallops on the larger Jeffries rather than smaller (30 keys or less) Jeffries and instruments from other makers

 

Alex West

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Tom,
Thanks for your reply - yes I see that the inboard notes have much less amplitude, but actually on this concertina, the double length aperture sound hole is chamfered (or scalloped) to quite a large degree. I have made a couple of new recordings of the same modification on a CG instrument (Suttner), where the hole is not chamfered - both with the modification and without. On this instrument the reeds are fitted into dovetail slots, rather than being screwed on as was done on the Jeffries inboard reeds but this seems to make little difference. Again there is a big amplitude difference and the nasal sound is very evident, but on this instrument, I find my blu-tack modification less successful.


Alex,
Thanks for sharing your impressive documentation on this scalloping - I agree that there seems to be very little logic behind these modifications, but note that two of the instruments you've seen, are marked with the R Whitton ink stamp (30 key C Jeffries in C/G and the 50 key Jeffries Bros Duet) which is something Mark pointed out to me. It stuck me too that it is often very neatly done, by somebody who knew how to handle a knife, but sometimes it looks really quite ropey. Have you noticed whether the thumb button notes on CG instruments are systematically worse than on the lower pitched concertinas, and is there any regular difference between press and draw? (On my own instruments I find the higher pitched thumb button reeds (press) worse than the draw. (I don't have a 'drone' configuration on any instrument, to be able to make a useful comparison.)


Adrian

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Alex, it would be interesting to see the counterpart of those pictures you posted pdf of the reed pans. If more internal volume within the chamber was the purpose of removing wood around the holes, was it possible to move the chamber end-wall down a little to make it bigger? Seeing how the wood is scalloped from one direction, a lot of the time, would this have anything to do with manipulating the direction (maybe intensity) of air flow towards a certain part or end of the reed? Just blindly guessing because it is so fascinating to see such a modification. I assume it's not like undercutting the fingerholes in the bore of a wooden flute of uilleann chanter?

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Laurence, Adrian

 

I'll take a look at both of your queries and post later. It may take a little time so bear with me! I don't know whether it's significant that all of the scallops I've seen are to instruments with sycamore action faces. From a quick check on a very limited sample, the mahogany pans are just over 1mm thinner than the sycamore pans and from personal experience, the mahogany is considerably softer than sycamore so I'm sure that will affect the tones.

 

I seem to recall being told or reading here that the mahogany built Jeffries always came with bone buttons and the sycamore built ones always had metal buttons. That's confirmed by teh ones I've seen but I don't know whether this a universal truth and whether this was an option or just a historical accident. Equally, I haven't done any research on the acoustic differences

 

Alex West

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And here's the second file; I should perhaps have said that the red ovals indicate the reed locations where there is scalloping on the corresponding action face. I concur that the scalloping varies in quality (to be pedantic the better ones look like a sharp gouge was used whereas a knife (or a labrador's tooth) was used on the more ragged ones).

 

In response to Adrian, the thumb button isn't universally the most nasal sounding of the reeds on the concertinas I could lay my hands on quickly; in some cases, it's the "inner" reed - the one(s) located on the lowest (4th) row. The C/G does seem to suffer particularly from the nasal quality but the lower pitched boxes I could get to are slightly larger anyway so the reed chamber volume may be that bit bigger anyway. There does seem to be a subtle difference between the draw and the press, but there is so much variability in timbre on the Jeffries that I doubt this is the significant variable.

 

I have noticed in the past that Wheatstone anglos have much less of the timbre variability and "nasality" and that's certainly true of the quick test I just did; the Wheatstone C/G with a radial reed pattern is much more consistent in tone across all the reeds.

 

In some ways, the tone variability is what gives the Jeffries its character and appeal - but perhaps not so much that it's difficult to bear playing it!

 

Alex West

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Alex, thanks for the additional info and photos. It does see quite a random modification and I can't see any underlying trend concerning which holes were scalloped. However it does seem that a good proportion of the holes for the inboard reeds were scalloped. I'd agree with you that Wheatstones with their radial chambers do seem to be more even in tone, but I can't understand why an inboard reed should have such a different tonal characteristics, from the same reed mounted towards the outside of the reed pan. I also note than while we all seem to understand the tone qualities implied by the term 'nasal sound', there doesn't seem to be any technical explanation about the harmonic 'architecture' that would produces a nasal sound.

 

Adrian

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  • 2 weeks later...

Last weekend, I had a go at cutting away the action plate of my CG Suttner to see what the effect a cut-away would have. I've put a few photos in a .pdf document here to show the process. This followed a private correspondence with another player here whose GD Jeffries apparently has the same sort of cut-away, presumably as a later modification. Anyway my efforts were happily rewarded by a great improvement to both thumb button notes, The notes are louder, the nasal sound is practically gone and there is little perceptible difference between the thumb pull c and the normal push c, or the thumb (push) f and the normal pull f. I've made a third sound file here with both the cut away modification and the blu-tack. (My earlier recordings of these notes without the blu-tack and with, before I made the cut-away are here: with/without)
The only downside is that now, as Alex remarked, the e/eflat '4th' row button (the other button with 'inboard' reeds) is the most nasal sounding...
As I said in an earlier post, I wouldn't feel happy doing this on an old instrument, but might be worth taking into consideration in designing new instruments.

Adrian

 

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I can't understand why an inboard reed should have such a different tonal characteristics, from the same reed mounted towards the outside of the reed pan. I also note than while we all seem to understand the tone qualities implied by the term 'nasal sound', there doesn't seem to be any technical explanation about the harmonic 'architecture' that would produces a nasal sound.

What effect does it have on tone if a shoe is forced into the slot too hard? Too soft? Where is the best pressure point between the shoe and the wooden slot?

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What effect does it have on tone if a shoe is forced into the slot too hard? Too soft? Where is the best pressure point between the shoe and the wooden slot?

 

 

Laurence,

 

As I understand it, forcing a reed shoe tightly into its slot is likely to make the reed buzz, as the sides will tend to bind against the tongue, casing a metallic sort of sound. I've had this happen in the past solely as a reaction to high humidity levels, where easing the shoe out of the slot has instantly cured a buzz. If the shoe is too loosely fitted, the shoe will vibrate in the slot and cause a different sort of rattle. As to pressure points, I've heard it is important the clamp end of the frame is well anchored in the reed pan.

 

Hope this helps answer your question, but I'm sure others will have more to add.

 

Adrian

 

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What effect does it have on tone if a shoe is forced into the slot too hard? Too soft? Where is the best pressure point between the shoe and the wooden slot?

 

 

Laurence,

 

As I understand it, forcing a reed shoe tightly into its slot is likely to make the reed buzz, as the sides will tend to bind against the tongue, casing a metallic sort of sound. I've had this happen in the past solely as a reaction to high humidity levels, where easing the shoe out of the slot has instantly cured a buzz. If the shoe is too loosely fitted, the shoe will vibrate in the slot and cause a different sort of rattle. As to pressure points, I've heard it is important the clamp end of the frame is well anchored in the reed pan.

 

Hope this helps answer your question, but I'm sure others will have more to add.

 

Adrian

 

 

Thanks Adrian! That helps. I have what might be a "nasal" sounding reed (or two, or three), but not sure of all the possible explanations and definitions. Pushing a certain note on the first (inner) row sounds clear and bell-like--chirping like it should, but pulling the same note on the second (middle) row sounds totally different...maybe like what's described as nasal...or at least some different kind of vibration (?) to it. It sounds more reedy, more buzzy, or something. Anyway, I don't like it as well. I'm playing an anglo Wheatstone - linota reedpan layout (radial pattern). A while back, I had pulled out the offending reed though, on the middle row, so maybe I pushed it back in too hard? Other than that, the concertina sounds like you'd expect...it has that nice traditional quality sound. Maybe, like yours, the chamber is too big for the reed? For some reason, my player won't open up the sound clips posted here, so I can't compare.

 

Also, I've noticed that some reeds have been shimmed with a thin strip of paper along one edge--between the side of the shoe and one edge of the wooden slot. Wouldn't this interfere with tonal transfer from reed to soundboard, muting it to some degree?

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Laurence,

 

a couple of thoughts...

 

If when you push a reed frame in tightly the reed catches then this is a fault condition rather than anything normal. Yes it might be because of movement of the wood due to humidity changes, but what it means is the frame is being held somewhere in the middle rather than at each end. In an ideal world the frame would be tightly held all around. This is fine with thick reed frames, wider clearances and stable climate. Without these circumstances makers of reeds with finer tolerances often waist the frame. This means if the wood pinches on the frame due to swelling from humidity then it has less chance of pushing the unsupported long side of the frame in on the reed.

 

The pieces of paper lining the slots beside your reed frames are a fix designed to deal with another aspect of humidity change. When a piece of wood shrinks due to losing water any hole in the wood will get bigger. Yes I know it is not intuitive. Reed slots in a reedpan are essentially holes so they get bigger. This means the frames become loose. There are two fixes, take a little off the narrow end of the frame so it fits further into the slot where it will tighten, or pack the sides with something. As it happens paper is a good packing material; it is, if you think about it, wood, and so not so very different to the reedpan. Of these two fixes I would reach for the paper first, taking brass off the frame is a one way step, the concertina may yet become hydrated again, when you move back from Arizona to Ireland for example. It is not as straightforward as that, there is no guarantee the re-hydrated wood would be the same shape as the original, nevertheless the paper is a non intrusive fix. Taking brass off the frame also may bring the reed into contact with the wood at the tip.

 

If you have two notes of the same pitch with a different tone it could be an issue. One may be loose in its slot and losing lower partials, one could have a much more resistant valve, or it may be normal, they could just be naturally different. If they are between B and e on an anglo and therefore on different ends then they are more likely to be different than the same. The reedpans will have different partition depths, one reed could be substantially under your hand, other differences may be possible. Rather than see it as a fault why not try to use it. Also, play it to someone else standing 10 ft away, some things are much more apparent to the player.

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Wouldn't this interfere with tonal transfer from reed to soundboard, muting it to some degree?

Nope. The reedpan is not a soundboard. Many other instruments produce sound by resonating a soundboard that moves the air, but free-reed instruments slice the airstream as it passes through the reed slot.
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Laurence,

 

a couple of thoughts...

 

If when you push a reed frame in tightly the reed catches then this is a fault condition rather than anything normal. Yes it might be because of movement of the wood due to humidity changes, but what it means is the frame is being held somewhere in the middle rather than at each end. In an ideal world the frame would be tightly held all around. This is fine with thick reed frames, wider clearances and stable climate. Without these circumstances makers of reeds with finer tolerances often waist the frame. This means if the wood pinches on the frame due to swelling from humidity then it has less chance of pushing the unsupported long side of the frame in on the reed.

 

The pieces of paper lining the slots beside your reed frames are a fix designed to deal with another aspect of humidity change. When a piece of wood shrinks due to losing water any hole in the wood will get bigger. Yes I know it is not intuitive. Reed slots in a reedpan are essentially holes so they get bigger. This means the frames become loose. There are two fixes, take a little off the narrow end of the frame so it fits further into the slot where it will tighten, or pack the sides with something. As it happens paper is a good packing material; it is, if you think about it, wood, and so not so very different to the reedpan. Of these two fixes I would reach for the paper first, taking brass off the frame is a one way step, the concertina may yet become hydrated again, when you move back from Arizona to Ireland for example. It is not as straightforward as that, there is no guarantee the re-hydrated wood would be the same shape as the original, nevertheless the paper is a non intrusive fix. Taking brass off the frame also may bring the reed into contact with the wood at the tip.

 

If you have two notes of the same pitch with a different tone it could be an issue. One may be loose in its slot and losing lower partials, one could have a much more resistant valve, or it may be normal, they could just be naturally different. If they are between B and e on an anglo and therefore on different ends then they are more likely to be different than the same. The reedpans will have different partition depths, one reed could be substantially under your hand, other differences may be possible. Rather than see it as a fault why not try to use it. Also, play it to someone else standing 10 ft away, some things are much more apparent to the player.

This is good information. Luckily, I live in a dry climate so don't have to worry about wood shrinking or swelling. I've wondered why sycamore was a wood of choice, does it have properties that make it more stable? I think I'll follow your advice and leave the reeds alone, the difference is not alarming. It's the 2 Gs (push) and 2 As (pull), LH, that were different sounding. Thanks so much for posting details about the contact points of the reed frames to the wooden slots. That makes a lot of sense.

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Wouldn't this interfere with tonal transfer from reed to soundboard, muting it to some degree?

Nope. The reedpan is not a soundboard. Many other instruments produce sound by resonating a soundboard that moves the air, but free-reed instruments slice the airstream as it passes through the reed slot.

 

I never knew that! So, it's not like resting a tuning fork on a guitar body to get it to resonate more loudly? Have you ever noticed a reed increasing in volume when you set it down on a piece of wood while it's vibrating?

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I never knew that! So, it's not like resting a tuning fork on a guitar body to get it to resonate more loudly? Have you ever noticed a reed increasing in volume when you set it down on a piece of wood while it's vibrating?

You might be able to observe that effect if you actuate a reed by plucking it, but that's not how a reed operates when it's being played.

 

You may be able to convince yourself of this by biting down on the corner of a harmonica as you blow through the first hole-- the sound doesn't get particularly louder or softer, and the harmonica doesn't vibrate your teeth like a tuning fork would.

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Even though the reed pan is referred to as a soundboard, it doesn't really function as one. Then, the choice of wood (sycamore vs. mahogany, etc.) is mostly for stability purposes and changing moisture/temperature conditions so it doesn't move or crack. I wonder if kevlar or carbon has been experimented with...metals like aluminum would expand and contract too much thus pinching the reed frames during hot weather. Speaking of that, it must be for some other purpose that the shoe touches the wood along the sides of the slots at the toe and the heel, but is left loose in between. I assume then that the tone and volume is produced in the reed chamber and responds according to material used there and on the end plates...perhaps even the shape of the end plates. And here I thought that raised ends were meant for people with short fingers!

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