Pitch drop on low notes

[varney]

A problem I regularly find with old anglo concertinas is that the low notes will play in tune on normal push and pull, but when one is playing up tempo and pulls suddenly and strongly on these notes they flatten in pitch. I'm sure this has been discussed before but has there been a definitive answer as to why this happens and the best way to remedy it?

 

I'm talking about the very low notes like C/G on the centre row left etc.

Edited May 1, 2012 by varney

[Frank Edgley]

The only way to moderate this is to play the lower notes more moderately. The reeds are more pressure sensitive the lower you go in pitch.

[Chris Ghent]

A problem I regularly find with old anglo concertinas is that the low notes will play in tune on normal push and pull, but when one is playing up tempo and pulls suddenly and strongly on these notes they flatten in pitch. I'm sure this has been discussed before but has there been a definitive answer as to why this happens and the best way to remedy it?

 

I'm talking about the very low notes like C/G on the centre row left etc.

All reeds drop a little under pressure, but more so in low notes. If they are like that to an extent you find uncomfortable then the only remedy would be a new reed tongue made by a very skilled reedmaker.

 

There is an element of compromise in reed lengths and profiles in order to get them to fit inside a box the size of which makes sense. It is especially an issue with parallel chambers on the reed pan, as the low notes with their long reed frames have to face each other across the pan. In order to get them to fit makers often use a shorter reed, exacerbating the problem. This is why the F/E notes are often the least stable on Jeffries concertinas. Although the C is lower it is one step in towards the centre and there is more room.

 

When you shorten a low reed the difference between the heavy end and the thin root has to be exaggerated a little to get the reed to pitch; that is, thinner root, heavier end. The thinned root means the reed is weaker and will be more easily pressured into a pitch drop under load. The heavier end means the reed will be slower.

 

An advantage to shorter low reeds must be pointed out, they are not quite as loud so will be less likely to drown out the treble. And shorter low reeds are not necessarily such an issue in the hands of a skilled reedmaker, try one of the Dippers' smaller concertinas for an example.

 

Chris

Edited May 2, 2012 by Chris Ghent

[Ransom]

This effect is also increased in conditions where the airflow is constricted-- like if you play a low note, pulling air hard, but only press the button down a little bit, to keep the pad right next to the hole.

 

Chris & Frank have identified several other factors at play. I wonder how much of a role airflow plays. I doubt there's anything to be gained from redesigning hole sizes on an existing instrument, but you might check your key travel to see that you're getting enough clearance?

[Geoffrey Crabb]

A problem I regularly find with old anglo concertinas is that the low notes will play in tune on normal push and pull, but when one is playing up tempo and pulls suddenly and strongly on these notes they flatten in pitch. I'm sure this has been discussed before but has there been a definitive answer as to why this happens and the best way to remedy it?

 

I'm talking about the very low notes like C/G on the centre row left etc.

 

I'll avoid getting into discussion on the technicalities as to why this happens but In agreement with Chris, the cause is that the reed tongues are too thin.

The observed effect of these reeds 'blowing flat' may have been evident since manufacture, (low end cheaper models) or as a result of repitching to A440 at some time in the case of instruments made before the adoption of Modern pitch.

The only real remedy is to have new tongues made and fitted to the offending reeds.

 

Geoff

[varney]

Thanks to you all for the helpful advice.

 

I wondered why some bass notes perform perfectly fine and others bend in pitch and had wondered if the valve thickness could play some part in this. I still wonder if it's a contributing factor but can see now that the thinness of the tongue at the clamp end is the main factor.

 

If that's the case wouldn't loading the tip be the obvious solution to create low pitch reeds which maintain their thickness at the clamp end? I often see bass reeds with some type of solder or metal added to the tip for this very purpose.

 

Is this a viable alternative to filing and what material is best for loading the tip? I imagine it's hard to gauge how much material to add to get the desired note, and that filing this added material would be problematic. Anyone had experience of this practice?

 

Michael.

[michael sam wild]

That's helpful, we have been having a discussion on playing down on the lownotes on 'dark side or forbidden territory' on the Anglo on another thread

[Geoffrey Crabb]

All reeds drop a little under pressure, but more so in low notes. If they are like that to an extent you find uncomfortable then the only remedy would be a new reed tongue made by a very skilled reedmaker. There is an element of compromise in reed lengths and profiles in order to get them to fit inside a box the size of which makes sense. It is especially an issue with parallel chambers on the reed pan, as the low notes with their long reed frames have to face each other across the pan. In order to get them to fit makers often use a shorter reed, exacerbating the problem. This is why the F/E notes are often the least stable on Jeffries concertinas. Although the C is lower it is one step in towards the centre and there is more room. When you shorten a low reed the difference between the heavy end and the thin root has to be exaggerated a little to get the reed to pitch; that is, thinner root, heavier end. The thinned root means the reed is weaker and will be more easily pressured into a pitch drop under load. The heavier end means the reed will be slower. An advantage to shorter low reeds must be pointed out, they are not quite as loud so will be less likely to drown out the treble. And shorter low reeds are not necessarily such an issue in the hands of a skilled reedmaker, try one of the Dippers' smaller concertinas for an example. Chris

Thanks to you all for the helpful advice. I wondered why some bass notes perform perfectly fine and others bend in pitch and had wondered if the valve thickness could play some part in this. I still wonder if it's a contributing factor but can see now that the thinness of the tongue at the clamp end is the main factor. If that's the case wouldn't loading the tip be the obvious solution to create low pitch reeds which maintain their thickness at the clamp end? I often see bass reeds with some type of solder or metal added to the tip for this very purpose. Is this a viable alternative to filing and what material is best for loading the tip? I imagine it's hard to gauge how much material to add to get the desired note, and that filing this added material would be problematic. Anyone had experience of this practice? Michael.

Hi Michael, To reitterate what Chris has said, all reeds have an ideal length and flexibilty for a partcular note. Unfortunately it is not possible to conform to this ideal where the internal confines withinin an instrument are dictated by an acceptable external physical size. A compromise has be employed where some shorter or undersize reeds have to be adapted or fashioned to meet a requirement. In many cases this has or is done by adding mass to a section of the upper face of the reed tongue at the tip (loading) to achieve a lower note than the reed was designed to generate. The loading material may be solder directly applied or brass sweated to the tongue. However, profiling must still be carried to the main body of the tongue to obtain the correct flexibility. Although the above may provide a required note value, the tone may be affected, being different from the unloaded reeds in the instrument. Loading is usually carried out if the reed tongue stock available is of one size and a much better solution for the 'low' reeds is to employ a thicker guage tongue material and profile this to obtain the note and flexibilty required. <BR>Geoff Edited May 5, 2012 by Geoffrey Crabb

[Jody Kruskal]

A problem I regularly find with old anglo concertinas is that the low notes will play in tune on normal push and pull, but when one is playing up tempo and pulls suddenly and strongly on these notes they flatten in pitch. I'm sure this has been discussed before but has there been a definitive answer as to why this happens and the best way to remedy it?

 

I'm talking about the very low notes like C/G on the centre row left etc.

 

All the discussion of weighted reeds and how they can vary in pitch under high pressure might explain your problem, but consider my experience and see if the solution I came up with could be helpful. I have an old Jefferies C/G with weighted short reeds for the lowest notes and had the same problem you have, but it sounded to me like in addition to the lowering of pitch there was a constricted buzzy sound to the note that lead me to believe that the reed was being flattened by coming in contact with something to interfere with it's swing, namely the interior bellows edge which was angled in toward the reed pan. I glued several narrow but thick leather spacers (1/2 inch thick or so) to the reed pan on either side of the reed and in a few other convenient places. This prevented the bellows from touching and interfering with the reeds and that seemed to work very well for a few years. The problem returned and I added a bit of thickness to the spacers fixing it again.

[adrian brown]

Jody,

 

Over on this thread, Mark and Chris briefly discussed the odd screw(s) found in the reed pans of some Jeffries anglos. Seems they probably have the same function as your leather spacers?

 

Adrian

[Chris Ghent]

My Jeffries G/D has a partially inserted screw beside the longest reed which serves the same purpose as your leather. I'm not sure if it is a factory screw or an owners mod, but the issue must have been there from the first moment. Your fix is probably kinder to the bellows. This issue is very associated with parallel reedpans, Crabbs and Jeffries and their derivatives; on radial pans the swinging end of the longer reeds would clear the bellows.

 

Chris