Tapered Reed Pans

[alex_holden]

Most vintage Englishes and Duets I've examined have tapered reed pans (the low reeds having deeper chambers than the high ones). Anglos are less likely to have this feature, though they do usually have deeper chambers on the left hand pan. My understanding is that this is an innovation that helps to give the instrument a more even response and volume.

 

I was tapering the pans on my latest instrument yesterday and a few questions arose: 1. Who first started doing this and when? 2. How did the vintage makers perform this operation? 3. Why do some high-quality Wheatstone Englishes have non-tapered pans? Are the ones I've seen just too early to have that feature, or did Wheatstone continue to make some models that way after the invention of tapered pans (why?).

 

 

[Geoff Wooff]

It might be hard to  put a date  on the tapered reedpan  debut, what with the lost  years of the Wheatstone Ledgers  and the complete  loss of those from Lachenal & Co. 

 

I've had  several  Model 22's and 24's  through my hands  and the oldest  ones  not only have flat reed  pans but reduced  chamber wall heights... The idea being to increase  pressure(loudness).  These early models date from  1898-ish  and I recall  one   Model 22 that  I  examined  from post 1910  that did  not have  the taper pans  but also  did not have the   very shallow  chambers  either.  An Aeola  from  1907  definately had  tapered  reedpans  but a model 5  of 1925 did not.

 

I think it may depend on the grade of model  whether it came with the  refinement  of a tapered reedpan.  

 

I have the two extremes  currently ;    the 1898  raised metal end  48 treble  with  flat reedpan  and shallow chambers  (  Less than a 1/4") , lots of dynamic range  and the lower octave can  honk  like a saxaphone  or  the  1927 Baritone treble Aeola  where the  reedpan taper is very well worked out to give  as  perfect a volume balance  as possible through the 4 octave range  as if designed for self accompaniment.

Edited December 20, 2018 by Geoff Wooff

[Frank Edgley]

It's possible that it didn't make as much of a difference as originally thought, or perhaps the extra time/expense did not warrant it. It could have been a reason to charge more, and was sold as an "upgrade." Neither Dippers I have owned in the past had them, but then, I have never seen an anglo with this feature, either.

[alex_holden]

21 minutes ago, Geoff Wooff said:

It might be hard to  put a date  on the tapered reedpan  debut, what with the lost  years of the Wheatstone Ledgers  and the complete  loss of those from Lachenal & Co. 

 

I've had  several  Model 22's and 24's  through my hands  and the oldest  ones  not only have flat reed  pans but reduced  chamber wall heights... The idea being to increase  pressure(loudness).  These early models date from  1898-ish  and I recall  one   Model 22 that  I  examined  from post 1910  that did  not have  the taper pans  but also  did not have the   very shallow  chambers  either.  An Aeola  from  1907  definately had  tapered  reedpans  but a model 5  of 1925 did not.

 

I think it may depend on the grade of model  whether it came with the  refinement  of a tapered reedpan.  

 

I have the two extremes  currently ;    the 1898  raised metal end  48 treble  with  flat reedpan  and shallow chambers  (  Less than a 1/4") , lots of dynamic range  and the lower octave can  honk  like a saxaphone  or  the  1927 Baritone treble Aeola  where the  reedpan taper is very well worked out to give  as  perfect a volume balance  as possible through the 4 octave range  as if designed for self accompaniment.

 

I see, that's interesting. It sounds like for certain styles of playing the flat pan may give a more desirable sound and for others the tapered pan may be regarded as a refinement. I have a Wheatstone English in at the moment with raised metal ends and flat 7.5mm deep chambers (from the missing-ledgers years). It has a powerful sound but not as well balanced as some.

[alex_holden]

17 minutes ago, Frank Edgley said:

It's possible that it didn't make as much of a difference as originally thought, or perhaps the extra time/expense did not warrant it. It could have been a reason to charge more, and was sold as an "upgrade." Neither Dippers I have owned in the past had them, but then, I have never seen an anglo with this feature, either.

 

It's more complex to do on an Anglo because the keyboard isn't a simple pitch progression from one end to the other. I had to vary the thickness of the base board as well.

[Geoff Wooff]

2 hours ago, alex_holden said:

 

I see, that's interesting. It sounds like for certain styles of playing the flat pan may give a more desirable sound and for others the tapered pan may be regarded as a refinement. I have a Wheatstone English in at the moment with raised metal ends and flat 7.5mm deep chambers (from the missing-ledgers years). It has a powerful sound but not as well balanced as some.

Definately , for that  Alistair Anderson sound  the shallow  chamber walled flat reedpan  is the  way to go  but  it can   appear   less well balanced for chordal playing.  Horses  for courses !....  The variety  of  ways  the physical  box  can   influence  the musical result  is  interesting .

Edited December 20, 2018 by Geoff Wooff

[Dave Leggett]

I think that the reason that some reed pans were 'tapered' was just in order to get as near to an optimum capacity in all of the chambers as possible. The chambers act as small cavity resonators, and though designing them to have the optimum capacity is a 'dark art', (I would suggest that this is an art, guided by experience rather than by science: the science is just too complicated!), making them big enough or particularly, small enough, may be a problem if the reed pan is of uniform depth.

Some high pitched reed pairs (or combination pairs in anglos) require a very small chamber volume (say less than 2cc), whereas lower notes in the same pan, a larger volume (say 5cc or more). It  would, perhaps be difficult to achieve this for higher-pitched reeds in a 'parallel' pan without making the chamber so narrow laterally that there would not be room for the smaller reed-pairs to fit into it side-by-side!

Why some historical instruments have this feature and some not is a matter that can't be resolved by speaking to the makers. The added cost of the feature seems to be a dubious suggestion as the feature is to be seen in some relatively inexpensive makes and models and vice-versa.

 

[alex_holden]

14 minutes ago, Dave Leggett said:

I think that the reason that some reed pans were 'tapered' was just in order to get as near to an optimum capacity in all of the chambers as possible. The chambers act as small cavity resonators, and though designing them to have the optimum capacity is a 'dark art', (I would suggest that this is an art, guided by experience rather than by science: the science is just too complicated!), making them big enough or particularly, small enough, may be a problem if the reed pan is of uniform depth.

Some high pitched reed pairs (or combination pairs in anglos) require a very small chamber volume (say less than 2cc), whereas lower notes in the same pan, a larger volume (say 5cc or more). It  would, perhaps be difficult to achieve this for higher-pitched reeds in a 'parallel' pan without making the chamber so narrow laterally that there would not be room for the smaller reed-pairs to fit into it side-by-side!

Why some historical instruments have this feature and some not is a matter that can't be resolved by speaking to the makers. The added cost of the feature seems to be a dubious suggestion as the feature is to be seen in some relatively inexpensive makes and models and vice-versa.

 

 

I was told by an expert off-forum that for Englishes and Duets they made the pans sloped or flat depending on the type of sound the customer wanted. Flat pans tend to have a loud reedy tone across the range, whereas sloped ones tend to progressively give you a fuller, rounder tone to the lower notes. The latter being better suited to players who made their own accompaniment. Apparently Anglo pans rarely had any slope.

 

The production method he described sounds like sloped pans were only slightly more work. Basically, they used a horizontal milling machine to flatten the tops of the walls after gluing them in. If you put a wedge-shaped board between the pan and the milling machine table, that produces a sloped pan instead of a flat one.

Edited December 27, 2018 by alex_holden

[Don Taylor]

 

Is the bottom of the reed pan lowered or the top of the reed pan raised in order get the taper?

 

Don.

[alex_holden]

1 minute ago, Don Taylor said:

Is the bottom of the reed pan lowered or the top of the reed pan raised in order get the taper?

 

Umm, yes? Sort of. Actually you're raising one side of the bottom up off the table of the milling machine, then you pass the cutter back and forth across the top of the pan, and that cuts one side of the pan lower than the other.

 

The way I do it is similar except I'm holding the pan flat to the table and using a CNC operation to progressively lower the cutter as it passes across the top of the pan.

[Don Taylor]

I must be getting confused, but would the pad board also have to be shaped to fit the now no longer flat reed pan?

[alex_holden]

No, the top and bottom surfaces of the pan are both flat but not parallel to each other. The corner support blocks in the bellows frames end up at varying distances from the bottom of the action board.

[RAc]

20 minutes ago, alex_holden said:

No, the top and bottom surfaces of the pan are both flat but not parallel to each other. The corner support blocks in the bellows frames end up at varying distances from the bottom of the action board.

 

This of course leaves the question open how you manage to keep the short ends of the chamber walls perpendicular to the inside of the action box. Did you already saw them tilted to make up for the slope, or do you rely on the chamois gaskets to even out the triangular openings at the end of the chamber walls?

 

Thinking about it again, you probably made the chamber walls a little larger so that you can cut out the slopes, but isn't that really fiddly work?

Edited December 28, 2018 by RAc

[Geoff Wooff]

4 minutes ago, RAc said:

 

This of course leaves the question open how you manage to keep the short ends of the chamber walls perpendicular to the inside of the action box. Did you already saw them tilted to make up for the slope, or do you rely on the chamois gaskets to even out the triangular openings at the end of the chamber walls?

 

Thinking about it again, you probably made the chamber walls a little larger so that you can cut out the slopes, but isn't that really fiddly work?

Nice question Rudiger  !

 

I'm sure  Alex will  have  a great explaination  but  old instruments have   the ends of the walls angled  somewhat  to compensate  and the chamois  gasket  does the rest... usually.

[alex_holden]

11 minutes ago, RAc said:

 

This of course leaves the question open how you manage to keep the short ends of the chamber walls perpendicular to the inside of the action box. Did you already saw them tilted to make up for the slope, or do you rely on the chamois gaskets to even out the triangular openings at the end of the chamber walls?

 

Thinking about it again, you probably made the chamber walls a little larger so that you can cut out the slopes, but isn't that really fiddly work?

 

You just make all the walls and dividers and the central doughnut the same depth, slightly deeper than the deepest chambers of the finished pan, then you mill away the excess. The milling machine removes not very much material at the deep end and several mm at the shallow end. You need to do this in several passes to avoid splintering the walls. The chamois isn't having to work any harder on the dividers because the tops of the dividers end up part of the same flat surface as the tops of the walls.

 

The other thing to think about is how you bevel the edges of the pan to mate with the tapered walls of the bellows frames.

[RAc]

28 minutes ago, alex_holden said:

 

You just make all the walls and dividers and the central doughnut the same depth, slightly deeper than the deepest chambers of the finished pan, then you mill away the excess. The milling machine removes not very much material at the deep end and several mm at the shallow end. You need to do this in several passes to avoid splintering the walls. The chamois isn't having to work any harder on the dividers because the tops of the dividers end up part of the same flat surface as the tops of the walls.

 

The other thing to think about is how you bevel the edges of the pan to mate with the tapered walls of the bellows frames.

 

Thanks Alex - I thought that much, but I'm more curious about the short sides of the chamber walls (the ones that align with the action pan as long as there is no slope in the assembly). Geometry stipulates that when you mill a slope into the entire top of the assembly, some of the short side ends (namely the ones affected by the slope) will not be perpendicular to the sides anymore. Geoff's explanation provides yet another way to solve the issue, so I'd be curious as to what your solution is.

 

I also meant to ask about the related second issue you mention(the reed plate base which now doesn't fit into the bellows frame anymore once it's not parallel to the top anymore). I guess the offset is small enough for the gaskets to make up for the orifices, but knowing you I suspect there is another ingenious solution lurking in the back? ?

 

Edited December 28, 2018 by RAc

[alex_holden]

1 hour ago, RAc said:

Thanks Alex - I thought that much, but I'm more curious about the short sides of the chamber walls (the ones that align with the action pan as long as there is no slope in the assembly). Geometry stipulates that when you mill a slope into the entire top of the assembly, some of the short side ends (namely the ones affected by the slope) will not be perpendicular to the sides anymore. Geoff's explanation provides yet another way to solve the issue, so I'd be curious as to what your solution is.

 

I suspect I'm failing to understand the question. Does this drawing help? Tilting the pan and then milling the top flat automatically gives the tops of the walls the correct angles to fit flat against the action board.

 

 

1 hour ago, RAc said:

I also meant to ask about the related second issue you mention(the reed plate base which now doesn't fit into the bellows frame anymore once it's not parallel to the top anymore). I guess the offset is small enough for the gaskets to make up for the orifices, but knowing you I suspect there is another ingenious solution lurking in the back? ?

 

 

The obvious way to taper the edges of the pan is to use a large disc or vertical belt sander with the table tilted away from the abrasive surface at the appropriate angle, then put the reed pan on the table bottom-down. The problem is if it's a sloped reed pan, the sides have different angles relative to the bottom. The way around the problem is to turn the reed pan upside down so you're referencing off the tops of the walls and tilt the table towards the disc instead. Unfortunately most disc sander tables won't tilt much if at all in that direction, so you have to either modify the table or make a wedge-shaped board and put that between the table and the reed pan.

Edited December 28, 2018 by alex_holden
clarification

[RAc]

I'm thinking about the now not fitting  areas marked with red circles in the last sketch. The blue rectangles depict the action box walls. Since this is a radial reed pan, there are also some chamber walls that will run parallel to the slope, meaning that the ends of those walls will also not be perpendicular to the action box sides anymore, no?

 

Edit: I just saw your response re: belt sander working on the upside down pan. That basically answers my question but assumes you already over-dimensioned the pan at design time so you can get the snug fit back in after sanding. Of course you would do that... brilliant. Thanks!

 

 

Edited December 28, 2018 by RAc