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david robertson

Crossover Levers

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Hi Adrian, Geoff, and all,

 

It's always a great honor to all readers (present and future) when Geoff takes the time to join these discussions! Thanks Geoff for all the invaluable information and wisdom you share!

 

Just as an addendum to Geoff's contribution, I have seen 20th-century 31-key H. Crabb anglos with a different LH lever arrangement than shown in Geoff's drawing (and I know he has seen those as well). I looked for the forum discussion in which we talked about them, but didn't find that discussion. However, the search retrieved this article in which Geoff is quoted, so I know that he has seen this type of lever design also. Note the lack of overlapping levers and the serpentine curvature of one lever in particular:

 

http://www.concertina.net/mws_inside_a_crabb.html

 

In my opinion, this arrangement of levers (and the entire design of the action and the reedpans) may have been intended as a compromise with these goals in mind:

 

1) Bring up the volume of the notes sounded by the index finger button on the LH inside row (these would be D / E on a typical C/G anglo).

2) (possibly) Avoid crossed levers of the older design, that can lead to interferance when sounding the LH thumb button simultaneously with the top button of the outside row.

 

In my own opinion, goal number 1 may have been most important. In some more common designs for the action of a 31-key anglo, the notes from that D/E button can be muted. Those are the smallest reeds on the left side of a typical 31-key anglo, and they are sometimes situated in a position in which their volume is muted further by the handrail, fretwork design, and player's hand. But the anglos designed like Mark Stayton's H. Crabb (and similar ones that I've seen) have a very bright, clear sound from the D/E button.

 

However, 2) may have been a factor stimulating the layout of these non-overlapping lever designs. I can usually set up the action of a 31-key anglo that has crossed levers to avoid any lever interference, by careful attention to pad heights and damper thicknesses. But my own preferences are for lots of pad lift and lots of button travel, so that when I optimize the action of an old 31-key anglo for the sound and feel that I prefer, I do sometimes get a slight contact of levers when I use the thumb key simultaneously with the G#/Bb key (top button, outside row).

 

PG

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Here's an anglo with crossover levers that I've just noticed on ebay - I assume it was done to avoid an inboard reed for the LH thumb button?

 

Adrian

 

PS: it's here: http://www.ebay.co.uk/itm/Concertina-anglo-90-sure-Crabb-/161619786343?pt=LH_DefaultDomain_3&hash=item25a14a3a67

 

attachicon.gifscreen-capture-14.jpg

 

See attached, I hope it is understandable

attachicon.gifCrossed levers 31 button Crabb Anglo.doc

 

Geoffrey

 

Thanks a lot Geoffrey, that's very clear and understandable

 

Adrian

 

Hi Adrian, Geoff, and all,

 

It's always a great honor to all readers (present and future) when Geoff takes the time to join these discussions! Thanks Geoff for all the invaluable information and wisdom you share!

 

Just as an addendum to Geoff's contribution, I have seen 20th-century 31-key H. Crabb anglos with a different LH lever arrangement than shown in Geoff's drawing (and I know he has seen those as well). I looked for the forum discussion in which we talked about them, but didn't find that discussion. However, the search retrieved this article in which Geoff is quoted, so I know that he has seen this type of lever design also. Note the lack of overlapping levers and the serpentine curvature of one lever in particular:

 

http://www.concertina.net/mws_inside_a_crabb.html

 

In my opinion, this arrangement of levers (and the entire design of the action and the reedpans) may have been intended as a compromise with these goals in mind:

 

1) Bring up the volume of the notes sounded by the index finger button on the LH inside row (these would be D / E on a typical C/G anglo).

2) (possibly) Avoid crossed levers of the older design, that can lead to interferance when sounding the LH thumb button simultaneously with the top button of the outside row.

 

In my own opinion, goal number 1 may have been most important. In some more common designs for the action of a 31-key anglo, the notes from that D/E button can be muted. Those are the smallest reeds on the left side of a typical 31-key anglo, and they are sometimes situated in a position in which their volume is muted further by the handrail, fretwork design, and player's hand. But the anglos designed like Mark Stayton's H. Crabb (and similar ones that I've seen) have a very bright, clear sound from the D/E button.

 

However, 2) may have been a factor stimulating the layout of these non-overlapping lever designs. I can usually set up the action of a 31-key anglo that has crossed levers to avoid any lever interference, by careful attention to pad heights and damper thicknesses. But my own preferences are for lots of pad lift and lots of button travel, so that when I optimize the action of an old 31-key anglo for the sound and feel that I prefer, I do sometimes get a slight contact of levers when I use the thumb key simultaneously with the G#/Bb key (top button, outside row).

 

PG

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On my first concertina, (30 button plus air and drone,) I ran into the short chamber length issue. Rotating the reed pans 60 degrees helped put the long chambers nearer the buttons that needed them, as well as allowing me to avoid any short levers. (My shortest is 1.5 inches ). Fewer pads under the hand was a benefit, though I did have to choose symetrical placements for doubled reeds to keep them sounding the same. The reeds weren't a problem on the right as Geoff says, but the lever lengths were even better on the right side canted the opposite direction.

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On 3/5/2015 at 7:09 PM, JimLucas said:

 

I don't believe I've ever seen blank/empty segments in any concertina with radially arranged reed chambers, though I suppose this could be the first. :unsure:

 

I have a Crabb 48 button Crane with a large empty chamber on the bass side.

 

LJ

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I have just looked inside my 56 button single acting bass to see if there are any crossed levers.

 

There is a beauty on one side (a less spectacular one on the other): picture attached of the better one.

 

3 levers seem to be frozen in some kind of a dance, all twisted together. 

 

Given the number and the size of the reeds, it seems pretty clear that this was a necessary design feature.

 

They all work really well!

 

Steve

DSCF4199.jpeg

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