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Swell Shutters


Frank Fowler
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The control of swell shutters being touched upon in another thread gives enough scope to start a subject debate in its own right.

 

To start with,

 

1. What is the ideal shutter design.

 

2. Is it better to have the whole shutter front moving in unison.

 

3. Does independent (i.e. one at a time) shutter control give a

better crescendo.

 

4. On a large shutter front how does one control inertia particularly

with mechanical linkage to the Swell Pedal.

 

5. What are the problems with one swell box and two independently

controlled sets of shutters.

 

6. Etc.

 

FF

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I've been helping on a Sweetland job where the top shutters open slightly before the bottom ones, and consequently slightly wider. That seemed very effective indeed in the early stages of opening the box.

 

Slightly unrelated but I can't understand why the Infinite Speed & Gradation system didn't catch on. The one at St Mary's Southampton is incredibly controllable once you've got used to what the pedal's actually doing.

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Slightly unrelated but I can't understand why the Infinite Speed & Gradation system didn't catch on.  The one at St Mary's Southampton is incredibly controllable once you've got used to what the pedal's actually doing.

 

I've never tried an ISG system, but as an engineer it certainly appeals to me. However, from what I've been told, the main problem is that one can't judge the position of the shutters from the pedals.

 

I gather that many years ago when Flor Peeters gave a recital at Liverpool Cathedral, he was so bemused by the swell pedals that he refused to use them at all - in a programme including Franck!

 

JJK

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I've never tried an ISG system, but as an engineer it certainly appeals to me. However, from what I've been told, the main problem is that one can't judge the position of the shutters from the pedals.

 

 

Ah, but you can - there's a Morris Minor fuel gauge for each box under the relevant bank of stops which shows you how open they are!

 

The best bit is a clever switch that enables you to reverse the order of the pedals, or have both boxes operating simultaneously from one. It's ingenious.

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Ah, but you can - there's a Morris Minor fuel gauge for each box under the relevant bank of stops which shows you how open they are!

 

The best bit is a clever switch that enables you to reverse the order of the pedals, or have both boxes operating simultaneously from one.  It's ingenious.

 

You can now the gauges work again... They literally are Morris Minor gauges, too - Smiths fuel gauges with a slightly different face plate, I believe.

 

But yes, you don't intuitively know where the shutters are, but, of course, once you get used to an instrument, you can a) tell by the tone :( just "know".

 

Perhaps David Wyld can explain how they work? I've never really understood the engineering side of it.

 

Very long slow controlled crescendi are easy with it. A big bang is easy with it, but probably not as easy as with a balanced pedal. Open a bit - play - open a bit more - play, etc, is much easier with it than the balanced variety - just give it a quick kick when you get chance, and it'll open a bit at a time.

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I gather that many years ago when Flor Peeters gave a recital at Liverpool Cathedral, he was so bemused by the swell pedals that he refused to use them at all - in a programme including Franck!

 

 

Apart from Liverpool and my place, what other large organs have still got ISG's? Westminster?

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Apart from Liverpool and my place, what other large organs have still got ISG's? Westminster?

 

Sadly I think that might be it.

 

Westminster lost them at some stage (Harrison rebuild?). I did wonder about St George's Hall - however NPOR lists them as balanced (but I note that they are switchable to different pedals, as ISG's are). I'm a bit surprised if they were converted away from ISG, given that the Cathedral organist has been the curator in recent years. Anyone know the facts?

 

JJK

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If you open one shutter before the others, or one set of shutters before the others (should we have several sets of shutters on the same swellbox), the result will be

a nightmare, completely anti-musical.

 

Imagine this: you open one shutter only, the pipes that are immediately behind

will dominate the others!

 

A better idea is to have a non-linear shutter control, so that if we open the expression pedal 50% (thus at the console), the actual shutter opening would be say 10%.

 

In order to reduce inertiae: 1)-The shutter are made vertically, not horizontally as done with the first venetian shutters in the 19th century 2) the axes of the shutters

are at the centre of them 3) We can use modern materials (Aluminium for example) to reduce weight.

This indeed has already be done, but mind the "annihilating swell".

 

Pierre

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1. What is the ideal shutter design. 

 

          2. Is it better to have the whole shutter front moving in unison.

 

          3. Does independent (i.e. one at a time) shutter control give a

              better crescendo.

 

          4. On a large shutter front how does one control inertia particularly

              with mechanical linkage to the Swell Pedal.

 

          5. What are the problems with one swell box and two independently

              controlled sets of shutters.

 

Do you mean the shutter front itself or the control system?

 

On the shutter front, I don’t think you can beat solid timber shutters, though I’ve come across all sorts (apart from the metal versions apparently found in organs like Atlantic City). It depends on how important you think the transmission of sound through the closed front is - I think that solid shutters give the best closure.

 

Most of the new organs I’m familiar with (largely the work of one particular builder) have swell boxes made with a timber frame, ply on the outside, with anything from painted hardboard through to white-melamine beauty board on the inside face, and polystyrene aero-board in between. The shutters on these organs are usually made of 6mm ply on a solid frame with aero-board inside – certainly making for very light shutters. The idea was to create a highly reflective interior and whilst this might help the box open sound, I’m convinced that the reflection prohibits a good pianissimo effect, whereas a traditional box will absorb some sound when closed giving better results. J. W. W. did a line in hardboard boxes in the 60s – what opinions do readers have of these?

 

If one has to have electric action, the best option is a good whiffle-tree engine (of say 16 stages) but there are a number of caveats there too of course. They are expensive, tend to be noisy, take up a load of space and need high wind-pressures to work well. On the plus side one has the pneumatic force of 16 motors moving pretty much at once which means that a slam in either direction is achievable in theory at least. The concertina engine system is limited by the fact that pneumatic force is applied to the area of basically one motor, even if all stages engaged, and tend to be far more sluggish as a result. If one has the resources to ensure high wind pressure, and as many stages as possible, then a whiffle-tree could do the trick…I played an organ for several years with a second-hand 16-stage engine running on blower-pressure (about 4.5 inches) – it was pathetic; you could the move the pedal and wait a couple of beats before you heard any difference…

 

Independent shutters make the time element less of a concern, but usually at the expense of subtlety – try a cinema organ to find out! The Wurlitzer system certainly moves quickly, but is a lumpy, ‘wooshy’ sort of crescendo, fine if you want to slam the box open and shut, less good if you want to move gradually.

 

As for inertia – I suppose reducing the mass of the shutters will help (hence the endless variety of tricks used, including drilled, hollow etc. shutters). One can also improve mechanical control by gearing the trace mechanism so that the initial movement is very gradual, then speeding up as the shutters reach the fully open stage and ideally slowing down just before the end of the run to counteract the run-away effect of momentum – just needs a good engineering brain to do this! It is possible to get this ‘cam’ type action the wrong way round of course…

 

I have no experience of two independent fronts on one box, but I’m sure other commentators will have plenty to say on this – I think our hosts did this on their organ in St. Albans…maybe we’ll hear what the result was like!

 

The Willis ISG system is very clever – probably one of the most imaginative pieces of electric action engineering from the Willis atelier. Risking offending Mr Wyld again, it is theoretically not infinite at all – offering (as far as I can remember) five or six speeds in each direction, from a glacial one-minute full travel, to an incredibly fast slam in either direction. The infinite bit is down to the player deciding how much movement and how fast and moving their foot as required. As the open and closed directions are operated pneumatically, power is not an issue (assuming high wind pressure) and no springs or weights are required to hold the box open or shut. Doubtless a system that would become second nature with a bit of experience, I believe two issues have stood in its way – one being the very fact that it is so different traditional pedals which means it is very scary for first time players who don’t have the time to get used to it – we all know how off-putting a bad experience can be! The second reason is that because it was a Willis “exclusive” it was never going to be widely adopted – has Willis encouraged other builders to incorporate it when it first appeared it might have achieved more acceptance. The indicator bit always puzzled me - ok you might need to glance at these if you haven't been playing on the encolsed division, but if you are surely your ears might tell you how open or closed the box is?

 

Now that we are in the micro-processor era, the Willis ISG could be updated to make a very clever swell engine. The technology already exists as it is used in the direct electric swell motors made by Laukhuff, Taylor, Peterson et al – basically using a computer to identify the positions of both the swell pedal and the shutters and then to instantly operate the motor to make up any difference. The problem with the electric motor is, once again, speed – just look at the stats. Adapt the Willis engine, which is of course pneumatic (power you can store!), to this form of control and bingo – fast and precise! All you need is someone to work out the programming so that the processor can establish how fast the pedal is being moved, and engage an appropriate speed stage in the engine - I should patent this idea…lol. That said I believe the Peterson electric system responds to the speed of pedal travel as well the position. Either way it might be easier to save the expense and move the console closer to the organ and do it with a mechanical trace…

 

All in all, I don’t think you can do better than mechanical control for a swell pedal – I wonder what is the longest run achieved mechanically? I believe that the swell trace in Liverpool Met goes down into the car park and back up again…

 

D

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If you open one shutter before the others, or one set of shutters before the others (should we have several sets of shutters on the same swellbox), the result will be

a nightmare, completely anti-musical.

 

Imagine this: you open one shutter only, the pipes that are immediately behind

will dominate the others!

 

Pierre

 

The example I gave had one shutter opening perhaps 2% before the next one down, which was 2% before the next one below, etc. The early stages of the crescendo are much easier to manage, and because when fully open some are more open than others, projection is greatly helped.

 

I'm sure nobody would wish to open one shutter completely before starting on the next. But I can't see any reason why two shutter fronts shouldn't be controlled seperately, to extremely good musical effect. I once played a "buried in the chancel" job which had two shutter fronts - it was like an extra manual, being able to accompany the choir on fairly full registrations, and being able to open the set facing the congregation for hymns.

 

Having used both mechanical and electropneumatic pedals operating both horizontal and vertical shutter fronts I think that decision needs to be made solely on the basis of projection into the building. AJT's for instance has one of each - the swell sound is sent down the building through vertical shutters angled down the nave, whereas the choir is horizontal (actually pointing upwards rather than down). There are occasions when a vertical front is quite inappropriate, for instance in a division placed high in a building. I personally find that horizontal shutters pointing downwards lead to a more natural feeling pedal. As for inertia, surely it's down to good engineering and having sufficient space for long arms with counterbalances? A heavy door is not really any more difficult to open than a small one if leverage is applied in the correct place at the correct angle. The Romsey one for instance is a big heavy front and a very long run but it's ideal in use - there's a whacking great weighted arm inside the case that assists it.

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David, this will work only with horizontal shutters, not with modern, vertical ones.

 

Pierre

 

I know. The example was a late 1800's Sweetland with a trigger swell control. It just struck me as a good idea and thought I would mention it.

 

Perhaps that's another question for Frank's list - vertical or horizontal. Personally, unless a buried location dictates otherwise, I would have horizontal every time - I think you get much better control through the pedal, much better dust protection for the reeds, the ability to do things with projection, and much better engineering control. The shutters naturally want to be closed, and the mechanism is there to discourage them. Of course there must be a counterbalance; otherwise it would not be a balanced pedal. Two equal and opposing forces must surely be not far off the definition of a lack of inertia?

 

This is just my personal preference - the few vertical fronts I have played with mechanical pedals I found either to have a completely dead feel or (with larger shutters) to gain too much momentum and go on doing their own thing, swinging and bouncing all over the place if you got them moving too fast.

 

Are vertical shutters really "modern"? I can think of lots of new organs with horizontal ones, from a wide variety of builders & styles, and very few with vertical.

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"Two equal and opposing forces must surely be not far off the definition of a lack of inertia?"

(Quote)

 

No, the inertia is simply defined by the weight (not the force, or torque) of all the moving parts (by the leverage).

So if we have an X system with say 10kg off-balance, and that we balance it using another 10kg as a counter-weight, we now have a balanced system but with more inertia. It will work well slowly, but should you want it to go fast, it will even more "do its own thing".

 

Horizontal shutters go with hitch pedals, like Franck had. A balanced system without counter-weights imply the vertical species.

As for dust in the reeds, the true bad idea in this respect are shutters placed on the roof of the box!

 

Pierre

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No, the inertia is simply defined by the weight (not the force, or torque) of all the moving parts (by the leverage).

So if we have an X system with say 10kg off-balance, and that we balance it using another 10kg as a counter-weight, we now have a balanced system but with more inertia. It will work well slowly, but should you want it to go fast, it will even more "do its own thing".

 

Horizontal shutters go with hitch pedals, like Franck had. A balanced system without counter-weights imply the vertical species.

As for dust in the reeds, the true bad idea in this respect are shutters placed on the roof of the box!

 

Pierre

 

Horizontal, therefore hitch pedal? That's a very sweeping statement, and rather over the top I think.

 

As I am far more likely to require accurate control of the swell pedal at very low speed than very high, I am very happy to keep some inertia and accept that the box will only open as fast as it wants.

 

I suppose it's like the clutch and brakes of a car - foot and leg muscles are only capable of so much refinement (without requiring an abnormal level of concentration, anyway), and opposing an interacting force gives you greater control than merely reaching then breaking a point of friction.

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Horizontal, therefore hitch pedal?  That's a very sweeping statement, and rather over the top I think.

In many German organs from the early-romantic era, you find exactly that: Horizontal shutters controlled by a hitch pedal. Sometimes these shutters are sprung, sometimes they are weighted so that they return to the closed position. Boxes like these usually housed not the enclosed-Great type of Swell division but only the most delicate voices, reeds as well as flues, of the entire organ. Accordingly, the shutter would never open fully but only a few centimeters.

 

It would be news to me, however, if the Sainte-Clotilde had had horizontal shutters -- didn't Cavaillé-Coll build vertical ones exclusively, taht were sprung in his earlier organs?

 

Of todays shutter systems, there are as well the doors folding symmetrically, which are used sometimes for Brustwerk shutters; and there is the Mühleisen system, in which horizontal shutters turn as well as fold, so that two neighbouring shutters form a V-shaped unit when the box is open. By this method, the front of the box can be opened wider than possible with individual shutters, and projection problems with uniformly opening shutters are prevented.

 

Best,

Friedrich

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If you open one shutter before the others, or one set of shutters before the others (should we have several sets of shutters on the same swellbox), the result will be

a nightmare, completely anti-musical.

 

Imagine this: you open one shutter only, the pipes that are immediately behind

will dominate the others!

 

A better idea is to have a non-linear shutter control, so that if we open the expression pedal 50% (thus at the console), the actual shutter opening would be say 10%.

 

In order to reduce inertiae: 1)-The shutter are made vertically, not horizontally as done with the first venetian shutters in the 19th century 2) the axes of the shutters

are at the centre of them 3) We can use modern materials (Aluminium for example) to reduce weight.

This indeed has already be done, but mind the "annihilating swell".

 

Pierre

 

Some good points, Pierre.

 

I always prefer vertical shutters. I also wonder about boxes with two sets of shutters, or shutters in the roof (e.g., the Solo box at St. Paul's, London) - does this reduce the effective diminuendi possible? After all, there are more edges for the sound to leak out.

 

The only exception I would wish to make is Gloucester. Here, due to the positioning of the Swell box, it is actually advantageous to have east and west shutters operating from separate pedals. Then, depending on whether one is accompanying a service in the Nave or the Quire, one can have on set closed (as a reflector) and the other set for expression.

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About horizontal shutters by ACC I have no data; but the big, "symphonic" Swell with reed chorus 16' included is a late thing. It's highly probable ACC followed

FHW in that respect!

So the majority of Cavaillé-Colls "Récits" where the little Echo-in-a-box kind

as Sprondel describes.

But as there are nearly no soft stops in french organs, even the romantic ones, so they rely more heavily by far on the Swellbox than the german organ, which can

dispose of any Swellbox at all -and indeed often does, like in Wemmetsweiler in 1903-. The normal Crescendo on a Sauer or Walcker is done with the boxes (usually one for an echo division) fully open.

 

Pierre

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About horizontal shutters by ACC I have no data; but the big, "symphonic" Swell with reed chorus 16' included is a late thing. It's highly probable ACC followed

FHW in that respect!

 

Pierre

 

 

====================

 

If one ignores the famous 1839 Bucholz organ at Brasov (formerly Kronstadt), Romania, this is largely true, but this particular organ has two enclosed departments with full reed choruses; all safely pre-dating both FHW and CC.

 

Of course, it doesn't "quite" have the same effect as "the big symphonic Swell," but it's getting close.

 

If anyone is interested, I'll dig among the files and post the specification.

 

MM

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====================

 

If one ignores the famous 1839 Bucholz organ at Brasov (formerly Kronstadt), Romania

 

 

====================

 

 

I cannot remember the name of the church at Brasov, Romania, but here is the specification (not actually double-checked and proof-read, but doubtless very close):-

 

 

MANUAL? (Keyboard no.3 - Oberwerk position)

 

Principal 16 fuss

Quintato"n 16 fuss

Principal 8 fuss

Gemshorn 8 fuss

Viola da gamba 8 fuss

Rohrflo"te 8 fuss

Nasard 5 1/3 fuss

Octava 4 fuss

Spitzflo"te 4 fuss

Waldflo"te 4 fuss

Quinta 2 2/3 fuss

Superoctav 2 fuss

Scharff 5 fach

Cimbel 3 fach

Cornett 5 fach

 

OBERMANUAL (In normal Hauptwerk position!!)

4th keyboard

 

Bourdon 16 fuss

Principal 8 fuss

Salicional 8 fuss

Hohlflo"te 8 fuss

Gedact 8 fuss

Octava 4 fuss

Fugara 4 fuss

Rohrfl"ote 4 fuss

Nasard 2 2/3 fuss

Superoctav 2 fuss

Mixtur 5 fach

Hautbois 8 fuss

 

 

UNTERMANUAL

bottom keyboard - behind Obermanual

enclosed in SWELL BOX

 

Salicional 16 fuss

Principal 8 fuss

Viola da gamba 8 fuss

Flauto traverso 8 fuss

Gedact 8 fuss

Octava 4 fuss

Viole d'amour 4 fuss

Flauto dolce 4 fuss

Gemshorn 2 2/3 fuss

Decima quinta 2 fuss

Progressio harmonica 3 bis 5 fach

 

ROHRMANUAL

2nd keyboar

Soundboard behind Manua

enclosed in SWELL BOX

 

 

Violine 8 fuss

Rohrflo"te 8 fuss

Principal 4 fuss

Fagott 16 fuss

Clarinette 8 fuss

Vox angelica 8 fuss

 

PEDAL

 

Principal 32 fuss

Principal 16 fuss

Subbass 16 fuss

Principal 8 fuss

Gemshorn 8 fuss

Quinta 5 1/3 fuss

Octava 4 fuss

Mixtur 4 fach

Trompete 8 fuss

Cornetta 4 fuss

 

 

Untersatz 32 fuss

Violone 16 fuss

Nasard 10 2/3 fuss

Violone 8 fuss

Bassflo"te 8 fuss

Contra posaune 32 fuss

Posaune 16 fuss

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====================

I cannot remember the name of the church at Brasov, Romania, but here is the specification (not actually double-checked and proof-read, but doubtless very close):-

...

ROHRMANUAL

2nd keyboard

Soundboard behind Manual

enclosed in SWELL BOX

Violine                     8  fuss      

Rohrflöte                8  fuss      

Principal                  4  fuss      

Fagott                     16 fuss        

Clarinette                8  fuss   

Vox angelica             8  fuss     

Let me add the Trompete 8' here. This stop is, however, the only beating reed in the entire division, which is, according to an article in "Orgel International" (1998/2, p. 19–21), rather lyrical in character, even though it is on 100 mm of wind (about 3 3/4 inches). All the other reeds, the Fagott included, are free.

 

The organ must be quite something -- actually the only German-romantic organ of that builder, era (1839) and scope that survives today. I really wish I could visit there and listen to the organ some day. Until now, eastern Romania was a bit far off my routes.

 

Best,

Friedrich

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Thanks MM, this organ is very interesting indeed.

It seems quite close to Schlimbach's ideas as expressed

in his 1811 treatise, in which Dom Bédos and Joachim Wagner

are the main references.

This said, I am still searching that second reed chorus?

 

 

Pierre

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So far, so good ("So weit, so gut"),

 

I'm still searching the second reed chorus, but actually

it might obtain...None.

The Fagott we should not compare to the Bassoon; during

Bach's time it was indeed a Regal.

Regals were replaced as "quiet" reeds by free reeds, and so

we have it here. Free reeds were extremely in vogue in Germany

since the begin of the 19th century, and contrarily to what happened

in France and England, they remained fashionable up to the end

of that century (an intermediary state of affairs being find in Belgium,

as usual). Mr Mander once reported here Schulze used free reeds even for

Pedal stops at Doncaster.

In german organs "proper" (I mean what we understand with that today) "chorus"

reeds you will find only at the Pedal. By Walcker for example the first true manual reed choruses date back 1909 (Reinoldikirche Dortmund), and were made because the specification was drawn by Emil Rupp. Rupp even brought Oscar Walcker with him to pay a visit to Mutin in Paris in order he could understand what kind of reeds he wanted.

 

So these Fagotts were intended for light registrations, not big choruses, or to be used

with the Diapason chorus just to color them somewhat.

 

The idea to use this kind of stops, like this:

 

Fagott 16'

Hautbois 8' (french)

Clairon 4' (french)

 

(Cited by Hans-Gerd Klais in "Überlegungen zur Orgeldisposition")

 

.....Is a typically 20th century one, used for the first time in the "Kompromissorgeln" (ecclectic organs) from about 1930 up to 1970 -and coming strongly back today by the way-. The aim is to try to combine two meals in one: have two solo stops that will be used as a chorus with the Clairon.

But no one baroque builder would have tried that...

 

Pierre

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