(con't from Part I)
Originally developed in 1933, the American Guild of Organists (AGO), recognizing the need for a system of standards, outlined some recommended console measurements and other information for pipe organ builders concerning the construction of consoles, pedalboards, pedal accessories, manuals, couplers, order of stops, and combinations for a variety of organs to meet the needs of the greatest number of players.
These recommendations became known as "AGO Specifications," and any console built along these lines is described as an "AGO console."
One of these specifications has to do with the all important matter of bench height [See blog, What About Bench Position]; it explains that the normal height of the top of the bench above pedal middle E2 should be 20-1/2 in., adjustable up or down from this height by as much as 2 in. in either direction by means of a crank.
The remaining specifications may be summarized as follows:
Compass of the manuals: 5 octaves of 61 notes from C2 to C7 on the piano keyboard.
Compass of the pedalboard: 2-1/2 octaves of 32 notes from C1 to G3 of the piano keyboard.
Manual overhang of the keys: 4-1/4 inches depth to 2-1/2 inches height, surface to surface; manuals may slope toward Great or be level.
Manual depth of touch: 5/16 in. to 3/8 in. scant.
Manual point of speech: midway between top and bottom of travel of the keys.
Manual weight of touch: 3-1/4 to 3-3/4 oz., with tracker touch recommended on electro-pneumatic instruments.
Radiation of pedalboard: 8 ft. 6 in. radius; maximum permissible 9 ft. 6 in., minimum 8 ft. 6 in.
Concavity of pedalboard: 8 ft. 6 in. radius; maximum 8 ft. 6 in., minimum 7 ft. 6 in.
Length between heelboard and toeboard: 27 in.
Length of playing surface of pedal sharps: 6-1/2 in.
Height of pedal sharps above naturals: 1 in. at player's end, 1/2 in. higher at the other.
Width of playing surface of natural pedal keys: 7/8 in. -- 15/16 in.
Radius of curve of pedal sharps: Fronts, 8 ft. 6 in., back 9 ft.
Distance, center to center of adjacent natural pedal keys at front end of sharps: 2-1/2 in. This makes the pedal octave 17-1/2 in. Most important of all the measurements, it is important that this distance be maintained.
Depth of pedal touch: 1/2 in. at front line of pedal sharps.
Weight of pedal touch: 2-1/2 -- 3 pounds at front line of pedal sharps.
Point of pedal speech: midway between top and bottom of travel of the pedal keys.
Pedal Couplers: Manual to Pedal couplers 8' and 4' from each manual to Pedal (except only 8' on Great). Reversible pistons operating either Pedal or Manual couplers should add 8' couplers but remove both 8' and 4' couplers. Great to Pedal Reversible duplicated by toe stud at right of crescendo shoe.
Pedal to Manual left to right location: centered under the manuals.
Pedal to Manual front to back: Pedal D#2's front end 8-1/2 in. to 10 in. back of plumb line dropped from edge of white keys of lowest manual of 2 manual or 3 manual console, 11 in. on a 4 manual.
Pedal to Manual vertical: 29-1/2 in. between playing surface of natural keys of lowest manual and middle natural key (E2) of pedal.
Knee panel and toeboard carrying the pedal accessories to follow the 9 ft. radius curve of the distant end of the pedal sharp keys.
Crescendo Shoe: heel end of playing surface of shoe to overhang pedal sharp keys by 1-1/4 in. maximum forward position, or be placed 3/4 in. maximum distance back of them. These dimensions are for shoes in closed position.
Swell Shoe: to be located directly in front of the pedal E2-F2 gap.
Choir or Positiv shoe to left of Swell, Solo shoe to right of Swell.
Crescendo shoe invariably to the right of all others, and slightly raised.
Great shoe in small 2 manual organs, where Great is enclosed, to replace Choir or Positiv shoe at left of Swell shoe.
Couplers: All manuals couple to Great and Pedal. Swell couples to Choir or Positiv. Choir or Positiv couples to Great.
The order of stops within each division is: 16' flues, 8' flues, 4' flues, 2' flues, Mixtures, 16' reeds, 8', reeds, 4' reeds. Stops not mentioned in the above take their normal position according to pitch in their respective flue and reed divisions. Loudest to softest is the order within pitch groups (left to right for stop tabs, bottom to top for drawknobs).
For stop tab consoles: 2 rows over top manual; top row, left to right: Swell, Great, Choir, Solo, Echo, with couplers in each division following the stops. Lower row: Pedal, Great, Positiv.
For Drawknob consoles: Left jamb: Pedal and Swell. Right jamb: Solo, Great, Choir, Positiv. Additional divisions (Echo, Antiphonal, String, etc.), when present, often occupy unused space on the left jamb. Order within the division as given, from bottom to top. Tremulants at top. Intramanual couplers above each division of stops.
Order of couplers above top manual on drawknob consoles: left to right. Pedal couplers: Great, Swell, Choir, Positiv, Solo. Manual couplers: Swell to Great, Choir or Positiv to Great, Solo to Great, Swell to Choir, Solo to Choir, Great to Choir.
The AGO also suggests that where there are 8 or more manual pistons for each manual, that they start under middle C4 of each manual and be spaced 1-1/8 in. apart. General pistons, divided under Swell and Great manuals, to the left of the manual pistons, with space enough between the 2 groups for Great to Pedal, Swell to Pedal, and Swell to Great reversibles. General pistons to be duplicated by toe studs on the left of the expression shoes. Pedal pistons by toe studs only on the right of expression shoes.
Consoles built in America prior to 1933, obviously, were not subject to these standards; certain common patterns of building were in use back then to be sure but builders worked then as they do now in their own well-worn trade grooves; therefore it should come as no surprise that many of these consoles deviated to some extent, technically, with AGO standards as we have them today.
We see this particularly with respect to the pedalboard which in America was often built 32-note straight concave; the manual point of speech in some instruments with electrically assisted action was also much nearer to the top of the key travel than midway between top and bottom.
The historic IV/53 Kimball symphonic organ constructed in 1924 for the Cathedral of the Scottish Rite in Saint Louis, Missouri is an example of this [See menu bar, Photos 3].
It will also be noted that some "AGO standard" consoles being built today do not slavishly follow each and every one of these recommendations to the letter but may exhibit very minor differences.
For example, the 1997 all digital "AGO standard" console in the above photo lacked 4' Manual to Pedal couplers, the Solo drawknobs were on the left jamb instead of the right jamb, and Manual to Pedal and intermanual coupler rocker tabs were not located above the top manual ... all couplers were operated by reversible thumb pistons instead [See blog, Step Up Instruments, Part V].
The pedalboard (photo) was also a little different; it was 32-note radiating concave but where the radius of the back curve of the pedal sharps should be 9 ft. to conform to the standard it was straight instead ... the knee panel and toeboard carrying the pedal accessories (toe studs) therefore could not follow a 9 ft. radius curve of the backs of the pedal sharps (which made the toe studs more difficult to find blindly with the toes, all of them being impossible to see when seated on a tall bench).
The pedal sharps were also shorter than the 6-1/2 in. standard; the length of the pedal sharps began at 4-3/4 in. on middle D#2 and increased outward from there both ways by 1/4 in. increments to the standard 6-1/2 in. at low D#1 and high D#3 ... the 2 extreme pedal sharps (C#1 and F#3) were ergonomically lengthened to 7-1/2 in. and did not follow a front radius curve of 8 ft. 6 in. (photo).
The top of the non-adjustable bench that came with this digital organ followed the standard and measured 20-1/2 in. above pedal middle E2, but for one player 6 ft. tall this was entirely too low; the solution was to replace the original bench with another non-adjustable spare bench that was 2 in. higher; for this player the higher bench was an incredible improvement in control, where he was able to reach everything easily and play the pedals blindly and effortlessly with much greater deftness and assurance.
NOTE: In America the average height of an adult man is 5'10" and for women 5'4" with a median height of 5'7" to which the 20-1/2 in. AGO standard bench height is suited; it should come as no surprise then, that an organist 6 ft. tall, who's 5 in. taller than the median, needs a bench higher than the standard; conversely, a bench lower than standard height would be needed by someone 5'2" tall, who's 5 in. shorter than the median.
The instrument doesn't fight the performer when the bench is high enough; on the contrary, organ playing becomes as easy and as natural as breathing [See blog, What About Bench Position].
The size of the rectangular wooden bench top is not specified in these standards, but the entire bench is often built narrower at the top than at the bottom; if the bench legs are flared into an "S" curve to span the pedalboard, then the bench top need not be any larger than 3 feet long by one foot wide by one inch thick; the edge of the bench where the player sits closest to the bottom manual seems to work best when it's well rounded.
It will be noted that a bench back rest, a Pedal to Great (Automatic Pedal) unison coupler, a Tutti (sforzando) piston, a Master Swell coupler, lighting for the rack and pedalboard, and the material, size, and shape of the rack are not specified in these standards either, nor is the amount of throw for drawknob consoles; these features are left to the builder's discretion.
NOTE: Drawknobs traditionally move in and out, and the traveling distance of the knobs is known as the "throw." For Anglo-American organs with electrically or pneumatically assisted stop action the throw is typically 1/2 in. -- 1-1/4 in. For French, Dutch, German, and similar instruments having mechanical action drawnobs without electrical or pneumatic assist the throw could be 1-6 in. or more.
A wide variety of MIDI pedalboard types are being manufactured these days which can be connected to electronic manuals and Hauptwerk software to create a virtual pipe organ [See blog, Virtual Pipe Organ (VPO)] which mimics various national and historical styles of organ building.
These types include 32-note (C1-G3) straight, 32-note straight concave, 32-note radiating concave (AGO), 30-note (C1-F3) straight, 30-note concave, 30-note radiating concave, 27-note (C1-D3) radiating flat, and even 25-note (C1-C3) radiating flat.
It will be noted, however, that the term "AGO pedalboard" may only be ascribed to one of these types (32-note radiating concave) and, even then, as outlined above, it may show certain deviations, technically, with exact AGO specifications.