In Lesson 1: Understanding the Parts of the Organ, I presented an overview of the console. Today, with more information provided by Carol Dean, we'll delve into a little more depth on stops, couplers, pistons, and combination action.
Stops and Couplers
On most larger pipe organs, the pipes which are accessed by each individual keyboard are grouped in specific areas of the case. In smaller organs, with two manuals, the great is open and the swell is grouped together in the swell box. The Salt Lake Tabernacle keyboards from bottom to top are: Choir/Positive, Great, Swell, Solo/Bombarde, and Antiphonal, and each has its own area in the case for the related pipes.
In the newer electronic organs, pipe organ sound is actually sampled and saved into a computer chip which is accessed electronically from the different keyboards or divisions.
As mentioned in Lesson 1, couplers belong to the non-speaking stop category--they affect the speaking stops but have no sound of their own. The couplers you will most likely see on your two-manual church organs are: Swell to Great, Great to Pedal, Swell to Pedal, and possibly one or more Sub or Super couplers such as Swell to Swell 16' or Swell to Swell 4'.
Octave (sub or super) couplers work within a manual to double the stops up or down one octave. For example, if you have one 8' Swell stop selected, engaging Swell to Swell 4' (super coupler) and then playing middle C will result in your hearing middle C and the C above middle C. If you instead select Swell to Swell 16' (sub coupler), you will hear middle C and the C below middle C. Most organs with sub and super couplers will also have a Unison Off stop tab or reversible thumb piston (explained below). If the Unison Off is engaged along with an 8' stop (for example) on the Swell and the Swell to Swell 4', you will not hear the stop at the pitch indicated on the tab (8'). You will only heard the effect of the super coupler–the pitch one octave higher than the note you are actually playing.
In a pipe organ, a rank is a row of pipes in one tone color, with one pipe dedicated to each key. Each stop turns a rank of pipes "on" or "off." In electronic organs, each speaking stop accesses sample pipe organ sounds that have been digitally stored in computer chips–technology called PDI or parallel digital interface.
Pistons and Combination Action
Thumb pistons and toe studs are part of the combination action system. Depending on your organ, some pistons are available both as thumb pistons and toe studs.
A Tutti or Sforzando piston functions like a crescendo pedal that is all the way forward, selecting every stop available on the organ except those that do not work well in a large ensemble sound, such as solo reeds, celestes and the tierce.
Although they appear identical to thumb pistons and toe studs, reversibles serve an entirely mechanical function independent from the combination action. The oft-used Great to Pedal reversible can serve as an illustration. When it is pressed the first time, the Great to Pedal coupler is drawn, or engaged (in most cases the drawknob or stop tab actually moves into "on" position). When depressed the second time, the action is "reversed," retiring the coupler back into "off" position. Depressing a Great to Pedal reversible repeatedly simply brings the drawknob or stop tab in and out or up and down. The most common reversible pistons on the smaller electronic organs are: Tutti (or Sforzando), Great to Pedal, Bass coupler, and Melody coupler.
Organs have general pistons and most organs also have divisional pistons. These pistons are usually programmable, although some organs have one or more memory levels which are locked.
General thumb pistons are numbered and are usually located to the left of other thumb pistons, under both the swell and great manuals. Divisional pistons are also numbered, affect only one division of the organ, and are generally located just under the manual of that division.
Above the pedalboard on the right there are a group of divisional toe studs that only memorize stops for the pedal division. The group on the left are the general pistons which affect all stops and couplers on the organ. These are repeats of the thumb generals below the manuals. The last kind of toe studs you will see are called reversibles. These are usually spread out across the bottom of the console, above the generals and pedal divisionals.
In newer organs, combinations are stored in a computer memory. To set a combination, pull the desired stops, choose your memory level, hold the setter button (usually labeled "Set"), and press the desired piston. Larger organs and newer organs generally feature a system of memory levels: each organist is assigned a level or a range of levels and is able to keep his registrations separate from those of other organists who play the instrument. It is a good idea to keep a sign-up list on your organ so that each organist's settings aren't inadvertently cleared by another ward, stake, or guest organist.
If more than one organist uses your organ, create a sign-up list so that each organist can sign up for at least one memory of their own.
Looking back over the hymns you have learned, and the prelude that you have played, program your memory level in your organ for the registration changes you have chosen. Practice playing through these hymns, using the thumb pistons or toe studs.
Plan 10 to 15 minutes of prelude music, using the programmable pistons to create a variety of colors. Make a note of which piston to use when on your music. Practice until you can smoothly change between pieces. Play prelude for Sacrament meeting or another church meeting, using these thumb pistons.
I hope this lesson was helpful to you. Utilizing the programmable feature on your organ allows for a smoother prelude, without sacrificing a variety of tone colors or allowing for large moments of silence while new stops are selected.
Continue on to Lesson 18: Seeking More Instruction.