This article explains many of the buttons and switches that appear on a typical organ console. Most organs share at least some of these controls, so there is a certain amount of “standardization” among, at least, American and Canadian consoles. These standards include the height of the keyboards, the number of keys on a keyboard (61), and the number of pedal keys (32). As far as the number of other controls, pretty much anything goes!
Under each keyboard (also called a manual) is a row of round white buttons called pistons. When pressed, they change the settings of the stops which the organist is using. Each piston can be preset to a desired combination of stops. Each keyboard, including the pedalboard, has its own set of pistons that control only the stops on that keyboard. There is also a set of pistons, called Generals, which control the whole organ. When all else fails, beneath the lowest keyboard, to the far right, is that cure-all for a bad Sunday morning, the General Cancel, which shuts all the stops off.
There are a total of 93 pistons on the new organ, most of which will be programmable for 64 different combinations. This is particularly handy when several people are using the organ: they can each have combinations of their own without upsetting those of the “resident organist.” An LED display shows the setting in use at the time. Another special piston is the “Sfzorzando," or Full Organ piston, self-explanatory. The opposite of the General Cancel, this brings on everything!
Above the uppermost keyboard is a row of rectangular rocker tablets. These are called couplers. They allow the organist to move, for instance, any of the stops on the Swell division to the Great, Choir or Solo division. This enables the organist to combine stops in ways impossible without couplers. Also, all the manual stops can be coupled to the pedals, but not vice versa. Full organ occurs when all the manuals are coupled together with all stops playing. There are a total of 35 coupler tablets, because stops not only can be coupled at their basic pitch, but also an octave higher or an octave lower. Got that?
Immediately above the pedal keyboard are four what look like large accelerator pedals. Three of these control the shutters in those divisions that are under expression. The one on the far right is called a crescendo pedal. It adds a predetermined sequence of stops as it is opened. This pedal will have the ability to be programmed for four different sequences, so it is possible to build the sound by quickly adding stops “by foot” and in the style of the music being played.
Also above the pedal keyboard are some 33 “toe studs,” some of which duplicate the pistons under the keyboards (vital when the organist only has a foot available with which to change stops, which frequently happens when conducting and playing at the same time), and some of which control certain couplers and special stops.