When you read about a pipe organ or hear an organist talk, do you ever get the feeling that you have NO idea what all these “technical” terms are being thrown about? What is the difference between a stop and a rank? What IS a stop and a rank? What is a Barker Machine? What is a flue pipe?
There was a point in time where I couldn’t tell you either! Even to this day I’m still learning! So on this page I’m going to keep a running “dictionary” of my definitions for those who are interested to know what the blue blazes this guy (me) is talking about! For those of you who already know all this stuff… you don’t need this.
Barker machine –
Console – This is the part of a pipe organ from which the instrument is played. It contains the keys and the stop knobs and pedal board. Think of it as “flight control.”
Coupler – A coupler does exactly what it sounds like. It Couples! Ok, more specifically it couples one manual (keyboard) to another manual or to the pedal board. So you can play the stops of manual A, on manual B, if you use the coupler Manual A to Manual B Coupler. Makes sense?
Division – Not referring to mathematics here. Rather to how an organ’s stops or ranks are split up. Each manual and pedal has it’s own sets of pipes and that group of stops/ranks is called a division. So, for example: an organ can have a Great division, a Swell division and a pedal division. It so happens that’s what the organ at my church has!
Electric action – This is an organ that uses electronic signals and magnets to open the valve below a pipe when a key or pedal is pressed. The effect is instantaneous.
Flue pipe – A whistle! Ok, not quite a whistle – but same concept. Air enters the bottom of the pipe and is blown through the mouth of the pipe across the lip and it resonates up into the length of a pipe. Flue pipes include ALL flutes, diapasons (or principals) and gambas (strings).
Harmonic stop – A stop in which the pipes are built twice their normal length (causes them to speak and octave lower) and then overblown (HIGHER wind pressure) which causes them to speak an octave higher. Poor example, but… – Have you ever blown into one of those party “horns” really hard and suddenly it’s pitch changes and goes higher. It actually changes an “octave.” Same concept behind a Harmonic stop, you put more air in it and it speaks an octave higher. Well than if you build them twice their normal length that makes the tone lower (back to the original octave). The resulting sound is a full sound (musicians would call it lots of fundamental sound). Harmonic stops are generally used to strengthen upper octaves in stops – where the sound of pipes often can grow weaker the higher the pitch gets. Harmonic stops are most commonly seen as flutes and reeds (particularly trompettes) where the upper octaves can get a bit week. Incidently the Flûte Harmonique 8′ is usually my most favorite stop of an organ.
Pipe – This is one of the most important parts of a pipe organ! Imagine that! A pipe is what makes the sound of an organ. There is generally one pipe for every note on a keyboard for every stop. They can range in size to 32 feet tall down to a size about the same as your little finger. The smaller the pipe the higher the pitch. Pipes can be made of wood or metal.
Pitch (number on a stop) – The number on a stop indicates the pitch of a pipe. If you’re looking at a standard 61 note keyboard middle “C” can be found at middle “C” on the keyboard with an 8′ stop drawn. With that 8′ stop drawn the lowest pipe that can play on that stop is going to be 8 feet. Now a 4′ stop will sound an octave higher. If you play “middle C” on a 4′ stop you will get a pitch exactly one octave higher. So on a 16′ stop you get a pitch one octave lower… Remember the larger the number the lower the pitch. Some can go as high as 1′ (four octaves higher) and some, though it’s VERY rare, 64′ (three times lower). Also see Mutations
Rank – a set of organ pipes of the same kind and tonal color. There is one pipe for each pitch. So example, a Principal 8′ on a standard 61 keyboard will have 61 pipes that make up the rank. Some stops can have multiple ranks. (see for example, Mixture)
Scale (in reference to a pipes width) –
Stop – a graduated set of pipes of the same kind and giving tones of the same quality. (see also Rank). A stop and also refer to the tab or draw knob on the console that activates a rank of pipes (it can also activate multiple ranks if it’s a mixture). You can activate multiple stops at once! Sometimes Stop and rank are interchangeable in organ talk… Usually the name of the stop is engraved or written on the tab/Knob and is accompanied by a number. This number indicates pitch.
Swell – This is a division of the organ that is contained in a box with shutters. The shutters are then controlled by the organist from the console. The organist can open the shutters to control the loud/softness of the ranks contained in that division.
Tracker action (mechanical action) – This is an organ that is played where there is a DIRECT connection between the key and the valve below the pipe using rods and wire trackers. Mechanical organs give the performer complete control how the instrument is played. How fast you press the key (or pedal) on a tracker organ is how fast air is let into the pipe.