From carols to chorales, cantatas and hymns - If there is one musical instrument that dominates the Christmas holidays, it would undoubtedly be the one known as the "king of instruments", the Organ. In this video and article, Chuck Nelsen from Cunningham's Classic Organ Group gives an in-depth tutorial to pianist Hugh Sung on how the organ works and how this incredible collection of pipes, of keys, stops, buttons and pedals that gives a single player the power to sound like an entire orchestra!
From Wikipedia: “The origins of the pipe organ can be traced back to Ancient Greece and the Hydraulis in the 3rd century BC. The wind supply was created by the weight of displaced water in an airtight container. By the 6th or 7th century bellows were used to supply Byzantine organs with wind. The first organ of which any detailed record exists was built in Winchester Cathedral in the 10th century. By the 17th century, most of the sounds available on the modern classical organ had been developed. From that time, the pipe organ was the most complex man-made device — a distinction it retained until it was displaced by the telephone exchange in the late 19th century.” So , so what is this modern Amazing Music Machine called The Organ? This article will begin to scratch the surface in showing you this Magnificent Music Machine! Let’s first contrast the acoustic piano, and how it produces sound, with the classic ‘organ’. An Acoustic Piano produces tone from hammers striking strings, and the pianist creates enormous range of nuance with their ‘touch’ and expression --- very soft to very loud. An organ, let’s talk a windblown pipe organ for now, produces sound by air flowing through pipes which ‘speak’ at a particular ‘frequency or pitch’ and ‘timbre or type of sound’ based on the pipe’s size and its “design, material, and construction”. There are metal pipes, wooden pipes, all shapes and sizes -- and ranging in size from that of a small pencil up to 32 feet in length (or in an extreme case even 64’)! The longer the pipe, the lower the pitch of note played, the shorter the pipe the higher the note or pitch. In an organ there are hundreds or even many thousands of pipes played via the keyboards (and pedals)!
Let’s look first at how pipes are
organized
, then we will see to the FAMILIES of pipe
sounds
!
Organization – Ranks and Stops and Pitches:
A Rank of pipes can be defined as a set of the 61 pipes/notes played on the organ keyboards, or the 32 notes on the pedalboard. Each rank has a particular sound-type and plays at a particular pitch range. Ranks are turned ON & OFF by so-called “STOPS”. The STOPS identify/name and ‘select’ for playing a rank of pipes. The ‘name’ on the Stop designates the voice and the actual length of the lowest note of the rank. For Example, a Diapason 8’ stop is a rank wherein the lowest note is a pipe actually 8 feet long! As you go UP the keyboard, the pitch of course gets higher as the pipe lengths get shorter. Note: A STOP at 8’ will sound
the middle “C” on the organ keyboard at the same pitch as MIDDLE “C”
on the Piano! This is called a UNISON Rank.
A 16’ rank plays at one octave lower than an 8’ rank. A 32’ rank an octave lower than that (yeah, and the lowest note length really is 32 feet). A 4’ rank plays at an octave higher than an 8’, an a 2’ at an octave still higher. A “mutation” rank/stop plays at a ‘harmonic series pitch’ above an 8’ rank’s pitches: For example: A Middle “C” on the keyboard of a 2 2/3’ stop actually plays at one octave plus one fifth (1/5) above that unison pitch… The lowest note of the rank is actually 2 2/3’ long). Another example: A 1 3/5’ mutation stop plays two octaves and 1/3 above the unison. With the ‘octave’ and ‘mutation’ stops, the organ can play ‘harmonically’ quite effectively! Some STOPS control more than one Rank of pipes at one “GO”. These stops are designated with Roman numerals indicating the number of ranks being played at once: For example, a Flute Celeste II plays two ranks, and a Mixture IV plays four ranks at once…
FAMILIES OF SOUNDS:
There are four basic FAMILIES of pipe sounds, each creating their own particular ‘kind of sound’… This is where you get the different ‘colors’ of sounds in an organ: Soft, loud, mellow, strident, raspy, flute-like, orchestral, strictly ‘organ’ sounding: Diapasons/Principals (foundational, typical ‘organ’ sound, non-orchestral) Flutes (orchestral and non-orchestral, many different timbres/colors) Strings (orchestral in flavor but distinctly organ-like) Reeds (orchestral and non-orchestral: Trumpet, Trombe, Clarinet, Oboe, Tuba, Vox Humana) (subtle to hair-raising) The first three are also called ‘flue’ pipes: Air flows inside and over the ‘mouth’ of the pipe, and the tone is produced by the air’s action around the mouth, and the flow of air up and down in the body of the pipe (the resonator). This is similar to when a flutist’s embrasure blows over the mouth of a flute, or perhaps more accurately, a recordist’s blowing into their recorder. The Reeds, by comparison, have a metal or other ‘reed’ in the base of the pipe which vibrates as air passes over it. The sound of the vibration is then amplified by the ‘resonator’ portion, the rest of, the pipe. So… How are all these different ranks of voice types, and their stops, deployed across the organ’s keyboards and pedals.
DIVISIONS:
Each Keyboard and the Pedalboard correspond to a DIVISION of the organ. A Division contains a selection of Stops at different pitches, and generally from
each
of the Families of sound: Diapasons, Flutes, Strings, and Reeds. On this example organ we have three keyboards and a pedalboard, four divisions – The middle keyboard is the GREAT Division, The top is called the SWELL Division, and the bottom keyboard is the CHOIR Division. The Pedal Division is played by the feet! The STOPS controlling a Division’s sound pallet are all grouped together: On this instrument the SWELL STOPS and PEDAL STOPS are by convention on the left…The GREAT STOPS on the near right, the CHOIR STOPS far right. Two Questions to ponder: Firstly, which particular STOPS/VOICES appear in each Division? This is ‘the art of the organ builder’ and an excellent subject for another article! Secondly, what ‘combination’ of voices/stops does one select to play at any given time? This is “the art of REGISTRATION… Also a subject for another article! For this article, let’s finish with two other ‘organizational’ aspects of the Amazing Music Machine, Enclosed divisions, and Combination Selection.
ENCLOSED DIVISIONS/EXPRESSION PEDALS:
The pipe voices/stops themselves have their own relative volume levels depending on the ranks’ physical characteristics. The notion of controlling the volume of the organ sounds is in part how many of the stops are played, and in what combinations. Unlike the piano where the artist can physically play louder or softer by touch, the organist cannot do this. A pipe speaks as a function of the pipe-type and the wind pressure applied to it. In order to be able to control the volume dynamics of an organ, pipes can be enclosed. Some whole Divisions of the organ are literally ENCLOSED IN A BOX! In this example organ – the SWELL and the CHOIR Divisions are enclosed. At the organist’s feet are “EXPRESSION PEDALS or SHOES” which OPEN and CLOSE vertical “shades” of the BOX. Opening the vertical shades allows sound out of the box, closing the shades allows less sound out! This changes the actual sound as well as the volume of the stops therein! As the shades open, the high frequencies of sound are heard emanating first, then the lower frequencies follow. The converse happens as the shades close.
COMBINATION SELECTION:
But as for the manual pulling on and off stops – there’s a solution on most modern organs (especially in the USA): The ‘Combination Piston’ and the ‘Toe Stud’… On this organ each Division comes with a compliment of Pistons and Toe Studs which are
programmable
and ‘select’ combinations of stops all at one shot. There are GENERAL combination pistons that select stops for up to all divisions at the same time. There are Divisional pistons that only select stops for their particular divisions. Often there is another ‘expression pedal’ called the CRESCENDO. This pedal is yet another way to ‘select;’ stops, this time in a controlled / step-wise manner: This, generally programmable, CRESCENDO selects STOPS to go “ON” in a progression: Usually the pedal is programmed to start with a very small number of stops (usually for all the divisions at once) and, as the pedal is ‘opened’ progressively more and more stops are selected, up to FULL ORGAN with almost ALL STOPS ON!! Great way to go from “PPP” to “FFF” in one go!! And OFF WE GO… This brief introduction to the Magnificent Music Machine touched on only a few of its mechanical, control and sound-producing aspects. Subsequent articles will begin to touch on The Art of Organ Building (what kinds of voices/stops are put where, in what divisions), and The Art of Organ Registration (what stops to select, in what combinations, in what musical circumstances). Stay tuned!
