 |
|
|
|
|
Celebrating the pipe organ, the King of Instruments |
Mailbag: Stop lists
February 13, 2006
Dear Michael:
I have been a church organist for nearly 50 years, I don’t know the meaning of (TC) appended to a cornet, celeste or reed in a stop list.
Help! Norman Thompson
Newark, DE
Dear Norman:
Organ ‘specifications’ (stop lists) can be confounding. For the layman, the names may make the most direct sense (Octave, Rohrfulte, Krumhorn), as they represent colors and characters.
The Arabic numerals are sensible, too, when you realize that the 8′ designation relates to pitches equivalent to (and in unison with) those on a piano…the pitch of middle “c” on an 8′ organ stop is the same as middle ‘c’ on the piano. The designation evolved because the bottom ‘c’ on an organ keyboard plays an open pipe with an actual speaking length of 8-feet from mouth to top.
As you play up the keyboard to higher pitches, pipes get shorter, becoming half-as-long with each octave advance. Thus, the other numbers represent ratios of that unison pitch 8′: 4′ stops play an octave above unison, 2′ stops are two octaves above unison, 2 2/3′ stops are an octave and a fifth above unison (sounding the note ‘g’ when the finger is on ‘c’), etc. You do the math.
The Roman numerals (III, VI, V-VIII) represent stops with multiple ranks that sound simultaneously when a single key is depressed. These high pitched ‘mixtures’ strengthen and enhance an organ’s chorus.
In the case of a Cornet V (TC), we have one stop which activates five ranks of pipes. Press one key and five pipes sound per note. The ‘recipe’ for the Cornet (pronounced cor-NAY) is, at bottom ‘c’:
8′-4′-2 2/3′-2′-1 3/5′… C1-C2-G2-C3-E3. These are flute pipes which do not sound like flutes but, in this combination, blend together into a pungent new tone, almost reed-like.
The (TC) designation incidates that this stop plays only from ‘Tenor C’ upwards…there are no pipes below the TC pitch, since the Cornet was designed to corroborate and strengthen the upper pitches of actual reed stops (which are plenty powerful in their bass register) and also to act as an eloquent solo sound.
Since the individual pitches of the Cornet begin to separate out in the lowest octave of the keyboard (one hears all five notes, rather than the blend, a quality less than totally beautiful as a solo but still an interesting effect), and because those bottom notes would be represented by large and expensive pipes, tradition ends the Cornet at Tenor ‘c’ (or sometimes Tenor ‘f’.)
Similarly with the Celeste, the bottom octave of pipes it omitted, since the effect of a celeste (always played in combination with another, full-compass string stop) is more noticeable above that bottom octave so, as a cost-saving, those last 12 notes are often omitted, though not always.
I hope this is somewhat clear.
jmb
