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Ensembles are created by combining stops. Two factors are always to be considered:
tone quality and pitch. Ensembles begin with a few stops at the 8’ and/or 4’ pitch and
expand “outward” in pitch as they build up. New pitches are usually added in preference
to another 8’ stop.
Ensembles are generally divided into three tonal groupings or “choruses”:
The Principal chorus is the most fully developed with representation in
various divisions of the organ and at every pitch from 16’ (Diapason) to high
mixtures. The Principal chorus is sometimes called the narrow-scale flue
chorus, a reference to the relative thinness of Principal pipes in relation to
their length.
The Flute chorus is also well represented with a diversity of stops at various
pitches. Generally speaking, the Flute chorus is composed of less
harmonically developed tones, and is smoother and of lesser volume than the
Principal chorus. The Flute chorus is sometimes called the wide-scale flue
chorus, owing to the generally “fatter” look of flute pipes as compared to
principals.
The Reed chorus includes those reed tones designed to be used in the
ensemble buildup. Not all reed voices are ensemble tones. An Hautbois, for
example, is usually a solo stop. The various Trumpets, Clairons, Bassons,
etc., are usually ensemble voices that add brilliance, power, and incisiveness
to the sound. If you have questions as to whether a specific reed is a solo or
ensemble stop, refer to the stoplist in Section I.
The Swell Reed chorus of Basson 16’ and Trompette 8’ represents an entity important to
French organ music and the full ensemble of the organ. These stops create a “blaze” of
richly harmonic sounds that top off both flue choruses.
Another special ensemble combination important in French music is the Cornet, which
was discussed in the section on Solo Registration. This combination can be used with the
chorus reeds and mutations to create the “Grand Jeu.” The Cornet is also useful in
Romantic ensembles to add weight and thickness to the sound.
Here are typical ensemble combinations for the Swell and Great manuals:
Great
1. Rohrflöte 8’, Spitzflöte 4’
2.
Rohrflöte 8’, Spitzflöte 4’, Superoctave 2’
