AGO Organ Registration & Tonal Design 3 — Questions and Answers
Question 1: A 'Larigot' mutation stop sounds at which pitch level?
- 2 2/3'
- 1 3/5'
- 1 1/3' (Correct answer)
- 4'
Correct answer: 1 1/3'
The Larigot sounds at 1 1/3', which corresponds to the interval of a twelfth (octave plus a fifth) above the written pitch.
Question 2: Which stop is most appropriate for accompanying a soft choral anthem on a moderate-sized American organ?
- Full principal chorus with Mixture
- 8' Flute and 4' Flute on a secondary division (Correct answer)
- 16' Bourdon coupled to Great
- Tuba with heavy wind pressure
Correct answer: 8' Flute and 4' Flute on a secondary division
A soft 8' and 4' flute combination on a secondary manual provides gentle, blending support without overwhelming a choir.
Question 3: What is the effect of 'chorus coupling' (e.g., Swell to Great) when adding it to an established registration?
- It reduces the number of sounding pipes
- It adds the Swell division's stops to the Great keyboard output (Correct answer)
- It transposes the music up an octave
- It automatically engages tremulant on both manuals
Correct answer: It adds the Swell division's stops to the Great keyboard output
A sub- or unison coupler routes the output of one division to another keyboard, effectively combining both divisions' registrations.
Question 4: In German Baroque terminology, 'Plenum' registration refers to:
- A soft solo registration using strings only
- The full principal chorus from 16' through mixtures, without reeds (Correct answer)
- All stops drawn including reeds and tremulant
- A single 8' open flue stop for continuo
Correct answer: The full principal chorus from 16' through mixtures, without reeds
The German Plenum consists of the complete principal chorus — foundations, octaves, super-octaves, and mixtures — but typically excludes reed stops.
Question 5: Which tonal family is characterized by narrow-scaled cylindrical pipes producing a thin, string-like quality?
- Principal family
- Flute family
- String (Gamba) family (Correct answer)
- Reed family
Correct answer: String (Gamba) family
String stops such as the Gamba and Salicional use very narrow-scaled cylindrical flue pipes that emphasize upper harmonics, producing a thin, stringy tone.
Question 6: What term describes the practice of gradually adding stops or sub-couplers to increase dynamic level on the swell division?
- Terraced dynamics
- Swell shading
- Registration crescendo (Correct answer)
- Harmonic reinforcement
Correct answer: Registration crescendo
A registration crescendo systematically adds stops to build dynamic level, as opposed to the swell box lid which provides continuous shading.
Question 7: On a tracker-action organ, why is heavy wind pressure less common than on electropneumatic instruments?
- Tracker actions cannot transmit electrical signals
- High wind pressure requires mechanically heavier key action, making it impractical (Correct answer)
- Tracker organs never have reed stops
- Mechanical actions are limited to 8' pitch stops only
Correct answer: High wind pressure requires mechanically heavier key action, making it impractical
Tracker action links keys mechanically to pipe valves, so higher wind pressure demands greater key resistance, making playability difficult.
AGO Organ Registration & Tonal Design 3
A 'Larigot' mutation stop sounds at which pitch level?