That choral music owes much to Robert Shaw cannot be disputed. Surprisingly, though, one of the areas where his unique creativity was the most apparent was in the often-neglected field of the choral warm-up.

For many conductors, the warm-up period—when used at all—is a time devoted only to vocalizing the singers. With Shaw, the warm-up was something else entirely. It was during this brief portion of the rehearsal that his singers developed—in microcosm, if you will—the art of being an ensemble.

Believing that the chorus was a corporate entity with a spirit of kinship, Shaw used the warm-up period to focus all of those individual minds on matters of tuning, tone color, ensemble blend, acoustical conditions, and development of the dynamic palette. His belief was that his role was not that of a studio voice instructor, so it would therefore be an inappropriate use of his singers' time to lead them through an array of generic vocal exercises. Rather, each singer was expected to vocalize independently prior to rehearsal, so that the warm-up time could be used to "tune" the ears and the brain. For Shaw, this was the time to establish the disciplines so crucial to the ensemble's maturation into a truly expressive musical instrument.

Making Warm-Ups Relevant

Shaw's warm-ups were effective not only because of their pedagogical soundness, but also because of their utter relevance to the rehearsal. They remain an integral part of all of my rehearsals, regardless of the age level of the singers. Because I'm dealing with student singers, however, my warm-up periods include more basic vocal exercises—breathing exercises and vocal warm-ups that focus on all areas of the basic technique—in addition to warm-ups selected from those that Shaw utilized. From beginning to end, the warm-up process takes roughly ten minutes—they are, however, the most important ten minutes of the rehearsal.

Below are the exercises Shaw used—notated and in audio. The exercises are listed roughly in the order in which he would use them—although he would never have used all of them in a single warm-up period. Each was chosen for its relevance to the rehearsal (or performance) ahead, taking into consideration repertoire problems and demands, acoustical issues, and the ensemble itself.

Shaw constantly "tweaked" the exercises, changing them somewhat to fit the needs in the rehearsal ahead, but also possibly just to keep the singers from becoming too complacent or thoughtless in their approaches.

The Warm-Up Exercises

Shaw asked the chorus to sing all of these exercises substantially without vibrato in order to produce the purest possible sound. In a mixed chorus, an interesting by-product of this will be the clearly audible overtones that are generated when singers achieve finely tuned octaves (the most evident overtone being the pitch that is a perfect fifth above the treble voices).

Shaw also maintained that immaculate tuning and the reinforced overtones generated by an ensemble that took such great care with intonation would produce a healthier, more vital choral tone. Theoretically, a smaller chorus that follows these principles of tuning might generate a more full-bodied sound than a much larger ensemble that does not develop similar disciplines.

For each exercise, only the beginning pitch is suggested. If you're working with a chorus, or with yourself, you may wish to continue the exercises by moving up or down by semitones (Exercise 7 is the only possible exception—the pitches indicated seem to be the most suitable, given the extremes of ranges that are demanded).

Vowel Unification

1. A single pitch, sung in unison (or octaves) on the nonsense syllable, "noo." Begin on a moderately low pitch, such as E, and move down by semitones. This exercise allows the singers to concentrate on nothing more than basic vowel unification and tuning.

2. A variation of Exercise 1 is to sing through a series of vowels (generally moving from closed to open vowels). The singers should be asked to concentrate on maintaining their unison while progressing through each successive vowel shape. As they sing the more open vowels, they should be cautioned to avoid a) allowing the dynamic to suddenly become louder and b) allowing the pitch to drop.

Divisi Textures

3. Two, three, then four pitches sung on "loo" or "noo," creating a whole tone cluster. Singers may also sing on "nee" or "naw" or move from "nee" to "aw." This exercise is useful for determining balance issues in two-, three-, and four-part divisi textures. In addition, the dissonance created by the cluster pitches is preferable to more consonant intervals because one can more readily determine if one voice part is overbalancing the other voice parts.

Intonation

These exercises are especially useful in establishing discipline in the area of intonation. Shaw would jokingly admit that raising the pitch one-sixteenth of a semitone at a time was probably not possible. Nevertheless, the singers would eventually learn how to move gradually up (or down) in extremely small degrees—and maintain a unison throughout. (Note: when working with a mixed chorus, octave unisons between the sopranos/tenors and altos/basses should be maintained even as they are moving through the series of subtly-changing pitches).

4. Beginning on a moderately low pitch such as E, move up a semitone in 16 pulsed unison pitches (effectively dividing the semitone into 16 separate notes, with each sung almost imperceptibly higher than the last). For even more intensive ear training, a minor third relationship between lower and upper voices may be used.

5. A variation of Exercise 4 is to have sopranos and tenors ascend a semitone, while altos and basses descend a semitone, ending a whole tone apart.

6. Another variation is to sing Exercises 4 and/or 5 in one long sustained 16-beat "note."

7. "Noo-ah" exercise. This is highly effective not only for developing the ears and brains in matters of intonation, but also for achieving unanimity of line throughout and between vocal registers. Singers should be encouraged to control the vowel shape and the dynamic when moving from the "oo" to the "ah" vowel, so that the secondary vowel does not "pop" out too suddenly. Singers who tend to carry too much weight from lower to upper registers will eventually learn how to maintain a more consistent tone color as they sing larger intervals in higher registers.

According to Shaw's former assistant, Norman Mackenzie, the exercise ascends by semitones and descends by whole tones (concluding with the major 3rd relationship) for several reasons:

To reinforce ear-training by using different intervals for ascending and descending, thereby causing the singers to think more carefully.

To more easily find the next starting pitch/interval (because of the harmonic relationship).

As Shaw said with tongue in cheek, "to make the exercise somewhat shorter."

Note: The final version (in common, or 4/4 time) should be sung with tenors doubling sopranos at the lower octave and basses doubling altos at the lower octave.

Changes in Acoustics

Exercises 8, 9, 10 and 11 place the singers in the position of preserving correct intonation while constantly changing their acoustic. For instance, when a singer turns around in a circle, he or she is singing into an ever-changing reflective surface, forcing him or her to listen acutely in order to maintain a consistent pitch. A similar result may be achieved by asking singers to face the nearest wall of the shell (or room). In both instances, ears and minds are forced to make minute, instantaneous adjustments in order to maintain accurate pitch, tone color, and balance. Shaw maintained that this was the fastest way for singers to become accustomed to new acoustical environments.

8. Beginning with a unison pitch on "noo" or "nee," change vowels rapidly ad lib while slowly turning 360 degrees.

9. Move from "noo" to "ah" and at the same time, crescendo from a soft to a full dynamic. Do the same with each singer facing the nearest wall. A variation is to turn 360 degrees while continuing to crescendo.

10. Another variation of Exercises 8 and 9 is to use whole tone clusters or minor thirds (with basses doubling altos and tenors doubling sopranos).

11. Yet another variation of Exercise 9 is to add too much vibrato once the dynamic level reaches forte, thereby distorting the pitch. Then repeat the exercise and add just enough vibrato to warm the pitch. Since this particular exercise is intended to develop an awareness of tonal consistency, singers should not be asked to turn 360 degrees. Rather, they should face forward so that they can maintain a consistent acoustical surrounding.

Tone Color

Exercises 12 and 13 are useful in developing an awareness of the variety of tone colors available to the choral ensemble. Note: a minor third or whole tone cluster may be used in place of a unison pitch.

12. Begin with unison pitch on "nee" with an overly bright vowel. Crescendo and darken the vowel. Do the exercise again, beginning with a tone that is too dark, gradually brightening the vowel during the crescendo.

13. A variation of Exercise 12 is to begin dark and as the choir grows louder and brightens the vowel, open to "ah" while continuing the crescendo.

Dynamics

14. Measuring crescendos and diminuendos. This exercise is crucial to developing an ensemble's awareness of its own dynamic palette. If a chorus can establish levels of dynamic intensity in an isolated manner, it will be much more adept at achieving healthy and appropriate levels of dynamic contrast within the musical texture.

On a unison pitch, using the syllable, "nah," crescendo from piano to forte over a period of eight beats. Then, begin forte and decrescendo to piano for eight beats.



Instead of a unison pitch, use a minor third (with basses doubling altos and tenors doubling sopranos) or any combination of more than one pitch.



Using either a unison pitch or more than one pitch, have sopranos and altos begin forte, while tenors and basses begin piano. Then, have the chorus sing eight-beat crescendos or decrescendos (depending upon the beginning dynamic), continuing for several counts of eight.



Robert Shaw believed that, in terms of rehearsal disciplines, the chorus was not much different from the orchestra. Skills were layered one element at a time—as each new element was added, the previously taught elements were further reinforced. He maintained that attempting to teach everything at once would most likely lead to a confused and imprecise product where the music was not allowed to be heard in a truly honest fashion. He employed the same philosophy when it came to the warm-up, and the result was that his singers gradually began to assume responsibility for all matters having to do with the interpretation of repertoire. We should expect no less from our own choirs.

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A longer version of this article first appeared in 2003 on the website of the Association of British Choral Directors. The author would like to thank the following for their input into this project: Thomas Shaw, Robert Shaw's son; Nola Frink, former administrative assistant to Robert Shaw; Norman Mackenzie, former musical assistant to Robert Shaw and currently the director of choruses for the Atlanta Symphony Orchestra; Ann Howard Jones of Boston University; Susan Brumfield of Texas Tech University; Thomas Hughes of Texas Tech University; John Dickson; and the 2003 Texas Tech University Choir.