Use of rhythm in twentieth-century music is varied. Composers strive to achieve a variety of rhythmic accents and groupings. Intricate rhythm patterns are usual. Twentieth-century composers use rhythm as a means of achieving tension. Many composers utilize changing meters to achieve rhythmic variety and excitement. Choral composers often use this technique in an attempt to create a musical inflection of the text. Constant meter changes are not unusual. Each use must be examined individually; no one solution can be applied to all occurrences. The conductor must determine the simplest and most direct method of realizing the intention of the composer.

Tempo is related to the musical style and mood of the text. Extremes in tempo are frequently found. Tempo changes are often abrupt and require skillful handling by the conductor. Composers mark their scores carefully and use metronome markings to indicate the tempo they prefer. A conductor should respect these markings and consider them as guidelines to their performance tempos. Of course, he must also consider the performance hall acoustics, ensemble size, and performers.

Many and varied textures are demanded in twentieth-century choral music. There has been an interest in chamber choirs by composers. This is both a reaction against the gigantic forces used by the later nineteenth-century composers, and a practical consideration utilizing smaller groups to perform complex scores. Each score must be examined carefully regarding texture. Impressionistic and post-romantic music usually involve a vertical structure whose harmonic movement is fluid, with an emphasis on harmony and beauty of tone. Twelve-tone scores are more horizontal and less emphasis is placed on individual chords. Its dissonance demands a tone quality with a minimal vibrato. Additionally, the singers must be thoroughly skilled in the singing of intervals to learn and perform this repertoire.

Twentieth-century composers often utilize a number of textures and moods within one work, changing both texture and mood often. Wide variations in tone quality will be necessary to make these changes effective. Although most of the choral music performed is only mildly dissonant, more avant-garde music is finding its way into performance halls. Electronic music is not really new, but music for prepared tape and chorus has only recently been accepted by most choral conductors (and performed by only a modest percentage of those).

Aleatoric (indeterminate or chance) pieces are performed by the more adventurous conductor. Works that are considered avant-garde are likely to require anything from a normal singing tone to whistling, whispering, and other assorted vocal sounds.

More textural possibilities exist today than ever before. The choral conductor may find music for chorus and many instrumental combinations that substantially expand the texture. It is the conductor's responsibility to understand the tonal and textural requirements of each work and to determine whether or not his ensemble can meet these requirements. Not every choir or conductor will be able to successfully meet the performance requirements of each work.

The dynamic range is even wider than that of the Romantic period since it now includes whispering, singing as loud as one can, and even yelling. Sudden changes in dynamics are also more numerous than ever before. Many works even require a dynamic scheme that changes on every count of the measure for several measures. It is quite usual to find different dynamic indications in different parts on the same passage. For example, the composer may wish the tenors and sopranos to be prominent and will mark them forte while the bass is marked mezzoforte and the alto, piano. Although this type of dynamic scheme is not entirely new, it is used more frequently by twentieth-century composers.

Twentieth-century choral music requires many different tone qualities. Less than other periods, no one choral tone will suffice. It can be said that a tone with a minimal vibrato is often used because of the numerous occurrences of small intervals and the overall dissonance of the music. It should be said that a tone without vibrato should be used when specifically requested by the composer. A tone without vibrato use sparingly and momentarily for specific artistic and composer demanded instances is quite accaptable. When a "straight tone" is used indiscriminately the choral tone becomes lifeless and uninteresting. A vibrato in the singing voice is quite natural and creates a buoyancy and virility in the tone otherwise absent.

Specific types of tone quality are occasionally requested by composers. Conductors will find such requests as "with a full, rich tone," "sing with a thin, white tone," or simply "senza vibrato" in scores. This is a result of a composer wishing to achieve a certain sonority usually prompted by the text.

Since the 1950s, composers have incorporated aleatoric aspects into their compositions. Many works are published that combine traditional and non-traditional notation. The problems that face the conductor of much new music are:

1. Determining the meaning of the notation (when nontraditional)

2. Convincing the choir that the new sounds are valid musical choices

3. Achieving a thread of continuity through a work that utilizes several twentieth-century techniques

Each new work must be thoroughly examined to understand the composer's intent. This is true of all music, of course. Every new work may have its own particular notation unlike any other piece, even another by the same composer. New notation follows only such rules as the composer may apply to a specific work. There is no standard, although a few notational features are being used consistently by a number of composers to mean the same thing. This use is approaching a standard and one will eventually be set. Usually composers place an explanation of their notation in a foreword to the score. Performance suggestions are likely to be included.

It is most important that the conductor have the complete confidence of his choir in order to successfully perform aleatoric music. The conductor must also accept the music as being valid and be willing to work as hard on that music as he would on any traditional piece. The rehearsal planning will be different but nonetheless important. (See chapter two for a discussion of score analysis of aleatoric music.)

Music for prepared tape and choir has become plentiful recently and has received a number of performances. As with all music, the quality of these works varies and conductors must judge each work on its own merits. Several works will no doubt become "standard" pieces in the choral repertoire while others will be discarded. More of these works were composed in the 1970', 1980s' and early 1990's than now, it seems at least by the performances. However, there are composers experimenting with a variety of electronic means, voices and other instruments.

Conductors should be cautioned about use of tape and voices together. Unless a certain quality is specified by the composer, a full singing tone should be employed. The tone should be vibrant, containing a minimal amount of vibrato, and not be an attempt to mimic the electronic sounds. The composer is aware of the natural qualities of the human voice and wishes to capitalize on the difference between the voice and the taped sounds. He does not expect one to sound like the other, except where carefully specified.

Another important consideration is the quality of playback equipment. In general, the quality of playback equipment has improved greatly, is more diverse with excellent systems while the price has diminished.

Collect (with electronic tape), Bassett (World Library of Sacred Music) Nine Choral Fragments (Aleatory), Childs (Keynote Music Co.) All the Ways of a Man, Nystedt (Augsburg Pub. Hse.) Carols of Death, Schuman (G. Schirmer) Rejoice in the Lamb, Britten (Boosey and Hawkes) Christmas Cantata, Pinkham (Robert King Music Co.) Aleatory Psalm, Lamb (World Library of Sacred Music) Magic! Magic! Magic!, Kubik