A cappella
Vocal music without instrumental accompaniment.
What it means
A cappella denotes vocal music without instruments. The expression comes from church music and originally meant the manner of performance in the chapel — that is, the style of sixteenth-century polyphonic sacred music. Today it is used quite generally, from choral music through vocal ensembles to popular singing groups. What is always meant is that everything heard is produced by voices — including the bass line and the accompanying figures.
Musical use
Without instruments the responsibility shifts: the singers must hold pitch, harmony and time on their own. From this follows a special attention to intonation, for a choir without support can sink or rise over the course of a piece. At the same time the scoring opens up freedoms: just intonation can be produced directly, because no equal-tempered instrument stands against it, and chords can blend completely in sound. The repertoire ranges from the Renaissance, in which this manner of writing reaches its peak, through Romanticism and into the present, and encompasses both sacred and secular music.
Performance practice
Attend to a clear reference pitch at the start, and to keeping it not only in your ear but inwardly. As you sing, listen to the neighbouring voices more than to your own; intonation arises from the combined sound, not from the single line. Keep the thirds in major chords rather low and leading tones rather high, and practise chords slowly as sustained sonorities. Watch for uniform vowel colours, because differing pronunciation splits the sound. Plan breathing points together and agree where to stagger the breath, so that long lines do not break off.
Reckon with a choir sinking over the course of a longer piece; this usually has to do with slackening bodily tension and with leading tones taken too low, not with faulty hearing. It helps to think the tonic of a passage inwardly now and then, and to practise difficult chords beforehand as sound. In rooms with little reverberation you need more clarity in the consonants, in reverberant ones more calm in the tempo. A brief tuning note between movements is not a weakness but prevents deviations from carrying on across a whole programme.