A Cappella

The term comes from church music: Italian a cappella means "in the manner of the chapel". It first described the style of church choral music and broadened to mean any singing without instruments. Today you hear a cappella singing in church and concert choirs, barbershop quartets, gospel groups, school and college vocal ensembles, and pop-style groups that arrange songs for voices alone.

How a cappella groups work

With no instruments, the singers supply everything:

• Harmony: the parts often divide into soprano, alto, tenor and bass (four-part harmony), sometimes more.
• Bass line: in contemporary groups, a bass singer may sing low, instrument-like lines on syllables such as "dm" or "bm".
• Rhythm: some groups add vocal percussion, or beatboxing, imitating a drum kit with the mouth.
• Melody: a soloist or a section carries the tune while the others accompany on vowels or syllables.

The challenge: staying in tune

Without a piano to lean on, an a cappella group has to keep its own pitch, and over a long piece many groups slowly sink flat. To stay in tune:

1. Start from a clear reference. Groups often take their starting notes from a pitch pipe or a keyboard.
2. Listen down to the bass. Tune each chord from the lowest part upward.
3. Keep breath and energy up on descending lines, where pitch tends to sag.
4. Learn how chords like to be tuned. Experienced singers adjust some notes slightly, for example a major third a touch low, which is part of good intonation in a group.
5. Check the final pitch against the starting reference, so you know whether the group drifted.

For students

Singing a cappella is excellent ear training: you have to hear your part against the others with no instrument to guide you. Start with rounds (canon) and two-part songs, then move to three and four parts. Singing short melodies from a tonic, as in Sing Before the Model, builds the inner hearing that unaccompanied singing needs.