resonators

Many African mbiras are built with a resonator chamber as part of instrument.

An mbira's sound is somewhat soft and needs amplification to be heard in most settings where others are listening or when hosho are accompanying the mbira(s). But, because of its size, a permanently attached resonator would be impractical for the mbira dzavadzimu.

      

For amplification the mbira is wedged into a hollowed-out gourd or calabash (called a deze), which resonates and enriches the mbira's sound. The calabash is usually boiled in salted water to harden it, making ot stronger and less
breakable, as well as more resonant. The deze is usually strung with bottle caps or shells that along with the mbira's buzz snare-like in sympathy with the vibrations of plucked keys.

The player will show in this paragraph

Each key on the mbira emits a fundamental pitch and a cluster of overtones; the resonator shapes, reinforces, prolongs, and amplifies this complex tone. The buzzing bottle caps not only provide rhythm to the music's texture but also add to the instrument's array of tuned and untuned sounds. Tones overlap. The mbira's sound surrounds the player. In this music, the whole is far more than the sum of the parts.

Paul Berliner — The Soul of Mbira

Gourds large enough for an mbira are difficult to grow and are prized by mbira players. In order to resonate well the gourd must be thin and hard, and this makes them fragile and easily broken. It is not uncommon for dezes to be stitched together to keep them usable.

In recent years dezes have been made from fiberglass. These are much more durable, and hence easier to travel with. But they don't quite resonate with the clarity and depth of a natural calabash.

Played in a calabash the tone of the mbira comes alive — full-bodied, mellow, and rich. As well, the deze's shape affects the shape of the music.

As he plays interlocked polyrhythmic parts, the complexity of the mbira’s music often gives the impression of more than one instrument being performed. Musicians explain this phenomenon in part by the fact that when they strike a sequence of keys, the keys’ pitches are sustained in the gourd resonator, overlapping and intermixing. As several patterns are repeated in a cycle their beginnings and endings become ambiguous; new phrases appear in the music as one listens to the inner parts of the piece.

Paul Berliner — The Soul of Mbira