Black Key Euphony is an experiment in five-tone music performed on koto and kalimba. The five-tone scale (the pentatonic scale, for those who like jargon) forms the black keys on the keyboard: that's C#, D#, F#, G#, and A# for liberals or D-flat, E-flat, G-flat, A-flat, and B-flat for conservatives. The scale imposes challenging limitations. For example, from the seven different tones in a traditional octave we can form 35 different three-note chords, but a five-tone scale allows only 10. The CD explores what can be done under such limitations.
The music on Black Key Euphony contains 24,170 notes; every one originates from a black key on a keyboard.
Performances on Black Key Euphony are confined to two instruments: koto and kalimba, though a given set may call for multiple kotos or kalimbas or both.
The koto is a Japanese zither of 13 strings. The wooden sounding board is long, narrow, and curved--reminiscent of the earliest kotos, which were constructed from bamboo. The instrument may be as long as six feet, so it is placed directly on the floor or on a slightly raised stand or platform. All strings are the same length and are stretched to the same tension between fixed bridges. Each string is tuned by its own movable bridge. Sound is produced by plucking the strings with the thumb and first two fingers of the right hand; either bare fingers or plectra may be used. The left hand may press or otherwise manipulate the string on the other side of its bridge. Here's a link to all things koto: Koto no koto.
The kalimba is a hand-held percussion instrument from central Africa. It uses a wooden box or a gourd as the resonator; a sounding board lies across the box and a bridge is attached to the board. To the bridge are attached strips of metal of various lengths; these metal keys are fabricated from spring steel. The keys lie parallel to the sounding board; typical instruments have either 13 or 17 keys. Sound is produced by depressing and releasing the free ends of the keys; this is commonly done with the thumbs, so the instrument is also called a thumb piano. Here's a link to a dealer's pictures: Kalimba Photo.
The sound from a kalimba is rich, as it has components from the vibration of the metal strips, vibration of the sounding board, and vibration of the gourd or wooden box. The distribution of harmonics among these three components determines the timber of a particular note; the timber is also affected by the size of the instrument and the position of the particular note on the scale. At high registers, the vibration of metal dominates the sound; at middle registers, the sound is dominated by the vibration of the sounding board. This richness complements the rather sterile sound produced by the koto.