Guest Blog Series: #2 diastemas for marimba
…diastemas [2005-I], for marimba and electroacoustic sounds
…diastemas [2005-I] was written for Gina Ryan in response to her request for a new piece for marimba and tape. After she did the premiere performance at Pollack Hall in 1995, she has performed the piece several times. diastemas was also taken by other performers and was recorded on CD.
The tape part was realized by recording Gina Ryan's improvisations on a few musical sequences and gestures suggested by the composer. The instruments used were marimba, temple blocks and some bells, crotales and drums. The recording sessions took place at Pollack Hall, at McGill’s Faculty of Music, with Kent Walker as recording engineer. These digitized recordings were then processed using dedicated software programs on a Macintosh computer system.
diastema [Gr. interval, from 'diasté': to stand apart]. In Biology, it refers to the modified protoplasm at the equator of a cell, which exists previous to the mitotic division of the cell. Musicological studies in Iberoamerica make references to certain medieval music styles as "música diastemática". This music style, able to notate the intervallic distances with more precision, came after the notation with 'neumas'. Established around the Vth C., pneumatic notation was able to specify the exact number of notes in a melody, but was rather imprecise in terms of pitch and intervals, as well as rhythm.
The notation used in this composition is a mixture of 'proportional' and 'time' notation. It can be read with some freedom, but always using logic and common sense. Marimba and tape are to be relatively synchronized, but not exactly in synch with each other. The tape [on CD] runs non-stop from the start of the piece.
The performer plays with "Multi-tone" mallets. This allows for fast changes from pp to sff and fortissimo. The additional instruments used are: Temple Blocks and Wood Blocks  notated in the upper line, and Log Drum and Bamboo Chimes notated in the lower line. In case of chords with large intervals [9th for example], it is best to play like an appoggiatura, from the bottom up.