Spectrum" is an attractive four-mallet marimba solo by marimbist Daniel Berg. Similar to his popular composition, "Over the Moon," "Spectrum" creates a collage of uneven rhythms and shifting harmonies that slowly envelop the listener. According to the composer, "Specturm" is similar to a prism. Berg hopes that the audience will hear "different sources of inspiration" in this prsim such as "rhythms from the Japanese marimba virtuoso Keiko Abe and harmony from the music of genius Quincy Jones."While no meter is indicated for "Spectrum," Berg writes in 7/8 or 5/8 much of the time. The glue that holds the music together is a left-hand ostinato that primarily shifts by half-steps or whole steps. Meanwhile, the right hand performs a pleasant melody that gradually increases the tension both harmonically and rhythmically. The six-minute composition eventually returns to a variation of the original theme before concluding softly. "Spectrum" would be a fine choice for any intermediate- to advanced-level marimbist. The music is charming and suitable for any recital or concert.--
Mark Ford, Percussive Notes -- April 2009