Program Notes

John Holland


for Computer-controlled Synthesizers Nos. 1-24 (Enhanced 2012 Version)


Etude No. 17 (visualization by Ron Wallace)

The 24 Etudes contain sounds which are traditionally associated with keyboards, including the harpsichord, organ, accordion, piano, celeste, and synthesizer. In addition, the music simulates various timbres of different keyboard instruments, including sounds which are evocative of struck and plucked strings, bell-like tones, and percussive effects.

Modern uses of the keyboard are referred to in different Etudes, such as quarter-tone music, various percussive effects, prepared piano, pedal techniques, and the use of piano strings as a solo instrument.

All of the Etudes are generated by the computer in real-time. Each Etude is realized according to a separate computer program containing specific instructions to realize the music. The decisions made by the computer are based on a combination of determinist and random means which simulate the general flow of dynamic systems and patterns in nature.

The Etudes consist of the juxtaposition of the simplest elements of musical texture (pitch, dynamics, duration, speed, rhythm, articulation, etc.) combined with simple structural elements (continuity, repetition, variation, and chord structures which are derived from the melodic flow of the music).

Each Etude focuses on a fundamental element of musical texture or structure. An Etude may contain sound-groups which are high or low, loud or soft, legato or staccato, fast or slow, accelerating or decelerating, short or long, rhythmically regular or irregular, dense or sparse. One Etude consists of sound-groups containing regular rhythms played at different speeds, while another contains irregular rhythms produced at a slow speed. One Etude contains varied repetitions only, while another is based strictly on ascending and descending patterns. Some Etudes combine many elements of texture with a single structural element, while others are structured in the opposite way.

The original music for all of the Etudes was produced on the DX7s keyboard synthesizer and two TX81Z tone-generators, operating in combination. The computer programs were written in C language on a Macintosh SE computer. All of the music was recorded digitally. In 2012, I added a variety of synthesizer sounds to the original Etudes, often coupling them together, to give the pieces a broader musical texture.

– J. H.

Etude No. 20 (original)

Etude No. 20 (visualization by Ron Wallace)


  J. S. Bach


The Musical Offering (Musikalisches Opfer, BWV 1079, is a collection of keyboard canons and fugues and other pieces of music by Johann Sebastian Bach, all based on a single musical theme given to him by Frederick the Great (Frederick II of Prussia), to whom they are dedicated. The Ricercar a 6, a six-voice fugue which is the highpoint of the entire work, was put forward by the musicologist Charles Rosen as the most significant piano composition in history (partly because it is one of the first).[1] This ricercar is also occasionally called the Prussian Fugue, a name used by Bach himself. The composition features in the opening section of Douglas Hofstadter’s Pulitzer Prize winning book Gödel, Escher, Bach (1979).