Postal Pieces

Drone is a minimalist music genre defined by sustained tones, long durations, and extremely gradual change. Harmony is often static or centered on a single fundamental with subtle overtone shifts, while rhythm tends toward stasis or very slow pulses. Sound sources range from acoustic instruments (e.g., strings, organ, bagpipes, shruti box, tambura) to electronics (sine waves, oscillators, feedback, tape loops, and later digital synthesis and processing). Many composers favor just intonation or other alternative tuning systems to emphasize beating patterns, psychoacoustic effects, and the internal life of sound. Although drone as a sonic principle is ancient and global, the modern experimental genre cohered in the 1960s through the New York minimalists and related avant‑garde circles, then spread into ambient, experimental, and heavy music scenes. The focus is less on melody and more on timbre, resonance, and the phenomenology of listening.

Indeterminacy is a strand of post‑war experimental music in which some aspects of a composition are left to chance or to the free choice of the performer, ensuring that no two realizations are exactly the same. The approach encompasses chance procedures used during composition (e.g., tossing coins or consulting the I Ching), open or mobile forms in which sections may be reordered, graphic or text‑based notation that prompts interpretation rather than strict reading, and time‑bracket techniques that specify durations but not exact synchrony. Closely associated with the New York School (John Cage, Earle Brown, Morton Feldman, Christian Wolff), indeterminacy challenged traditional authorship, fixed works, and score‑bound precision by shifting agency to processes and performers. While often conflated with “aleatoric” music, indeterminacy typically denotes unpredictability at the level of performance/realization (open form, variable notation), whereas chance composition may use randomness to create a fixed score. In practice, many works combine both.

Microtonal classical is a stream of Western art music that organizes pitch using intervals smaller than the conventional 12-tone equal temperament. Composers employ alternative equal temperaments (such as 19, 24, 31, or 72 tones per octave), just intonation, and other tuning systems to expand harmony, melody, and timbre beyond the familiar semitone grid. The genre foregrounds novel intervals, complex chordal spectra, continuous pitch (glissandi), and fine-grained intonational nuance. It can sound otherworldly, tense, or delicately shimmering, and often requires specially retuned instruments, extended techniques, or custom-built instruments to realize its pitch language.