Persepolis

Stochastic music is a 20th‑century avant‑garde approach in which musical parameters are governed by probability theory and random processes rather than fixed, note‑by‑note determination. Instead of traditional melody and harmony, composers shape "sound masses" by controlling statistical features like density, event rate, pitch distributions, durations, and dynamics. Typical tools include Gaussian, Poisson, and Markov processes, which create evolving textures, swarms, and clouds of sound—often realized in both orchestral and electroacoustic settings. The term is most closely associated with Iannis Xenakis, who formalized the method and demonstrated it in landmark works and writings, but it has deeply influenced computer music, experimental electronic practices, and later microsound/granular approaches.

Tape music is a form of early electronic and electroacoustic composition that uses recorded sounds on magnetic tape as the primary material. Composers assemble, cut, splice, loop, reverse, and vary the speed of tape to sculpt timbre, rhythm, and form, often transforming everyday noises into abstract musical structures. Emerging from post–World War II studio experimentation, it blurred the line between composition and sound design. Works are typically fixed-media pieces intended for loudspeaker playback rather than traditional performance, privileging timbral exploration, spatial projection, and montage over conventional harmony and meter.

Acousmatic music is a form of electroacoustic composition created specifically for loudspeakers, where the audience hears sounds without seeing their sources. The genre privileges timbre, morphology, and spatial movement over traditional melody and harmony, and it is often experienced in darkened auditoria to sharpen attention to pure listening. Composers typically work with recorded or synthesized sounds—ranging from environmental recordings and instrumental fragments to purely electronic textures—then edit, transform, and organize them into a fixed medium. Performance focuses on diffusion: the live projection of a fixed track across a multichannel loudspeaker array to sculpt space and perspective in real time.

Electroacoustic music is a broad art-music tradition that integrates recorded acoustic sound and electronically generated or processed sound into coherent musical works. It privileges timbre, gesture, texture, and spatialization over conventional melody-and-harmony song forms, often employing tape manipulation, synthesis, live electronics, and computer-based signal processing. Works are frequently composed for fixed media (stereo or multichannel loudspeakers) and may also involve live performers who are transformed in real time. Concert presentation typically emphasizes spatial diffusion and immersive listening, and the repertoire spans concert works, radio pieces, installations, and soundscape compositions.