Multitemporal music is composed using sound streams that have different internal tempi or pulse

Pulse (music)

In music and music theory, the pulse or tactus consists of beats in a series of identical yet distinct periodic short-duration stimuli perceived as points in time occurring at the mensural level...

 speed, for example one part at 115 bpm and at 105 bpm at the same time. Multitemporal music was first heard in US-Mexican composer Conlon Nancarrow

Conlon Nancarrow

Conlon Nancarrow was a United States-born composer who lived and worked in Mexico for most of his life. He became a Mexican citizen in 1955.Nancarrow is best remembered for the pieces he wrote for the player piano...

's work, discovered by Hungarian György Ligeti

György Ligeti

György Sándor Ligeti was a composer of contemporary classical music. Born in a Hungarian Jewish family in Transylvania, Romania, he briefly lived in Hungary before becoming an Austrian citizen.-Early life:...

, who undertook the task of bringing Nancarrow's music to the fore.

To overcome the limits posed by a human performer in playing a multitemporal score Nancarrow used two modified player-pianos, punching the rolls by hand. One of the few recordings of this composer's work is found in Wergo's "Studies for Player Piano' series. The idea was then proposed by Iannis Xenakis

Iannis Xenakis

Iannis Xenakis was a Romanian-born Greek ethnic, naturalized French composer, music theorist, and architect-engineer. He is commonly recognized as one of the most important post-war avant-garde composers...

 in the early seventies and more recently by Italian born composer Valerio Camporini Faggioni using synthetic and software devices.