Free time is a type of musical meter free from musical time and time signature. It is used when a piece of music has no discernible beat. Instead, the rhythm is intuitive and free-flowing. There are five ways in which a piece is indicated to be in free time:
Examples of musical genres based around free time include free improvisation, free jazz and noise music. Examples of music written in free time include Erik Satie's Gnossienne No. 1, Charles Ives' Concord Sonata, and most of Kaikhosru Sorabji's music. Examples of contemporary songs in free time include "Hunting Bears" by Radiohead and "Lover, You Should've Come Over" by Jeff Buckley.
The usage of free time is almost absent in popular music. The Allman Brothers Band was known for occasionally dropping into free time segments on their lengthy live jams. The most famous example can be found on "Whipping Post" on the live album At Fillmore East. The band drops into a lengthy free time at the 10 minute mark, before coming back into 12/8 time about 5 and half minutes later. They drop into free time again at the 17:15 mark and continue to the end of the song at about 23:00.
Another famous example is in the nearly 10 minute psychedelic Pink Floyd composition "Interstellar Overdrive", The opening hook of the piece is a distorted, descending guitar riff played in unison by the band. This riff eventually turns into improvisation, including modal improvisations, percussive flourishes on the Farfisa organ, and quiet interludes. The song gradually becomes almost structureless and in free-form tempo, punctuated only by strange guitar noises. Eventually, however, the entire band restates the main theme, which is repeated with decreasing tempo and more deliberate intensity. The novel use of stereo (in the second mix of the album, the original being monophonic) makes the sound oscillate between speakers towards the composition's conclusion. Live versions of the song often exceeded 20 minutes.