Tension and Release is an often used term for analyzing music, to describe how music keeps the interest of a listener. In Western tonal music, ranging from European classical music to modern pop, tension is often thought to derive from the dominant chord. Release is said to occur when the music then reaches the tonic

Tonic (music)

In music, the tonic is the first scale degree of the diatonic scale and the tonal center or final resolution tone. The triad formed on the tonic note, the tonic chord, is thus the most significant chord...

 chord or "one chord" based from the first scale degree of the key.
In atonal music or improvised music, such as free jazz

Free jazz

Free jazz is an approach to jazz music that was first developed in the 1950s and 1960s. Though the music produced by free jazz pioneers varied widely, the common feature was a dissatisfaction with the limitations of bebop, hard bop, and modal jazz, which had developed in the 1940s and 1950s...

 or jam band

Jam band

-Ambiguity:By the late 1990s use of the term jam band also became ambiguous. An editorial at jamband.com suggested that any band of which a primary band such as Phish has done a cover of be included as jam band. The example was including New York post-punk band Talking Heads after Phish performed...

 music, harmonic progressions are not necessarily recognizable, but audiences still often perceive suspense and resolution, closely related to the concepts of tension and release, respectively.

Seen in terms of its phenomenology for the musician performing an improvisation

Improvisation

Improvisation is the practice of acting, singing, talking and reacting, of making and creating, in the moment and in response to the stimulus of one's immediate environment and inner feelings. This can result in the invention of new thought patterns, new practices, new structures or symbols, and/or...

, this experience can be attributed to different temporal relationships between a musician's cognitive perception of the notes played and the physical sounds from the instrument. If the musician is internally choosing the notes to be played a moment before each note is actually played, this tends to involve an active assertion of the will on the course of musical choices and will often be perceived as a kind of tension. By contrast, if a musician takes a less active role in choosing new notes, but simply repeats the same pattern while effectively only listening to the sounds after they are played, this can create a sensation of release.