Cool jazz emerged in the United States in the late 1940s as a calmer counterpart to bebop. Its players favoured light tones with little or no vibrato, middle registers, careful arrangements and a restrained, understated rhythm section. The tenor saxophonist Lester Young, with his airy sound and relaxed phrasing, is often seen as its forerunner.
A key starting point is the nonet led by Miles Davis that recorded for Capitol in 1949 and 1950, with arrangements by Gil Evans and Gerry Mulligan among others; the sessions were later collected as Birth of the Cool. In the 1950s the style became associated with the West Coast, including Mulligan’s pianoless quartet with the trumpeter Chet Baker, and with the Dave Brubeck Quartet, whose Time Out (1959) explored unusual time signatures. The soft sound, gentle swing and intimate mood of cool jazz are very close to what jazz lo-fi tries to evoke.