Improvisation is music invented in the moment of performance rather than read from a score or played from memory. In jazz it usually happens inside a framework: soloists create new melodies over the chord progression and form of a tune, drawing on scales, rhythms and phrases they have absorbed, while the rhythm section improvises its own accompaniment. Britannica stresses that jazz is not improvisation alone, since composition, arrangement and ensemble playing have always mattered too, and notes that before about 1925 few musicians could play long, independent improvised solos.
Improvisation reaches jazz lo-fi in two ways. Many tracks sample improvised passages from older jazz and soul records, and many producers record their own loose keyboard or guitar takes, keeping the moments that feel natural. The result is often a mix of fixed loops and small spontaneous gestures.