Lo-fi, a contraction of low fidelity, began as the opposite of hi-fi: a description of recordings that sounded cheap, noisy or home-made. Over time the imperfections themselves became something listeners valued. The musicologist Adam Harper, in a 2014 doctoral thesis at the University of Oxford, describes lo-fi as an aesthetic built on a positive appreciation of what would normally count as flaws in a recording.
The label spread in the late 1980s, helped by the WFMU radio presenter William Berger, whose show was devoted to home recordings, and became a recognised indie style in the 1990s with artists such as Pavement, Sebadoh, Guided by Voices and Beck. Affordable four-track cassette recorders, from the Tascam Portastudio of 1979 onwards, made that home-made sound possible.
Today the word is most often shorthand for lo-fi hip hop and its relatives, including the jazz lo-fi featured on Mondolofi, where tape hiss, vinyl noise and softened high frequencies are added on purpose to make a track feel warm and close.