Lo-fi (also typeset as lofi or low-fi; short for low fidelity) is a music or production quality in which elements usually regarded as imperfections of a recording or performance are audible, sometimes as a deliberate aesthetic choice. The standards of sound quality (fidelity) and music production have evolved throughout the decades, meaning that some older examples of lo-fi may not have been originally recognized as such. Lo-fi began to be recognized as a style of popular music in the 1990s, when it became alternately referred to as DIY music (from "do it yourself").