Monaural

Monaural is a term used in audio to denote sound transmitted or reproduced using a single channel. In a monaural signal, the same audio content is sent to all loudspeakers or to both ears, producing no deliberate left–right image.

In contrast, stereo uses two channels to create spatial cues, while binaural uses two channels recorded to mimic the human ears, enabling three-dimensional impressions when listened to with headphones. This distinguishes monaural sound from arrangements that preserve or enhance directional cues.

Historically, most recordings and broadcasts were monaural until the mid-20th century. Stereo became standard for music in the 1950s and 1960s, while mono remains in use for certain applications. Today, monaural playback is common in talk radio, legacy archival material, some podcasts, and systems where bandwidth, hardware, or ease of distribution favor a single channel.

Technically, mono audio can be stored as a single-channel file in formats such as mono WAV, AIFF, or MP3 with one channel. It generally requires less data and is highly compatible with a wide range of devices. However, it lacks the spatial imaging of stereo and multichannel formats, which can reduce the sense of depth and place within a mix.

Terminology varies: monaural is sometimes shortened to mono, and monophonic is related but may be used to describe single melodic content rather than a channel concept. In contemporary production, mono is often chosen for compatibility or specific creative or practical reasons, while stereo and multichannel formats are preferred for most music and film sound.