monoaural

Monaural refers to sound that is perceived by only one ear. This contrasts with binaural sound, which is designed to be heard with both ears and often aims to simulate the natural way humans experience sound. Monaural sound typically originates from a single source or is processed in a way that all sonic information is combined into a single channel.

In audio recording and playback, monaural (often shortened to mono) means that the audio signal is not separated into left and right channels. When played back through stereo speakers or headphones, both speakers will output the exact same audio signal. This was the standard for early recordings before the development of stereo sound. While stereo offers a wider soundstage and a sense of spatial positioning, monaural sound has its own applications.

Monaural audio can be useful in situations where precise spatial localization is not a priority, or even to deliberately avoid it. For example, some older recordings are intentionally monaural. In certain broadcasting scenarios or for assistive listening devices, a monaural signal might be preferred for its simplicity and to ensure that all listeners receive the same audio information regardless of their listening setup. Some musicians and sound engineers also choose to mix in mono to ensure their music translates well across various playback systems, as many car stereos or small speakers default to a mono or near-mono output.