Monaural

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Label for 1.0 sound, mono.

Monaural (often shortened to mono) sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or, in the case of headphones or multiple loudspeakers, they are fed from a common signal path, and in the case of multiple microphones, mixed into a single signal path at some stage.

Monaural sound has been replaced by stereo sound in most entertainment applications. However, it remains the standard for:

Radiotelephone communications.
Telephone networks.
Induction loops for use with hearing aids.

[edit] History

While some experiments were made with stereophonic recording and reproduction from the early days of the phonograph in the late 19th century, until the second half of the 20th century monaural was the rule for almost all audio recording.

Monaural sound is normal on:

Phonograph cylinders
Disc records, like 78 rpm and earlier 16 2/3, 33 1/3 and 45 rpm microgroove.
AM Radio

Incompatible standards exist for:

Later records (monophonic records, which had almost disappeared by 1968, could be played with a stereo cartridge, but not the other way around).
Reel-to-reel audio tape recording (Depending on track alignment)

Compatible monaural and stereophonic standards exist for:

MiniDisc
Compact audio cassette
FM (and in rare circumstances AM) radio broadcasting
VCR formats (NICAM Stereo)
TV (NICAM Stereo)

No monaural standard exists for:

At various times, artists have preferred to work in mono, either in recognition of the technical limitations of the equipment of the era or due to a simple preference. This can be seen as analogous to film makers working in black and white. Some early recordings such as The Beatles Please Please Me were re-released in the CD era as monophonic in recognition that the source tapes for the earliest recordings were two track, with vocals on one track, instruments on the other, and this was actually intended to provide flexibility in producing a final mono mix, not to actually provide a stereo recording, although due to demand, this was done anyway and the early material was available on vinyl in either mono or stereo formats. In the 1970s, it was common in the pop world that stereophonic versions of mono tracks were generated electronically using filtering techniques to attempt to pick out various instruments and vocals, but these were often considered unsatisfactory due to the artifacts of the conversion process.^{[citation needed]}

Woody Allen and Stanley Kubrick both shot in mono because of personal preferences. Until Eyes Wide Shut, which used 6-track stereo (for use in an array of speakers behind the screen), Kubrick's only stereo film was 2001: A Space Odyssey.

Monaural LP records were eventually phased out and no longer manufactured after the early 1970s^{[citation needed]}. During the 1960s, it was common that albums were released as both monaural LPs and stereo LPs, occasionally with slight differences between the two (again detailed information of The Beatles recordings provide a good example of the differences). This was because many people owned mono record players which were incapable of playing stereo records, as well as the prevalence of AM radio. Because of the limited quantities pressed and alternate mixes of several tracks, the monaural versions of these albums are often valued more highly than their stereo LP counterparts in record collecting circles today^{[citation needed]}.