Monaural

Last updated
A diagram of monaural sound 1 0 channels (mono) label.svg
A diagram of monaural sound

Monaural or monophonic sound reproduction (often shortened to mono) is sound intended to be heard as if it were emanating from one position. This contrasts with stereophonic sound or stereo, which uses two separate audio channels to reproduce sound from two microphones on the right and left side, which is reproduced with two separate loudspeakers to give a sense of the direction of sound sources. In mono, only one loudspeaker is necessary, but, when played through multiple loudspeakers or headphones, identical signals are fed to each speaker, resulting in the perception of one-channel sound "imaging" in one sonic space between the speakers (provided that the speakers are set up in a proper symmetrical critical-listening placement). Monaural recordings, like stereo ones, typically use multiple microphones fed into multiple channels on a recording console, but each channel is "panned" to the center. In the final stage, the various center-panned signal paths are usually mixed down to two identical tracks, which, because they are identical, are perceived upon playback as representing a single unified signal at a single place in the soundstage. In some cases, multitrack sources are mixed to a one-track tape, thus becoming one signal. In the mastering stage, particularly in the days of mono records, the one- or two-track mono master tape was then transferred to a one-track lathe intended to be used in the pressing of a monophonic record. Today, however, monaural recordings are usually mastered to be played on stereo and multi-track formats, yet retain their center-panned mono soundstage characteristics.

Contents

Monaural sound has largely been replaced by stereo sound in most entertainment applications, but remains the standard for radiotelephone communications, telephone networks, and audio induction loops for use with hearing aids. FM radio stations broadcast in stereo, while most AM radio stations broadcast in mono. (Although an AM stereo broadcast standard exists, few AM stations are equipped to use it.) A few FM stations—notably talk-radio stations—choose to broadcast in monaural because of the slight advantage in signal strength and bandwidth the standard affords over a stereophonic signal of the same power.

History

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

Monaural sound is normal on:

Incompatible standards exist for:

Compatible monaural and stereophonic standards exist for:

No native monaural standards exist for:

In those formats, the mono-source material is presented as two identical channels, thus being technically stereo.

At various times artists have preferred to work in mono, either in recognition of the technical limitations of the equipment of the era or because of simple preference (this can be seen as analogous to filmmakers working in black and white). An example is John Mellencamp's 2010 album No Better Than This , recorded in mono to emulate mid-20th century blues and folk records. Some early recordings such as The Beatles' first four albums ( Please Please Me , With the Beatles , A Hard Day's Night , Beatles for Sale ) were re-released in the CD era as monophonic in recognition of the fact that the source tapes for the earliest recordings were two-track, with vocals on one track and instruments on the other (even though this was only true on the first two albums, while the latter two had been recorded on four-track). This was actually intended to provide flexibility in producing a final mono mix, not to provide a stereo recording, although because of demand this was done anyway, and the early material was available on vinyl in both mono and stereo formats. In the 1960s and 1970s, it was common in the pop world for stereophonic versions of mono tracks to be generated electronically using filtering techniques to attempt to pick out various instruments and vocals; but these were often considered unsatisfactory, owing to the artifacts of the conversion process.[ citation needed ]

Directors Stanley Kubrick and Woody Allen, among others, preferred to record their films' sound tracks in mono.

Monaural LP records were eventually phased out and no longer manufactured after the early 1970s, with a few exceptions. For example, Decca UK had a few double issues until the end of 1970 – the last one being Tom Jones's "I Who Have Nothing"; in Brazil records were released in both mono and stereo as late as 1972.[ citation needed ] During the 1960s it was common for albums to be released as both mono and stereo LPs, occasionally with slight differences between the two (again, detailed information of The Beatles' recordings provides a good example of the differences). This was because many people owned mono record players that were incapable of playing stereo records, as well as the prevalence of AM radio. Because of the limited quantities pressed and alternative 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 ]

On 9 September 2009, The Beatles re-released a remastered box set of their mono output spanning the Please Please Me album to The Beatles (commonly called "The White Album"). The set, simply called The Beatles in Mono , also includes a two-disc summary of the mono singles, B-sides and EP tracks released throughout their career. Also included were five tracks originally mixed for an unissued mono Yellow Submarine EP. Bob Dylan followed suit on 19 October 2010 with The Original Mono Recordings , a box set featuring the mono releases from Bob Dylan (1962) to John Wesley Harding (1967). On 21 November 2011, The Kinks' mono recordings were issued as The Kinks in Mono box set, featuring the releases of the band's albums from Kinks (1964) to Arthur (1969), with three additional CDs of non-album tracks that appeared as singles or EP tracks. When the initial run of the box set sold out, no more were pressed, unlike the Beatles and Dylan sets.

Compatibility between mono and stereo sound

Sometimes mono sound or monaural can simply refer to a merged pair of stereo channels - also known as "collapsed stereo" or "folded-down stereo". Over time some devices have used mono sound amplification circuitry with two or more speakers since it can cut the cost of the hardware. Some consumer electronics with stereo RCA outputs have a microswitch in the red RCA output (i.e., the right stereo channel) that disables merging of stereo sound into the white (left stereo channel) RCA output. Common devices with this are VCRs, DVD/Blu-ray players, information appliances, set-top boxes, and the like. Video game consoles sometimes have male RCA ends of cables with a proprietary multi-A/V plug on the other end, which prevents automatic stereo merging unless adapters are used.

Disadvantages of merged stereo involve phase cancellations that may have the effect of muffling the final sound output. If channels are merged after being sent through a power amplifier but before being connected to a loudspeaker, it places more stress on the loudspeaker. It has usually been the practice in recording studios to make separate mixes for mono recordings (rather than folded-down stereo-to-mono), so that the final mono master will avoid the pitfalls of collapsed stereo. In video games, merging stereo to mono sound prevents player from discerning what direction distant SFX are coming from, and reverse stereo has a similar setback too. Having an array of loudspeakers connected to their own amplifier outputs can mitigate issues with the electrical load for a single loudspeaker coil and allow the listener to perceive an "image" of sound in the free space between the speakers.

Mirrored mono

Mirrored mono sound is the opposite of merged stereo, since it can be a case where media with mono sound that stereo playback devices automatically mirror it with are played on both channels of the receiver. It can also mean having a mono input mixed down to stereo amplification circuitry, or a mono system with a headphone output compatible with stereo headphones. An example of an application where both merged stereo and mirror mono apply is when a compact audio cassette respectively plays back "summed" stereo channels on a mono reading head, and when a compact cassette recorded with mono sound is played back with a stereo tape head.

Other instances of "mirrored mono" also include using the right stereo channel in lieu of a "left" one (or vice versa) where both channels are wired to mirror only one.

Both

Instances of both "merged stereo" and "mirrored mono" can occur when the stereo channels are merged to a mono system with stereo headphone compatibility or when a mono system has "twin speakers" (or "pseudo-stereo").

Other applications that involve mirrored mono with merged stereo occur when MONO is available as an internal feature of a device that can toggle between STEREO and MONO, for instance many FM radios are capable of toggling between MONO and STEREO in a way where stereo can both MERGE into mono, and then MIRROR between both stereo speakers. This tactic can also be used on other devices, of which computer software and some video games will have a feature that will allow STEREO or MONO for the soundtrack, in which sometimes this can facilitate MERGING stereo internally to spare one from using a Y adapter with LEFT and RIGHT RCA plugs when using mono equipment, such as guitar amplifiers.

Native stereo equipment with mono-only features

Some TV/VCR combo decks on the market had stereo TV functionality with "twin speakers", whereas the VCR feature was only mono, which is typical of "consumer-grade VCRs" from decades ago. Some of these devices even had front RCA inputs for composite video (yellow), and mono audio (white) in which many of these devices didn't even have a right-channel RCA plug (red) even if it was just for "merging" stereo into mono for mono soundtracks to be recorded onto videotapes. This is odd since one would think that a "right channel" would be included for A/V in on a TV which had MTS stereo TV sound on its tuner.

Some stereo receivers will also include mono microphone inputs.

See also

Related Research Articles

RF modulator Electronic device

An RF modulator is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source.

RCA connector Electrical connector used for analog audio and video

RCA connector is a type of electrical connector commonly used to carry audio and video signals. The name RCA derives from the company Radio Corporation of America, which introduced the design in the 1930s. The connectors male plug and female jack are called RCA plug and RCA jack.

Mixing console Device used for audio mixing for recording or performance

In sound recording and reproduction, and sound reinforcement systems, a mixing console is an electronic device for combining sounds of many different audio signals. Inputs to the console include microphones being used by singers and for picking up acoustic instruments, signals from electric or electronic instruments, or recorded music. Depending on the type, a mixer is able to control analog or digital signals. The modified signals are summed to produce the combined output signals, which can then be broadcast, amplified through a sound reinforcement system or recorded.

Quadraphonic sound

Quadraphonic sound – equivalent to what is now called 4.0 surround sound – uses four audio channels in which speakers are positioned at the four corners of a listening space. The system allows for the reproduction of sound signals that are independent of one another.

Surround sound

Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener. Its first application was in movie theaters. Prior to surround sound, theater sound systems commonly had three "screen channels" of sound that played from three loudspeakers located in front of the audience. Surround sound adds one or more channels from loudspeakers to the side or behind the listener that are able to create the sensation of sound coming from any horizontal direction around the listener.

Phone connector (audio) Family of connector typically used for analog signals

A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog audio signals. The standard is that a plug will connect with a jack.

DIN connector

A DIN connector is an electrical connector that was originally standardized in the early 1970s by the Deutsches Institut für Normung (DIN), the German national standards organization. There are DIN standards for various different connectors, therefore the term "DIN connector" alone does not unambiguously identify any particular type of connector unless the document number of the relevant DIN standard is added. Some DIN connector standards are:

Near Instantaneous Companded Audio Multiplex (NICAM) is an early form of lossy compression for digital audio. It was originally developed in the early 1970s for point-to-point links within broadcasting networks. In the 1980s, broadcasters began to use NICAM compression for transmissions of stereo TV sound to the public.

Stereophonic sound Method of sound reproduction

Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term "stereophonic" applies to so-called "quadraphonic" and "surround-sound" systems as well as the more common two-channel, two-speaker systems. It is often contrasted with monophonic, or "mono" sound, where audio is heard as coming from one position, often ahead in the sound field. Stereo sound has been in common use since the 1970s in entertainment systems such as broadcast radio, TV, recorded music, internet, computer audio, and cinema.

Sound recording and reproduction recording of sound and playing it back

Sound recording and reproduction is an electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording.

Duophonic sound was a trade name for a type of audio signal processing used by Capitol Records on certain releases and re-releases of mono recordings issued during the 1960s and 1970s. In this process monaural recordings were reprocessed into a type of artificial stereo. Generically, the sound is commonly known as fake stereo or mock stereo.

Panning is the distribution of a sound signal into a new stereo or multi-channel sound field determined by a pan control setting. A typical physical recording console has a pan control for each incoming source channel. A pan control or pan pot is an analog control with a position indicator which can range continuously from the 7 o'clock when fully left to the 5 o'clock position fully right. Audio mixing software replaces pan pots with on-screen virtual knobs or sliders which function like their physical counterparts.

Haeco-CSG

The Haeco-CSG or Holzer Audio Engineering-Compatible Stereo Generator system was an analog electronic device developed by Howard Holzer, Chief Engineer at A&M Records in Hollywood, California.

History of multitrack recording

Multitrack recording of sound is the process in which sound and other electro-acoustic signals are captured on a recording medium such as magnetic tape, which is divided into two or more audio tracks that run parallel with each other. Because they are carried on the same medium, the tracks stay in perfect synchronisation, while allowing multiple sound sources to be recorded asynchronously. The first system for creating stereophonic sound was demonstrated by Clément Ader in Paris in 1881. The pallophotophone, invented by Charles A. Hoxie and first demonstrated in 1922, recorded optically on 35 mm film, and some versions used a format of as many as twelve tracks in parallel on each strip. The tracks were recorded one at a time in separate passes and were not intended for later mixdown or stereophony; as with later half-track and quarter-track monophonic tape recording, the multiple tracks simply multiplied the maximum recording time possible, greatly reducing cost and bulk. British EMI engineer Alan Blumlein patented systems for recording stereophonic sound and surround sound on disc and film in 1933. The history of modern multitrack audio recording using magnetic tape began in 1943 with the invention of stereo tape recording, which divided the recording head into two tracks.

An audio signal is a representation of sound, typically using either a level of electrical voltage for analog signals, or a series of binary numbers for digital signals. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz, which corresponds to the lower and upper limits of human hearing. Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, musical instrument pickup, phonograph cartridge, or tape head. Loudspeakers or headphones convert an electrical audio signal back into sound.

Dimensia was RCA's brand name for their high-end models of television systems and their components produced from 1984 to 1989, with variations continuing into the early 1990s, superseded by the ProScan model line. After RCA was acquired by General Electric in 1986, GE sold the RCA consumer electronics line to Thomson SA which continued the Dimensia line. They are significant for their wide array of advanced features and for being the first television receiver systems to feature a built in computer, somewhat of an early incarnation of a smart TV, but without internet access. In 1985, RCA released the Digital Command Component System, a fully integrated audio system that permitted the full functionality of Dimensia audio components without a Dimensia monitor. The name "Dimensia" actually dates back to the early 1970s when RCA used the term for an enhanced spatial stereo effect which they called "Dimensia IV". The tagline for the Dimensia was The Next Dimension in Sight and Sound.

Audio mixing (recorded music)

In sound recording and reproduction, audio mixing is the process of optimizing and combining multitrack recordings into a final mono, stereo or surround sound product. In the process of combining the separate tracks, their relative levels are adjusted and balanced and various processes such as equalization and compression are commonly applied to individual tracks, groups of tracks, and the overall mix. In stereo and surround sound mixing, the placement of the tracks within the stereo field are adjusted and balanced. Audio mixing techniques and approaches vary widely and have a significant influence on the final product.

<i>The Beatles in Mono</i> 2009 box set by the Beatles

The Beatles in Mono is a boxed set compilation comprising the remastered monaural recordings by the Beatles. The set was released on compact disc on 9 September 2009, the same day the remastered stereo recordings and companion The Beatles were also released, along with The Beatles: Rock Band video game. The remastering project for both mono and stereo versions was led by EMI senior studio engineers Allan Rouse and Guy Massey. The release date of 09/09/09 is related to the significance to John Lennon of the number nine.

Matrix mixer

A matrix mixer is an audio electronics device that routes multiple input audio signals to multiple outputs. It usually employs level controls such as potentiometers to determine how much of each input is going to each output, and it can incorporate simple on/off assignment buttons. The number of individual controls is at least the number of inputs multiplied by the number of outputs.

Music technology (electric) Musical instruments and recording devices that use electrical circuits

Electric music technology refers to musical instruments and recording devices that use electrical circuits, which are often combined with mechanical technologies. Examples of electric musical instruments include the electro-mechanical electric piano, the electric guitar, the electro-mechanical Hammond organ and the electric bass. All of these electric instruments do not produce a sound that is audible by the performer or audience in a performance setting unless they are connected to instrument amplifiers and loudspeaker cabinets, which made them sound loud enough for performers and the audience to hear. Amplifiers and loudspeakers are separate from the instrument in the case of the electric guitar, electric bass and some electric organs and most electric pianos. Some electric organs and electric pianos include the amplifier and speaker cabinet within the main housing for the instrument.