Contrary to popular belief, the influence of electricity and its associated hardware on the audio industry does not stem from the development of electronics following the invention of the valve or vacuum tube. Electromechanical systems were used from an early date as sound generators and audio transmission via purely “passive” electrical systems was in existence contemporary with Edison’s invention of the phonograph. Perhaps the most dramatic example of this was the transmission of performances from the Paris Opera House by Clement Ader in 1881. As part of that year’s Paris Exhibition of Electricity, Ader placed a series of specially constructed microphones across the front of the stage and connected them to remote receivers using telephone lines. By routing separate microphones to separate receivers, Ader (probably unintentionally) transmitted the first example of stereo sound.

Electricity or, more precisely, electronics offered a number of opportunities to the recording industry. Prior to its advent, the modulation of the groove of either a disk or cylinder recording bore, of necessity, a pretty direct relationship to the volume of the sound input to the recording horn. Electronics offered the ability to amplify quiet sounds and to attenuate loud ones and thus provided a significant opportunity to maximise modulation levels and hence optimise the volume of a recording, allowing it to acquire an enhanced ratio of desirable signal to undesirable noise.

The successive inventions, of the diode (Fleming, 1905) and the triode (deForest, 1906) vacuum tubes (valves) created the basis of electronic technology. In an odd parallel to the compressed air phonograph amplifier of Charles Short, the electronic amplifier created by de Forests’ technology used the relatively small current generated by a microphone (at this time usually little more than a telephone mouthpiece) to modulate a much larger current derived from the mains electricity supply. This in turn could drive a loudspeaker or, more significantly, a disk-cutting head. This latter was essentially a modified loudspeaker wherein an electric current caused a cutting stylus (rather than a paper cone) to vibrate in much the same way as the movement of a traditional cutting stylus was acoustically induced by the vibration of the recording membrane. The immediate advantage of the electrical cutting system was that the signal could, by relatively simple means, be optimised and hence the recording could be cut at the highest possible amplitude.

Like many rock bands of the 60s and 70s, to be as loud as possible had long been an objective of acoustic recording. In pursuit of this objective, inventors had resorted to increasingly eccentric principles (including the modulation of a gas flame, hand pumps, gravity drives, hydraulics, hot air engines and cylinders of compressed gas) in their attempts to create the highest possible volume of both cut and playback output. Another well-intentioned anachronism may be identified in the parallel between the contemporary 45rpm, 10 inch “dance mix” and the wide-pitch disks cut by Starkton and Gaydon for use on the 1910 “Stentorphone” (lit. “loud sound”). In both instances, the objective was to maximise volume by increasing cutting modulation. A further parallel may be found in the Pathe Orthophone of 1909 which utilised 20 inch disks running at 120 rpm with the intention of increasing both bandwidth and volume. Truly, these were the stadium technologies of their time but, except where electricity was unavailable, they were unable to compete with the power and flexibility offered by electronics. Developing logically from the electric light bulb (another Edison invention), the valve and the technology of electronics which it spawned was to have perhaps the greatest single influence ever on audio technology

The first records to be electrically cut appeared in 1925, based on a system developed by Bell Laboratories. Despite continuing technical limitations, they represented a substantial improvement in audio quality and, since the microphone (or, more significantly, microphones) had replaced the horn as the recording instrument, it was now possible to record full size orchestras for the first time while maintaining a degree of instrumental or sectional balance.

The microphone at this stage of its development was a relatively crude device, little different to the telephone mouthpiece from which it had evolved. As such it possessed limited sensitivity and a greatly restricted frequency response. For as long as record reproduction was achieved acoustically, these factors were of little consequence but, with the advent of radio broadcasting with its inherently higher potential sound quality, it became necessary to extract higher performance from microphones. Two main types of microphone evolved in response: the dynamic and the condenser.

Dynamic microphones, invented in 1878, used the electrical principle of a dynamo whereby a movable conductive element vibrated in response to incoming sound. This vibration took place in close proximity to a strong permanent magnet thus inducing a small current in the moving element, usually a fine coil attached to a diaphragm or, more commonly in early units, a very thin ribbon of metal foil which acted as both diaphragm and coil. Condenser microphones, developed in 1922 by Bell Laboratories, also borrowed an electrical principle from elsewhere by allowing a diaphragm to move in relation to another fixed one, both being electrically charged. As they moved in relation to each other, the capacitance of the system would vary correspondingly and this could readily be translated into a varying voltage (like that of other microphones) by means of simple valve circuitry. As a general principle, the condenser type gave higher sensitivity and a warmer sound, resulting in it being favoured by vocalists.

Other components too evolved rapidly: the reverse of a dynamic microphone became the loudspeaker, initially a low-power device using an acoustic horn to optimise its output but rapidly developing into a substantial and powerful system in its own right. Amplifiers proved electronically simple to construct and capable of substantial power output without serious detriment to audio quality. Likewise, radio transmitters and receivers evolved to considerable power on the one hand and remarkable sensitivity on the other. Radio quality, although substantially better than acoustic reproduction, was severely limited in bandwidth by virtue of the amplitude modulation transmission system that had been universally adopted. High fidelity radio had to wait for the advent of FM (frequency modulation) broadcasting in 1962, a process nearly 30 years in the making following its theoretical discovery in 1933 by Edwin Armstrong.

Hugo Fessenden undertook the first radio transmission of the human voice in 1906, but it was not until 1920, following the developments of wireless telegraphy forced by World War 1 that what would now be recognisable as a radio station was established. KDKA in Pittsburgh, USA began public broadcasting in 1920 - the first commercial radio station. The one-off low cost of receivers and the simplicity of radio proved irresistible to the mass market who, perceiving the financial advantage of “free” music as opposed to the ongoing cost of record buying, deserted the phonograph in droves. Programming was extremely limited and transmissions were sometimes erratic but, nonetheless, the sound quality and sheer affordableness of radio was such as to push the recording industry into a steep decline in the later 1920s.

A further influence was the advent in 1927 of the talking picture. The earliest acknowledged full sound movie was Al Jolsons’ “The Jazz Singer” but this actually used gramophone records mechanically synchronised to the image. Known as the “Vitaphone” system, this attempt was essentially disastrous from a practical standpoint being plagued by mechanical problems and the unfortunate habit of the disks to disintegrate without warning.

The film industry was responsible for a number of significant technical developments including the radio microphone (1917) and optical stereo recording (early 1920s). Early experiments with synchronised sound were made by Edison (who also invented the cinematograph) when he demonstrated his Kinetophone in 1895. Various attempts followed, more or less unsuccessfully until Lee de Forest demonstrated the first viable sound-on-film medium, Phonofilm, in 1923. It was a rival development by Western Electric that led to the creation of the initially dominant Vitaphone system which debuted in 1920 with a recorded speech by the then President of the United States followed in 1926 by the first sound film “Don Juan” which featured music and sound effects but not synchronised dialogue. This had to wait until the appearance of “The Jazz Singer” the following year.

Despite its technical problems, the talking picture clearly worked and had the potential to command a substantial audience in Depression-afflicted America where, for a relatively small sum, audiences could be transported to a world less wretched than that of their daily reality. Unfortunately, the equipment was specialised and not universally available.However, one innovation of that time did endure: film makers eager to use sound needed disks that played for longer than usual since a reel of film was 300m long and ran for 11 minutes. Because sound and picture were driven from a common source, it was a simple matter to adjust the gear ratios to make the disk part of the mechanism play slower and hence longer. The final speed of the record player turned out to be 33 1/3 rpm and this speed was soon adopted for transcription recordings and, later, the long playing record format.

With the financial backing of the film industry, it became feasible to undertake the research and development required to create the first true multiple media presentation system: the talking picture. While it was obviously possible to synchronise sound and picture by simple mechanical means, a level of potential instability and possible incompatibility inevitably existed for as long as the two components occupied and were delivered by separate media - the film and the disk.

The logical development was to create a system whereby they were both supported by one single medium and, since images could not readily be translated to disk, the logical assumption was made that sound might be translated to film. Thus it was that the soundtrack was created, based ultimately upon the 1905-1910 work of Eugene Lauste.

In its early form, a bulb was fed a varying electrical supply which represented an audio input: in other words, its intensity was modulated by the sound.As the bulb brightened or darkened, it would expose motion picture film to a degree which, when developed, would display a correspondingly variable optical density. To play the sound back, a bulb of fixed intensity had only to be focussed upon the film and the amount of light transmitted could then be “read” by a photoelectric cell which could translate the varying intensity back into an electrical signal reproducible by a conventional amplifier. Better still, it was discovered that, while a separate “sound camera” was initially required for recording purposes, the recorded track could be condensed down in size to a sufficient extent that it could appear as a stripe down the unused edge of the picture film. In due course, it proved possible to carry out audio recording in the picture camera effecting a considerable reduction in complexity and creating, for the first time,a sound and image based newsgathering technology.

Thus married, sound and image could be widely distributed by virtue of a simple, low-cost bolt-on attachment to a standard movie projector. Add an amplifier and loudspeaker and voila ! Unfortunately, the sound that was finally reproduced was of highly variable quality due to the vast range of enthusiastically cobbled together systems that emerged. If this new medium was to maintain public credibility, it was clearly necessary to establish a way of creating and maintaining some sort of standard to serve as a reference point. Two developments served this purpose: the light valve and the Academy Curve.

The light valve was once more a development from the early work of Lauste and improved upon the earlier variable density soundtrack by rendering the sound into a uniformly fully exposed image wherein the area varied in response to the audio input, creating a trace not unlike that of an oscilloscope.The total amount of light transmitted by the track on playback still varied in much the same way as that of the variable density track so there was no problem of hardware compatibility but the response and resolution was substantially enhanced. This system remains in use today for monophonic film sound.

The Academy Curve was (is) in fact a frequency response graph which required that the reproducing system have certain frequency-dependent characteristics. Provided the overall reproducing system response followed this curve, it was argued, the public would hear substantially the same sound wherever they chose to view a movie. Nonetheless, cinemas competed to offer the best sound systems and this provided much of the impetus behind the technological developments that were later to be incorporated into live sound systems for performance use. Companies set up to exploit this market included J B Lansing (later JBL) and Altec, both of whom became major players in the PA system market in later years, their success being based at least in part on having developed sound systems able to fill a large theatre with high quality sound - a capability at least as useful to a rock band as to a motion picture distributor. In a similar way, a subsequent generation of film-makers have also exploited standardised replay environments to their advantage in the form of the THX system in which individual theatres are tested and, if successful, awarded a certificate of suitability for the exhibition of films with soundtracks made to THX standards

Meanwhile, in 1934 came the invention of Muzak. Although now used as a pejorative term, Muzak was created as a service industry aimed at the domestic environment, supplying its patrons with music in return for a regular subscription. The creation of a former US Army general, George Squier, Muzak transmitted three channels of prerecorded music to homes in the Cleveland (USA) area for a monthly charge of $1.50. In another technological echo, a UK-based network has begun - in 2000 - to offer its subscribers the option of listening to selected music over their mobile phones.

By 1933, there was a desperate need to persuade the public to buy records once more. Unfortunately, the American public owned around 20,000,000 radios and showed little interest in making the extra investment in an electric record player. One solution (adopted by RCA) was to create a small record playing attachment that could be connected to a radio set. Called the Duo Junior, it was marketed in 1934 at a retail cost of $10.00 and almost singlehandedly revitalised flagging record sales.

Despite its residence in the economic doldrums, the record was progressing. In 1932, RCA had marketed long-playing records in an attempt to eradicate the nuisance of having classical works spread over numerous 12″ 78rpm disks (These sets of disks were originally sold in book-like multiple sleeves, the origin of the term “album”.) Made of vinyl, the sound quality of these recordings was generally agreed to be excellent but the tracking weight of pickups was such that the disks wore out at an unacceptably high rate leading to their withdrawal in 1933. For the time being, the “standard” shellac 78 reigned supreme.

Another particularly significant invention (dating originally from 1927) was the juke box, adopted by bars and cafes to provide both background music and additional income. Although slow to get off the ground, the abolition of Prohibition and the invention by Capehart of the automatic record changing mechanism in 1933 led quickly to widespread use with numbers of juke boxes in the USA rising from 25,000 in 1934 to 300,000 in 1939. At last, with the creation of its first mass market, the record industry emerged from its decline achieving annual sales of around 13 million disks a year by the end of the decade. This ability of patrons to select their choice of music and led directly to the creation of “The Charts” when a journalist noticed that certain records were played repeatedly by juke box patrons. The first radio chart show was “Hit Parade” which was initially broadcast in 1935, the same year as the emergence of the first DJ, Martin Block whose radio show “Make Believe Ballroom” earned $500,000 dollars in its first year.

Interest in development of the long playing record was rekindled in 1939 when Columbia Records established a policy of double recording: not only creating 78 rpm masters but also recording simultaneously at 33 rpm using huge 16 inch vinyl disks. Although not immediately intended for commercial release, the disks provided an instant high quality archive, ready for the introduction of the LP. In the interim, they were widely adopted for transcription use where repeated playing was unlikely and the excessive wear rate was therefore unimportant. Rival companies were forced to remaster from lower quality 78s, giving Columbia a significant technical and sales advantage that lasted for nearly 10 years. Unfortunately, World War 2 intervened and development work was suspended, the LP finally seeing the light of day until 1948. More dramatically, all “nonessential” recording was stoppedin the US in August 1942 due to a shortage of shellac and other raw materials.

Nonetheless, by the end of the war, the American record industry was in reasonable financial shape and the market was judged to be ready for the introduction of the LP. A number of technical problems still had to be overcome, however: cutting problems remained, necessitating the introduction of new methods using heated cutter heads and variable groove pitch (to accommodate extremes of modulation level), but most intractable of all was the issue of excessive wear on playback. This was finally resolved by the creation of the lightweight variable reluctance pickup in 1946. Over the next 2 years, the LP continued to improve in duration, going from 7 minutes per side in 1946 to 11 minutes in 1947 but it was not until late that year that it reached 17 minutes per side.This seemingly arbitrary figure was adopted as a target playing time since research had shown that it would allow up to 90% of the classical repertoire to be accommodated on the two sides of a single disk.

The LP was finally marketed in June 1948 with a capacity of 23 minutes per side.  In many ways, its creation was a landmark in the process of technological development. The required outcomes were now so complex that it was no longer feasible for an individual inventor to work alone with some reasonable hope of success: what was now required was the diverse resource base of a large and well funded industry. Peter Goldmark is the individual generally credited with the “invention” but, as a piece of corporate research which drew upon a range of disciplines, it was no longer really possible to attribute such developments to any one individual.

Meanwhile, Columbia’s main commercial rival, RCA had developed another product, the Extended Play record or EP. This was a 7 inch 45 rpm vinyl disk which had insufficient capacity for major classical works but which was quickly adopted for popular music. For some time, Columbia and RCA competed vigorously to win the format war, but it quickly became apparent that they were really suited to quite different markets and so were born the “single” and “album” formats that have remained in use until the upsurge of the compact disk in the 1980s.