The history of sound recording, which has progressed in waves, driven by the invention and commercial introduction of new technologies, can be roughly divided into four main periods: The Acoustic era (1877–1925) The Electrical era (1925–1945) The Magnetic era (1945–1975) The Digital era (1975–present)
Experiments in capturing sound on a recording medium for preservation and reproduction began in earnest during the Industrial Revolution of the 1800s. Many pioneering attempts to record and reproduce sound were made during the latter half of the 19th century – notably Édouard-Léon Scott de Martinville's phonautograph of 1857 – and these efforts culminated in the invention of the phonograph by Thomas Edison in 1877.
Digital recording emerged in the late 20th century and has since flourished with the popularity of digital music and online streaming services.
Overview
Experiments Before True Playback (1857–1876) The first patented device for intentionally recording sound waveforms was called the "Phonoautograph" and patented in 1857. Nevertheless, the record it produced could not yet be played back out loud. (Modern researchers have discovered that some of these recordings do contain enough information for playable clips to be reconstructed; work between 2007 and 2009 recovered the attached "Au clair de la lune," 1860).
Alongside these early experiments, advances were also being made in the transmission of live audio. Alexander Graham Bell introduced a working telephone in 1876, which helped stimulate the research of Thomas Edison that would produce playable recordings the following year.
The Acoustic Era (1877–1925)
Edison's phonograph introduced true sound recording capable of playback in 1877. The earliest practical recording technologies were entirely mechanical devices. These recorders typically used a large conical horn to collect and focus the physical air pressure of the sound waves produced by the human voice or musical instruments. A sensitive membrane or diaphragm, located at the apex of the cone, was connected to an articulated scriber or stylus, and as the changing air pressure moved the diaphragm back and forth, the stylus scratched or incised an analog of the sound waves onto a moving recording medium, such as a roll of coated paper, or a cylinder or disc coated with a soft material such as wax or a soft metal.
These early recordings were necessarily of low fidelity and volume and captured only a narrow segment of the audible sound spectrum — typically only from around 250 Hz up to about 2,500 Hz—so musicians and engineers were forced to adapt to these sonic limitations. Musical ensembles of the period often favored louder instruments such as trumpet, cornet, and trombone; lower-register brass instruments such as the tuba and the euphonium doubled or replaced the double bass, and blocks of wood stood in for bass drums. Performers also had to arrange themselves strategically around the horn to balance the sound and to play as loudly as possible. The reproduction of domestic phonographs was similarly limited in both frequency range and volume.
By the end of the acoustic era, the disc had become the standard medium for sound recording, and its dominance in the domestic audio market lasted until the end of the 20th century.
The Electrical Era (1925–1945) (including sound on film)
The second wave of sound recording history was ushered in by the introduction of Western Electric's integrated system of electrical microphones, electronic signal amplifiers and electromechanical recorders, which was adopted by major US record labels in 1925. Sound recording now became a hybrid process — sound could now be captured, amplified, filtered, and balanced electronically, and the disc-cutting head was now electrically powered, but the actual recording process remained essentially mechanical – the signal was still physically inscribed into a wax master disc, and consumer discs were mass-produced mechanically by stamping a metal electroform made from the wax master into a suitable substance, originally a shellac-based compound and later polyvinyl plastic.
The Western Electric system greatly improved the fidelity of sound recording, increasing the reproducible frequency range to a much wider band (between 60 Hz and 6000 Hz) and allowing a new class of professional – the audio engineer – to capture a fuller, richer, and more detailed and balanced sound on record, using multiple microphones connected to multi-channel electronic amplifiers, compressors, filters and mixers. Electrical microphones led to a dramatic change in the performance style of singers, ushering in the age of the crooner, while electronic amplification had a wide-ranging impact in many areas, enabling the development of broadcast radio, public address systems, and electronically amplified home record players.
In addition, the development of electronic amplifiers for musical instruments now enabled quieter instruments such as the guitar and the string bass to compete on equal terms with the naturally louder wind and horn instruments, and musicians and composers also began to experiment with entirely new electronic musical instruments such as the Theremin, the Ondes Martenot, the electronic organ, and the Hammond Novachord, the world's first analog polyphonic synthesizer.
Contemporaneous with these developments, several inventors were engaged in a race to develop practical methods of providing synchronised sound with films. Some early sound films — such as the landmark 1927 film The Jazz Singer – used large soundtrack records which were played on a turntable mechanically interlocked with the projector. By the early 1930s, the movie industry had almost universally adopted sound-on-film technology, in which the audio signal to be recorded was used to modulate a light source that was imaged onto the moving film through a narrow slit, allowing it to be photographed as variations in the density or width of a soundtrack running along a dedicated area of the film. The projector used a steady light and a photoelectric cell to convert the variations back into an electrical signal, which was amplified and sent to loudspeakers behind the screen.
The adoption of sound-on-film also helped movie-industry audio engineers to make rapid advances in the process we now know as multi-tracking, by which multiple separately recorded audio sources (such as voices, sound effects and background music) can be replayed simultaneously, mixed together, and synchronized with the action on film to create new blended audio tracks of complexity. One of the best-known examples of a constructed composite sound from that era is the famous "Tarzan yell" created for the series of Tarzan movies starring Johnny Weissmuller.
Among the vast and often rapid changes that have taken place over the last century of audio recording, it is notable that there is one crucial audio device, invented at the start of the Electrical Era, which has survived virtually unchanged since its introduction in the 1920s: the electro-acoustic transducer, or loudspeaker. The most common form is the dynamic loudspeaker – effectively a dynamic microphone in reverse. This device typically consists of a shallow conical diaphragm, usually of a stiff paper-like material concentrically pleated to make it more flexible, firmly fastened at its perimeter, with the coil of a moving-coil electromagnetic driver attached around its apex. When an audio signal from a recording, a microphone, or an electrified instrument is fed through an amplifier to the loudspeaker, the varying electromagnetic field created in the coil causes it and the attached cone to move backwards and forward, and this movement generates the audio-frequency pressure waves that travel through the air to our ears, which hear them as sound.
Although there have been numerous refinements to the technology, and other related technologies have been introduced (e.g., the electrostatic loudspeaker), the basic design and function of the dynamic loudspeaker has not changed substantially in 90 years, and it remains overwhelmingly the most common, sonically accurate and reliable means of converting electronic audio signals back into audible sound.
The Magnetic Era (1945–1975)
The third wave of development in audio recording began in 1945 when the Allied nations gained access to a new German invention: magnetic tape recording. The technology was invented in the 1930s but remained restricted to Germany (where it was widely used in broadcasting) until the end of World War II. Magnetic tape provided another dramatic leap in audio fidelity—indeed, Allied observers first became aware of the existence of the new technology because they noticed that the audio quality of obviously pre-recorded programs was practically indistinguishable from live broadcasts.
On a controversial 1936 tour of Germany, the London Philharmonic Orchestra inadvertently made the first recognised full sound recording on magnetic tape on November 19, 1936, at the BASF Feierabendhaus (the company auditorium), but the sound was not as good as wax transcription discs, due to DC bias. The orchestra played Symphony No. 39 (Mozart) and Delius's On Hearing the First Cuckoo in Spring.
After a renovation of the BASF building in 2011, the orchestra performed at the reopening, in Germany, on November 27, 2011, with Vladimir Jurowski. It was 75 years after that first recording.
From 1950 onwards, magnetic tape quickly became the standard medium of audio master recording in the radio and music industries and led to the development of the first hi-fi stereo recordings for the domestic market, the development of multi-track tape recording for music, and the demise of the disc as the primary mastering medium for sound. Magnetic tape also brought about a radical reshaping of the recording process—it made possible recordings of far longer duration and much higher fidelity than ever before, and it offered recording engineers the same exceptional plasticity that film gave to cinema editors—sounds captured on tape could now easily be manipulated sonically, edited, and combined in ways that were simply impossible with disc recordings.
These experiments reached an early peak in the 1950s with the recordings of Les Paul and Mary Ford, who pioneered the use of tape editing and multi-tracking to create large virtual ensembles of voices and instruments, constructed entirely from multiple taped recordings of their own voices and instruments. Magnetic tape fueled a rapid and radical expansion in the sophistication of popular music and other genres, allowing composers, producers, engineers and performers to realize previously unattainable levels of complexity. Other concurrent advances in audio technology led to the introduction of a range of new consumer audio formats and devices, on both disc and tape, including the development full-frequency-range disc reproduction, the change from shellac to polyvinyl plastic for disc manufacture, the invention of the 33 rpm, long-playing (LP) disc and the 45 rpm single, the introduction of domestic and professional portable tape recorders (which enabled high-fidelity recordings of live performances), the popular 4-track cartridge and compact cassette formats, and even the world's first sampling keyboards, the pioneering tape-based keyboard instrument the Chamberlin, and its more famous successor, the Mellotron.
The Digital Era (1975–present)