From Steel Pins to MP3
A Brief History of Sound Recording and Reproduction
An eBook by Cyril J Wood
There have been many forms of mechanical sound reproduction in the years leading up to the development of Thomas Alva Edison's "Phonograph" in 1877. The earliest forms recorded are mechanical bell ringers developed in the 14th century. In these machines, the bells were controlled by a rotating cylinder that rang the bells via pegs on the cylinder. Similar designs appeared in the 15th century in the form of barrel organs and music boxes much later around 1815. These devices could play stored music on the musical instrument they were attached to but lacked the ability to record and reproduce natural sounds as heard at a live performance. The first device that could record actual sounds mechanically but the ability to replay recorded sounds was the Phonautograph, developed in 1857 by Edouard-Leon Scott. Initially, the phonautograph made recordings onto a lamp-blackened glass plate but a later version used a medium of lamp-blackened paper on a drum or cylinder. Another version would draw a line representing the sound wave on a roll of paper. The phonautograph was a laboratory instrument for the study of acoustics and was used to determine the frequency of a given musical pitch and to study the properties of sound and speech.
The player piano, first demonstrated in 1876, used a punched paper scroll that could store an arbitrarily long piece of music. This piano roll moved over a device known as the 'tracker bar', which first had 58 holes, was expanded to 65 and then was upgraded to 88 holes (generally, one for each piano key). When a perforation passed over the hole, the note sounded. Piano rolls were the first stored music medium that could be mass-produced, although the hardware to play them was much too expensive for personal use. Technology to record a live performance onto a piano roll was not developed until 1904. Piano rolls have been in continuous mass production since around 1898. The use of piano rolls began to decline in the 1920s although one type is still being made today. The fairground organ, developed in 1892, used a similar system of accordion-folded punched cardboard books.
The first attempt at true sound recording and reproduction is credited to Thomas Alva Edison with his invention of the "Phonograph". This instrument utilised a large horn as a crude form of microphone similar in concept to a megaphone. The sound waves from the subject to be recorded were "captured" by the horn and focused onto a metal diaphragm. The diaphragm was connected to a stylus that traced a groove onto a wax cylinder rotated by a clockwork motor that also moved the stylus carriage along a guide. As the stylus moved and the cylinder rotated, the groove spiralled across the outside face of the cylinder. The walls of the resulting groove carried an analogue representation of the sound waves and when the recording was played back, the undulations in the groove were again traced by the stylus which vibrated the diaphragm and the resulting sound waves amplified by the horn allowing them to be heard by the listener. Various sizes of cylinder were produced which increased the length of recording time available.
As time went by, the system was developed and one type of cylinder, the Lioret, used celluloid instead of wax to produce a more permanent recording. Some recordings were also made to add a synchronised soundtrack to a motion picture film as early as 1913. These developments were, however, overshadowed by Berliner's invention of the Gramophone Disc. Similar in concept to the Cylinder but made from a 10 inch Shellac (an early form of brittle plastic similar to Bakelite) disc rotating at 78 rpm and was a playback only format. The recordings were produced in a primitive recording studio were a special blank disc and a turntable known as a Cutting Lathe produced a "Master Disc" from which the Shellac discs or "records" were produced.
Early Electronic Reproduction
The invention of the "Thermionic Valve" in the 1920's opened up new possibilities for the reproduction of records, allowing a greater clarity of sound and more control over its reproduction. The diaphragm vibrated by the stylus was replaced by coils of fine electrical wire moving inside a magnetic field to produce the electrical signal amplified by the valves. Later developments used a pietzo crystal and moving magnets to increase the relatively low output of the moving coil pick-up. Electric motors were also introduced which eliminated the need to "wind up" the clockwork motor that powered the turntable and provided a more stable rotational speed producing less "wow" (low frequency speed deviation) although it did seem more prone to "flutter" (high frequency speed deviation).
The 10 inch, 78 rpm format remained popular until the late 1950's when a more compact 7 inch disc rotating at 45 rpm was introduced. From this was developed a "Long Play" 12 inch disc rotating at 33 rpm and an "Extended Play" disc with finer grooves rotating at the same speed. Limited edition 12 inch singles rotating at 45 rpm came next and proved very popular with disc jockeys in the "Discotheques" of the time. Even today, this format of disc is still in use.
Wire and Tape Recording
The next development came in 1978 with the introduction of a smaller 5 inch plastic disc rotating at 50 rpm and encoded with digital information to produce a near faultless representation of the original sound source. This was the developed by Philips in Germany. Two years later, Sony of Japan joined Philips to perfect a commercially viable format that was to become known as the "Compact Disc". It was launched in Japan in 1982 and eventually launched in Europe in 1983. The sound signal was represented as "pits" and "troughs" on a protected part of the disc and was "read" by a low powered laser. The resulting output from the laser was converted from a digital format into an analogue one capable of being fed into hi-fi amplifiers and hence, driving the loudspeakers. Such is the versatility of the CD as it has become known, it can be used to store not only audio programs but also video images, computer programs and files.
Initially, the CD was a read-only format but there is an increasing interest and popularity in recordable CD's. The information recorded can be in the form of computer files and programs or music. There are two types of recordable CD. "CDR" (CD Recordable), where a laser heats up the substrate layer on the blank disc to produce bubbles that can deflect the playback laser's beam in the same way that the troughs do on a pre-recorded disc. Once recorded, the disc can not be re-recorded or re-written. The second type of recordable CD is the "CDRW" (CD Re-Writable). The principle is similar to that of CDR but the substrate coating has a coloured dye that is changed in hue by the laser when writing. For re-recording, the dye layer is changed again to match the new recording.
Initially, CD recorders were only available as an addition to a home computer, but manufacturers are now producing "stand alone" units that are connected to a Hi-Fi system. CDR has a better archival permanence (approx. 100 years) compared to the CDRW (about 25 years). The CDR is better suited for recording files that are intended to be stored for a long time (such as image or computer files). This is due to the coloured dye in CDRW possibly being affected by prolonged exposure to light and extremes of temperature. Also, many CD players ar e not suitable for the playback of CDR and even fewer can accommodate CDRW.
Another modern development is the "DVD". This is very similar to the CD but, at present, is generally used for the storage of feature films. A conventional CD is capable of storing 650 Mb of information whereas the DVD can hold approximately 2.5 Gb (5 Gb if of dual layer construction) and more powerful information compression. The DVD is gradually gaining popularity and will eventually replace the VHS videotape format. Denon are already producing music DVD's and various manufacturers are recording computer programs in this format as an alternative to CD.
A form of recordable DVD has been available for a while in the guise of the "DVD RAM", a type of computer memory storage device capable of storing 5.2 GB. It could replace the conventional hard-drive in a computer if sufficiently developed. However, domestic recordable DVD's in the form of the "DVD RW" are looming on the horizon, and when released, may sound the death knell for the videocassette in the domestic environment.
The CD was not the first digital recording medium, as long ago as 1972 Denon produced the DN-023R reel to reel digital tape recorder for the professional market. Whilst on the subject of the reel to reel tape recorder, this format was initially produced as a wire recorder by Telefunken in Germany prior to the Second World War. The introduction of plastic coated with ferric oxide dust by BASF meant that recording times were increased and weight reduced as well as increasing the overall performance. Ultra high-speed recorders produced in the early 1960's by Ampex in the USA gave the tape format the ability to record television or video images. In the 1950's, Grundig popularised the reel to reel with its "TK" range of domestic machines until Philips introduced the "Compact Cassette" in 1966.
The Compact Cassette has remained popular in its original format up to the present day and with modern cobalt-doped ferric or metal coatings is capable of producing hi-quality sound. its popularity has been threatened on numerous occasions by formats such as the "Four Track" cartridge. Originally developed by Lear Jet in America for use in their executive jets, it gained popularity with car manufacturers who installed Four Track players as an optional extra. BASF's "Elcassette" was developed jointly with Sony, used quarter inch tape housed in a turnover cassette and was launched onto the market in 1974 but didn't last long. Sony's "DAT" (Digital Audio Tape) found a place in recording studios and Philips' rival to this was the "DCC" (Digital Compact Cassette), which was backwards compatible with the Compact Cassette but also died a natural death.
A late comer to the domestic recording medium was the Sony "Minidisk". Minidisk used a small CD type disc housed in a package similar to a computer floppy disc . its near-CD quality and ease of editing has made it reasonably popular but the advent of recordable CD's may see it destined for the obsolete drawer. None of these formats have approached the popularity of the Compact Cassette and have either fallen by the wayside or remain in the domain of the professional recorder.
Whilst totally different in concept, it is surprising just how many comparisons can be drawn between photographic and audio recording. For instance; a sound recording may be stored on recording tape at some stage of its life. The tape consists of a Mylar (Nylon) base material coated with an emulsion consisting of Ferric Oxide in one guise or another. The photographic image may be stored on film that consists of a similar base material but with a coating based on a different metal... Silver. After experimenting with digital recordings on both reel and cassette based packages, the technologies have converged with the integration of audio/visual recordings on DVD. Another parallel can be drawn between the recording of video and photographic images on Flash Memory and MP4 players with the recording of sound onto electronic memories within MP3 players.
The future of recording will most probably lie in digital holographic memories capable of storing high quality audio, video and photographic images simultaneously. This is due to their lack of moving parts which are prone to wearing out and "current hungry", but as to what that format will be is anybody's guess... so we will just have to wait and see (or hear).
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Wyre Heal - Wirral's Local History
Wheels and Props
Half Term Adventure
Footnote and About the Author
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