An audio tape recorder, also known as a tape deck, tape player, tape machine, or simply a tape recorder, is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present-day form, it records a fluctuating signal by moving the tape across a tape head that polarizes the magnetic domains in the tape in proportion to the audio signal. Tape-recording devices include the reel-to-reel tape deck and the cassette deck, which uses a cassette for storage.
The use of magnetic tape for sound recording originated around 1930 in Germany as paper tape with oxide lacquered to it. Prior to the development of magnetic tape, magnetic wire recorders had successfully demonstrated the concept of magnetic recording, but they never offered audio quality comparable to the other recording and broadcast standards of the time. This German invention was the start of a long string of innovations that have led to present-day magnetic tape recordings.
Magnetic tape revolutionized both the radio broadcast and music recording industries. It gave artists and producers the power to record and re-record audio with minimal loss in quality as well as edit and rearrange recordings with ease. The alternative recording technologies of the era, transcription discs and wire recorders, could not provide anywhere near this level of quality and functionality.
Since some early refinements improved the fidelity of the reproduced sound, magnetic tape has been the highest quality analog recording medium available. As of the first decade of the 21st century, analog magnetic tape has been largely replaced by digital recording technologies.
History
Wax strip recorder The earliest known audio tape recorder was a non-magnetic, non-electric version invented by Alexander Graham Bell's Volta Laboratory and patented in 1886 (). It employed a strip of wax-covered paper that was coated by dipping it in a solution of beeswax and paraffin and then had one side scraped clean, with the other side allowed to harden. The machine was of sturdy wood and metal construction and hand-powered by means of a knob fastened to a flywheel. The wax strip passed from one eight-inch reel around the periphery of a pulley (with guide flanges) mounted above the V-pulleys on the main vertical shaft, where it came in contact with either its recording or playback stylus. The tape was then taken up on the other reel. The sharp recording stylus, actuated by a vibrating mica diaphragm, cut the wax from the strip. In playback mode, a dull, loosely mounted stylus, attached to a rubber diaphragm, carried the reproduced sounds through an ear tube to its listener. Both recording and playback styluses, mounted alternately on the same two posts, could be adjusted vertically so that several recordings could be cut on the same strip.
While the machine was never developed commercially, it somewhat resembled the modern magnetic tape recorder in its design. The tapes and machine created by Bell's associates, examined at one of the Smithsonian Institution's museums, became brittle, and the heavy paper reels warped. The machine's playback head was also missing. Otherwise, with some reconditioning, they could be placed into working condition.Newville, Leslie J. Development of the Phonograph at Alexander Graham Bell's Volta Laboratory, United States National Museum Bulletin, United States National Museum and the Museum of History and Technology, Washington, D.C., 1959, No. 218, Paper 5, pp.69–79. Retrieved from ProjectGutenberg.org.
The waxed tape recording medium was later refined by Edison's wax cylinder, and became the first widespread sound recording technology, used for both entertainment and office dictation. However, recordings on wax cylinders were unable to be easily duplicated, making them both costly and time consuming for large-scale production. Wax cylinders were also unable to record more than 2 minutes of audio, a problem solved by gramophone discs.
Celluloid strip recorder
Franklin C. Goodale adapted movie film for analog audio recording. He received a patent for his invention in 1909. The celluloid film was inscribed and played back with a stylus, in a manner similar to the wax cylinders of Edison's gramophone. The patent description states that the machine could store six records on the same strip of film, side by side, and it was possible to switch between them. In 1912, a similar process was used for the Hiller talking clock.
Photoelectric paper tape recorder In 1932, after six years of developmental work, including a patent application in 1931,USPTO. Official Gazette Of The United States Patent Office, United States Patent Office, 1936, Volume 463, pp.537.USPTO. United States Patent Office, Patent US2030973 A, "Method of and apparatus for electrically recording and reproducing sound or other vibrations" Merle Duston, a Detroit radio engineer, created a tape recorder capable of recording both sounds and voice that used a low-cost chemically treated paper tape. During the recording process, the tape moved through a pair of electrodes, which immediately imprinted the modulated sound signals as visible black stripes into the paper tape's surface. The audio signal could be immediately replayed from the same recorder unit, which also contained photoelectric sensors, somewhat similar to the various sound-on-film technologies of the era.Popular Science. Record Of Voice Now Made On Moving Paper Tape, Popular Science, Bonnier Corporation, February 1934, pp.40, Vol. 124, No. 2, ISSN 0161-7370.Onosko, Tim. Wasn't The Future Wonderful?: A View Of Trends And Technology From The 1930s: (article) Book Reads Itself Aloud: After 500 Years, Books Are Given Voice, Dutton, 1979, pp.73, , . Article attributed to: Popular Mechanics, date of publication unstated, likely c. February 1934.
Magnetic recording Magnetic recording was conceived as early as 1878 by the American engineer Oberlin SmithEngel, Friedrich Karl, ed. (2006) "Oberlin Smith and the invention of magnetic sound recording: An appreciation on the 150th anniversary of the inventor's birth". Smith's caveat of 4 October 1878 regarding the recording of sound on magnetic media appears on pp. 14–16. Available at: RichardHess.com Smith, Oberlin (1888 September 8) "Some possible forms of phonograph," The Electrical World, 12 (10) : 116–117. and demonstrated in practice in 1898 by Danish engineer Valdemar Poulsen. Analog magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization similar to the signal. A playback head can then pick up the changes in magnetic field from the tape and convert it into an electrical signal to be amplified and played back through a loudspeaker.
Wire recorders
The first wire recorder was the Telegraphone, invented by Valdemar Poulsen in the late 1890s. Wire recorders for law and office dictation and telephone recording were made almost continuously by various companies (mainly the American Telegraphone Company) through the 1920s and 1930s. These devices were mostly sold as consumer technologies after World War II.
Widespread use of wire recording occurred within the decades spanning from 1940 until 1960, following the development of inexpensive designs licensed internationally by the Brush Development Company of Cleveland, Ohio and the Armour Research Foundation of the Armour Institute of Technology (later Illinois Institute of Technology). These two organizations licensed dozens of manufacturers in the U.S., Japan, and Europe. Wire was also used as a recording medium in black box voice recorders for aviation in the 1950s.
Consumer wire recorders were marketed for home entertainment or as an inexpensive substitute for commercial office dictation recorders, but the development of consumer magnetic tape recorders starting in 1946, with the BK 401 Soundmirror, using paper-based tape, gradually drove wire recorders from the market, being "pretty much out of the picture" by 1952.Mooney, Mark Jr. "The History of Magnetic Recording." Hi-Fi Tape Recording 5:3 (February 1958), 37. This detailed, illustrated 17-page article is a fundamental source for early history of magnetic (wire/tape) recording: https://worldradiohistory.com/Archive-All-Audio/Archive-Tape-Recording/50s/Tape-Recording-1958-02.pdf
Early steel tape recorders
In 1924 a German engineer, Kurt Stille, developed the Poulsen wire recorder as a dictating machine. The following year a fellow German, Louis Blattner, working in Britain, licensed Stille's device and started work on a machine which would instead record on a magnetic steel tape, which he called the Blattnerphone. The tape was 6 mm wide and 0.08 mm thick, traveling at 5 feet per second; the recording time was 20 minutes.
The BBC installed a Blattnerphone at Avenue House in September 1930 for tests, and used it to record King George V's speech at the opening of the India Round Table Conference on 12 November 1930. Though not considered suitable for music, the machine continued in use and was moved to Broadcasting House in March 1932, a second machine also being installed. In September 1932, a new model was installed, using 3 mm tape with a recording time of 32 minutes.Video Recording Technology: Its Impact on Media and Home Entertainment, Aaron Foisi Nmungwun – Google Books pub. Routledge, Nov. 2012. The BBC Year-Book 1932 p.101, British Broadcasting Corporation, London W.1, retrieved 30 September 2015
In 1933, the Marconi Company purchased the rights to the Blattnerphone, and newly developed Marconi-Stille recorders were installed in the BBC's Maida Vale Studios in March 1935. The quality and reliability were slightly improved, though it still tended to be obvious that one was listening to a recording. A reservoir system containing a loop of tape helped to stabilize the speed. The tape was 3 mm wide and traveled at 1.5 meters/second.
They were not easy to handle. The reels were heavy and expensive and the steel tape has been described as being like a traveling razor blade. The tape was liable to snap, particularly at joints, which at 1.5 meters/second could rapidly cover the floor with loops of the sharp-edged tape. Rewinding was done at twice the speed of the recording.
Despite these drawbacks, the ability to make replayable recordings proved useful, and even with subsequent methods coming into use (direct-cut discs and Philips-Miller optical film), the Marconi-Stilles remained in use until the late 1940s.Information in this section from 'BBC Engineering 1922-1972' by Edward Pawley, pp178-182; plus some from colleagues who worked in BH in the 1930s.
Modern tape recorders
Magnetic tape recording as we know it today was developed in Germany during the 1930s at BASF (then part of the chemical giant IG Farben) and AEG in cooperation with the state radio RRG. This was based on Fritz Pfleumer's 1928 invention of paper tape with oxide powder lacquered onto it. The first practical tape recorder from AEG was the Magnetophon K1, demonstrated in Berlin, Germany in 1935. of AEG built the recorders and developed a ring-shaped recording and playback head. It replaced the needle-shaped head, which tended to shred the tape. Friedrich Matthias of IG Farben/BASF developed the recording tape, including the oxide, the binder, and the backing material. Walter Weber, working for at the RRG, discovered the AC biasing technique, which radically improved sound quality.