Image:Reel-to-reel recorder tc-630.jpg An audio tape recorder tape deck [[Reel-to-reel audio tape recording|reel-to-reel tape deck]] [[cassette deck]] or tape machine is an Sound recording and reproduction device that records and plays back sounds, including articulated voices, usually using magnetic tape either wound on a reel or in a Compact Cassette for storage. It its present day form, it records a fluctuating signal processing by moving the tape across a tape head that polarizes the magnetic domains in the tape in proportion to the audio signal.

History

File:Early experimental non-magnetic Tape Recorder invented by the Volta Associates -Bell & Tainter -i013.jpg

Earliest variant: non-magnetic wax strip recorder

Likely the earliest known audio tape recorder was a Magnetism electricity version invented by Alexander Graham Bell s Volta Laboratory and Bureau 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 the 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 reproducing heads, 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 was an interesting ancestor to the modern magnetic tape recorder which it resembled somewhat in design. The tapes and machine created by Bells associates, examined at one of the Smithsonian Institution s museums, became brittle, and the heavy paper reels warped. The machines playback head was also missing. Otherwise, with some reconditioning, they could be placed into working condition.Newville, Leslie J. http://www.gutenberg.org/files/30112/30112-h/30112-h.htm Development of the Phonograph at Alexander Graham Bells Volta Laboratory], United States National Museum Bulletin, Smithsonian Institution and the Museum of History and Technology Washington, D.C., 1959, No. 218, Paper 5, pp.69-79. Retrieved from ProjectGutenberg.org.

Photoelectric variant

In 1932, after six years of developmental work, Merle Duston, a Detroit radio engineer created a tape recorder that used a low-cost chemically-treated paper tape, capable of recording both sounds and voice. 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 tapes surface. The sound track could be immediately replayed from the same recorder unit, which also contained photoelectric sensors, somewhat similar to the various motion picture sound-on-film technologies of the era.Popular Science. http://books.google.ca/books?id2CcDAAAAMBAJ&pgPA40&lpgPA40#vonepage&q&ffalse 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. http://books.google.ca/books?id2XKQAAAACAAJ Wasnt 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, ISBN 0525475516, ISBN 9780525475514. Article attributed to: Popular Mechanics date of publication unstated, likely c. February 1934. On August 13, 1931, Duston filed USPTO Patent Application #556,743 for "Method Of And Apparatus For Electrically Recording And Reproducing Sound And Other Vibrations", and which was renewed in 1934.USPTO. http://books.google.ca/books?eiuKJ2TOTzM6eCnAek7aCdCw&ctresult&idgCegAAAAMAAJ Official Gazette Of The United States Patent Office], United States Patent Office, 1936, Volume 463, pp.537.

Steel wire magnetic recorder variant

The first wire recorder was the Valdemar Poulsen Telegraphone of the late 1890s, and wire recorders for law/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 the wire recording device 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 Flight recorder 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 1948 quickly drove wire recorders from the market.

Early magnetic tape recorders

Early magnetic taperecorders were created by replacing the wire of a wire recording with a thin steel tape. The first of these modified wire recorders was the Blattnerphone, created in 1929 or 1930 by the Ludwig Blattner Picture Corporation. The first practical tape recorder from AEG was the Magnetophon K1, demonstrated in Germany in 1935. Friedrich Matthias of IG Farben/BASF developed the recording tape, including the oxide, the binder, and the backing material. Development of magnetic tape recorders in the late 1940s and early 1950s is associated with Ampex the equally important development of magnetic tape media itself was led by Minnesota Mining and Manufacturing Company (now known as 3M . :Further information: [[Magnetic tape sound recording#Early steel tape recorders|Further information: Magnetic tape sound recording –Early steel tape recorders]] == Operation == === Electrical === [[Electric current]] flowing in the coils of the tape head creates a fluctuating magnetic field. This causes the magnetic material on the tape, which is moving past and in contact with the head, to align in a manner proportional to the original signal. The signal can be reproduced by running the tape back across the tape head, where the reverse process occurs – the magnetic imprint on the tape [[Faradays law of induction|induces]] a small current in the read head which approximates the original signal and is then amplified for playback. Many tape recorders are capable of recording and playing back at once by means of separate record and playback heads in line or combined in one unit. === Mechanical === Modern professional recorders usually use a three-motor scheme. One motor with a constant rotation speed drives the [[Capstan (tape recorder)|capstan]]. This, usually combined with a rubber pinch roller, ensures that the tape speed does not fluctuate. Of the other two motors, one applies a very light torque to the supply reel, and the other a greater torque to the take-up reel, to maintain the tape tension. During fast winding operation the pinch roller is disengaged and the reel motors provide the necessary power. The cheapest models use a single motor for all required functions; the motor drives the capstan directly and the supply and take-up reels are loosely coupled to the capstan motor with slipping belts or clutches. There are also variants with two motors, in which one motor is used for rewinding only.

Later developments

Image:RadioShack Tape Recorder.jpg ]] Since their first introduction, analog tape recorders have experienced a long series of progressive developments resulting in increased sound quality, convenience, and versatility. * Two-track and, later, multi-track heads permitted discrete recording and playback of individual sound sources, such as two stereophonic channels, or different microphones during live recording. The more versatile machines could be switched to record on some tracks while playing back others, permitting additional tracks to be "laid down" to match previously recorded material such as a rhythm track. * Use of separate heads for recording vs. playback (three heads total, counting the erase head) enabled monitoring of the recorded signal a fraction of a second after recording. Mixing the playback signal back into the record input also created a primitive echo generator. * Dynamic range compression during recording and expansion during playback expanded the available dynamic range and improved the signal-to-noise ratio. dbx and Dolby Laboratories introduced add-on products in this area, originally for studio use, and later in versions for the consumer market. In particular, "Dolby B" noise reduction became very common in all but the least expensive cassette tape recorders.
Image:OpenReel-GMS204.jpg * Computer-controlled analog tape recorders were introduced by Oscar Bonello in Argentina.“A new tape transport system with digital control”, Oscar Bonello, Journal of Audio Engineering Society, Vol 31 # 12, December 1983 The mechanical transport used three DC motors and introduced two new advances: automated microprocessor transport control and automatic adjustment of bias and frequency response In 30 seconds the recorder adjusted its bias for minimum Total harmonic distortion and best frequency response to match the brand and batch of magnetic tape used. The microprocessor control of transport allowed fast location of any point on the tape.

Limitations

The storage of an analog signal on tape works well, but is not perfect. In particular, the granular nature of the magnetic material adds high-frequency noise to the signal, generally referred to as tape hiss. Also, the magnetic characteristics of tape are not linear They exhibit a characteristic hysteresis curve, which causes unwanted distortion of the signal. Some of this distortion is overcome by using an inaudible high-frequency AC Tape bias signal when recording, though the amount of bias needs careful adjustment for best results. Different tape material requires differing amounts of bias, which is why most recorders have a switch to select this (or, in a cassette recorder, switch automatically based on cutouts in the cassette shell). Additionally, systems such as Dolby noise reduction system Dolby C and Dolby HX-Pro have been devised to ameliorate some of the noise and distortion problems. Variations in tape speed cause Flutter (electronics and communication) which can be reduced by using dual capstans. Higher speeds used in professional recorders are prone to cause "head bumps," which are fluctuations in low-frequency response.

Tape recorder variety

There are a wide variety of tape recorders in existence, from small hand-held devices to large multitrack recording machines. A machine with built-in speakers and audio power amplification to drive them is usually called a "tape recorder" or – if it has no record functionality – a "tape player," while one that requires external amplification for playback is usually called a "tape deck" (regardless of whether it can record). Multitrack technology enabled the development of modern art music and one such artist, Brian Eno described the tape recorder as "an automatic musical collage device".

Use of tape recorders

An important use of tape recorders is the recording of video. Videocassette recorder differ substantially from audio recorders due to the use of a rotating magnetic head that uses a helical scan over the tape medium. Helical scans increase the relative speed of the tape surface over the head. While they are primarily used for Sound recording and reproduction tape machines were also important for data storage before the advent of floppy disk and Compact Disc and are still used today, although primarily to provide an offline backup to hard disk drives.

Tapedeck speeds

There are many different tape speeds which are in use in all sorts of tape recorders. Most often these speeds appear on tapedecks. But – while meaning the same speed – many tapedecks are either in Centimetre per second (cm/s) or in inches per second (in/s). To overcome this, here is an overview: | class"wikitable" |- ! cm/s ! in/s |- | 1.2 | 15/32http://www.martelelectronics.com/taperecorderterms.htm Martel Electronics. Terms commonly used for Tape Recorder. Tape Recorder Speed. |- | 2.4 | 15/16 |- | 4.75 | 1 7/8 |- | 9.5 | 3 3/4 |- | 19 | 7 1/2 |- | 38 | 15 |- | 76 | 30 |} :* This article incorporates text from the United States National Museum Bulletin, a government publication in the public domain. By providing a range of tape speeds, users can trade-off recording time against signal quality with higher tape speeds providing greater frequency response.

References

See also: tape formats

* 8-track tape * Cassette deck * Compact Cassette * Digital Audio Tape (DAT) * Elcaset * Helical scan * Reel-to-reel audio tape recording * Wire recording

See also

* Audio editing * Audio format * Digital voice recorder * Electronic music * Electromagnetism * Sound recording and reproduction * Volta Laboratory and Bureau#Sound_recording_and_phonograph_development * Wire recording

External links

* http://www.magnet.fsu.edu/education/tutorials/java/taperecorder/index.html Tape Recorder - Interactive Java Tutorial] National High Magnetic Field Laboratory * http://www.wikirecording.org/Analog_Tape WikiRecordings Guide to Analog Tape] Category:Sound recording technology Category:Sound production technology Category:Audio storage af:Bandopnemer ca:Magnetòfon cs:Magnetofon da:Båndoptager de:Tonbandgerät es:Magnetofón eo:Magnetofono fr:Magnétophone ia:Magnetophono it:Magnetofono he:רשמקול hu:Magnetofon nl:Bandrecorder ja:テープレコーダー pl:Magnetofon pt:Gravador ro:Magnetofon qu:Sinta ruqyay yuyana ru:Магнитофон sq:Magnetofoni sv:Bandspelare uk:Магнітофон zh:磁帶錄音機