Cassette deck
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A cassette deck is a type of tape deck for playing or recording compact audio cassettes.
History
Origins
The cassette recorder was introduced by the Philips Corporation in 1963 and marketed in 1965 as an improvement over reel-to-reel recorders designed for portable use. It enclosed both reels of the recording tape in a small case which eliminated the need to thread the tape through individual reels. The tape width was just 0.125 inches (3.2 mm) and tape speed was 1.875 inches (4.76 cm) per second, which meant that sound quality was appropriate only for voice or dictation use at the time.Early recorders tended to be small battery-powered portable devices, in keeping with the intention of the medium for dictation, reportage and similar low-level recording duties, but by the mid 1970s, the cassette deck became a commonplace component of home high fidelity systems, largely superseding the reel-to-reel recorder for home use.In 1971, the Advent Corporation combined Dolby B-type tape-hiss-noise reduction system with chromium dioxide tape to create the Advent Model 201, the first high-fidelity cassette deck. This deck was an OEM unit manufactured by Nakamichi.
Widespread use
Cassette decks soon came into widespread use and were designed variously for professional applications, home audio systems, and for mobile use in cars, as well as portable recorders. From the mid 1970s to the late 1990s the cassette deck was the preferred music source for the automobile. Like an 8-track cartridge, it was relatively insensitive to vehicle motion, but it had superior frequency response and reduced tape flutter, as well as the obvious advantages of smaller physical size and fast forward/rewind capability.
Performance improvements
Cassette decks reached their pinnacle of performance and complexity by the mid 1980s. Cassette decks from companies such as Nakamichi, Revox, and Tandberg incorporated advanced features such as multiple tape heads and dual capstan drive without motorized reel motors. Auto-reversing decks came into popular use so the user did not need to flip the cassette manually to play the second side of the tape. Compact Decks sold by Japanese companies such as Akai, Pioneer, Sony, Technics, Yamaha, and Denon were also common, with each company offering models of very high quality.
The best cassette decks use three-head technology (developed by Nakamichi but used on top decks from all manufacturers), the Dolby noise reduction system including the newer C (in 1980) and S types, and microprocessors to adjust tape bias automatically. Bang & Olufsen developed the HX-Pro headroom extension system in conjunction with Dolby Laboratories in 1982. This was used in many higher-end decks. Manufacturers experimented with exotic tape formulations to improve high frequency response. Sony used a dual layer formulation known as Ferri-chrome.;
Noise reduction and fidelity
A variety of noise reduction and other schemes are used to increase fidelity, Dolby B being almost universal for both prerecorded tapes and home recording. Later enhancements included Dolby C and Dolby S noise reduction, Dolby HX Pro headroom extension, the dbx and DNR noise reduction systems, automatic bias setting, and on some high-end decks, automatic head azimuth adjustment. Dolby HX Pro, which was developed by Bang & Olufsen, is a system that dynamically alters the bias during recording to yield a substantial improvement in high-frequency response during playback, regardless of the playback system.
By the late 1980s, thanks to such improvements in the electronics, the tape material and manufacturing techniques, as well as dramatic improvements to the precision of the cassette shell, tape heads and transport mechanics, sound fidelity on equipment from the top manufacturers far surpassed the levels originally expected of the medium. On suitable audio equipment, cassettes could produce a very pleasant listening experience. The best home decks could achieve 20 Hz-20 kHz frequency response with wow and flutter below 0.05%, and 70 dB of signal-to-noise ratio using Dolby C and up to 80 dB of signal-to-noise ratio using Dolby S.
Average equipement achieves 30 Hz-15 kHz frequency response with wow and flutter below 0.1%, and least 55dB of signal-to-noise ratio using no Dolby noise reduction, 63dB of signal-to-noise ratio using Dolby B and 70dB of signal-to-noise ratio using Dolby C. Usage of Type II tapes improves signal-to-noise ratio by 2dB and Type IV gives an extra 1dB.
In the 1990's, Dolby S noise reduction was introduced to the compact cassette, derived from Dolby SR, a professional system. Whereas the Dolby B and C Noise Reduction would dynamically adjust the preemphasis to promote a lower noise floor for high frequencies, Dolby S worked across the frequency range. However, licensing restrictions meant that Dolby S was only available on higher end tape decks that included dual motors, triple heads and other refinements. This system, according to a double blind study conducted by Stereo Review, yielded more accurate results than MiniDisc.
Prior to the mid 1980's pre-recorded cassettes were often of poor sound quality mainly due to the high speed duplication process used to produce them. However, technologies such as XDR (a quality control system), Dolby B Noise Reduction, Dolby HX pro and chrome dioxide tape meant that pre-recorded cassettes were soon approaching vinyl records in terms of audio quality and outselling LP records in some markets.
In-car entertainment systems
Another key element of the cassette's success was its use in in-car entertainment systems, where the small size of the tape was significantly more convenient than the competing 8-track cartridge system. Cassette players in cars and for home use were often integrated with a radio receiver, and the term "casseiver" was occasionally used for combination units for home use. In-car cassette players were the first to adopt the idea of automatic reversal ("auto-reverse") of the tape at each end, allowing a cassette to be played endlessly without manual intervention. Home cassette decks soon followed this practice as well.Later on Cassette tape adaptors were developed, allowing newer forms of music player to be used with existing cassette-based systems, including those in cars. (See "Successors to the cassette" below).
Companies such as Tandberg, ReVox, Nakamichi, Akai, Aiwa, Technics, Pioneer and Sony made highly advanced cassette decks for high-end audio systems. Some include three-head technology for off-tape monitoring.
Maintenance
Cassette equipment needs regular maintenance, as cassette tape is a magnetic medium which is in physical contact with the tape head and other metallic parts of the recorder/player mechanism. Without such maintenance, the high frequency response of the cassette equipment may suffer.
One problem occurs when iron oxide (or similar) particles from the tape itself become lodged in the read head. As a result, the tape heads will require occasional cleaning to remove such particles. The metal capstan and the rubber pinch roller can become coated with these particles, leading them to pull the tape less precisely over the head; this in turn leads to misalignment of the tape over the head azimuth, producing noticeably unclear high tones, just as if the head itself were out of alignment.
In addition, the heads and other metallic components in the tape path (such as spindles and capstans) may become magnetised, and require demagnetization. Both Cassette demagnetizers and head-cleaning fluid are available. Isopropyl alcohol is commonly used as a tape head cleaner.
Decline in popularity
Analog cassette deck sales began to decline with the advent of the compact disc and other digital recording technologies such as digital audio tape (DAT). Philips responded with the digital compact cassette, but it failed to garner a significant market share and was withdrawn. Tascam, Marantz, Yamaha, Teac, Denon, Sony, and JVC are among the companies still manufacturing cassette decks in relatively small quantities for professional and niche market use.
Despite the decline in the production of cassette decks, these products are still valued by some. Some audiophiles believe that cassette deck technology, due to its analog nature, provides sound recordings superior to current digital technology, such as CDR and DAT. However, cassette decks are not considered by most people today to be either the most versatile or highest fidelity sound recording devices available.
See also
- Tape deck
- Nakamichi and Revox. These corporate pages contains links to external sites relevant to cassette decks.
- high end audio. This page contains links to high-end audio companies, including companies formerly producing "high-end" audio gear such as cassette decks.
External links
- [Pictures of Cassette Decks] – A Japanese language page, but containing pictures of historic cassette decks.
- [Vintage Deck Pictures] – An external link with pictures of vintage cassette decks and reel to reel decks.
- [Audio Asylum Tape Trail] – A discussion forum of interest to those involved in cassette technology.
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