Talk:Cassette tape/Archive 5

Uncited material in need of citations
I am moving the following uncited material here until it can be properly supported with inline citations of reliable, secondary sources, per WP:V, WP:NOR, WP:CS, WP:NOR, WP:IRS, WP:PSTS, et al. This diff shows where it was in the article. Nightscream (talk) 16:07, 3 September 2022 (UTC)

Precursors
In 1935, AEG released the first reel-to-reel tape recorder with the commercial name "Magnetophon". It was based on the invention of the magnetic tape by Fritz Pfleumer in 1928. These machines were very expensive and relatively difficult to use and were, therefore, used mostly by professionals in radio stations and recording studios.

The cartridge was large at 5 x 7 1/8 x 1/2 inches (127 x 197 x 13 mm), and few pre-recorded tapes were offered. Despite the multiple versions, it failed.

Consumer use of magnetic tape machines took off in the early 1960s, after playback machines reached a comfortable, user-friendly design. This was aided by the introduction of transistors which replaced the bulky, fragile, and costly vacuum tubes of earlier designs. Reel-to-reel tape then became more suitable for household use, but still remained an esoteric product.

Introduction
The Belgian team created a two-spool cartridge similar to an earlier RCA design, but much smaller.

Decline
By the early 2000s, the CD player rapidly replaced the cassette player as the default audio component in the majority of new vehicles in Europe and America.

Most of the major US music companies had discontinued production of pre-recorded cassettes by 2003.

Many out-of-print titles, such as those published during the cassette's heyday of the 1970s to early 2000s, are only available on the original cassettes.

Cassette types
Inexpensive cassettes commonly are labeled "low-noise", but typically are not optimized for high frequency response. For this reason, some low-grade IEC Type I tapes have been marketed specifically as better suited for data storage than for sound recording.

Simple voice recorders and earlier cassette decks are designed to work with standard ferric formulations. Newer tape decks usually are built with switches and later detectors for the different bias and equalization requirements for higher grade tapes. The most common, iron oxide tapes (defined by the IEC 60094 standard, as "Type I") use 120 microsecond (µs) equalization, while chrome and cobalt-adsorbed tapes (IEC Type II) require 70 µs equalization. The recording bias levels also were different. BASF and Sony tried a dual-layer tape with both ferric oxide and chromium dioxide known as ferrichrome (FeCr) (IEC Type III), but these were available for only a short time in the 1970s. These also use 70 µs, just like Type II did. Metal cassettes (IEC Type IV) also use 70 µs equalization, and provide still further improvement in sound quality as well as durability. The quality normally is reflected in the price; Type I cassettes generally are the cheapest, and Type IV are usually the most expensive. BASF chrome tape used in commercially pre-recorded cassettes used Type I equalization to allow greater high-frequency dynamic range for better sound quality, but the greater selling point for the music labels was that the Type I cassette shell could be used for both ferric and for chrome music cassettes.

Notches on top of the cassette shell indicate the type of tape. Type I cassettes have only write-protect notches, Type II have an additional pair next to the write protection ones, and Type IV (metal) have a third set near the middle of the top of the cassette shell. These allow later cassette decks to detect the tape type automatically and select the proper bias and equalization.

An exception to this standard were mechanical storytelling dolls from the 1980s (e.g. Teddy Ruxpin) which used the Type IV metal configuration cassette shell but had normal Type I voice grade tape inside. These toys used the Type IV notches to detect that a specially coded tape had been inserted, where the audio of the story is stored on the left channel and various cue tones to tell the doll's servos how and when to move along with the story on the right channel.

Most pre-recorded chrome cassettes require 120 µs equalization and are treated as Type I (with notches as Type I ferric cassettes), to ensure compatibility with budget equipment.

Tape length
However, C180 tapes were extremely thin and fragile and suffered from such effects as print-through, which made them unsuitable for general use.

150 minute length cassettes were available from Maxell (UR 150), Sony (CDixI 150) and TDK (TDK AE 150, CDing1 150 and CDing2 150), only in Japan. All of these were discontinued - Maxell simplified its cassette offer to 10, 20, 60 and 90-minute lengths, Sony exited the audio cassette market globally, and Imation, licensee of the TDK trademark, exited the consumer products market.

Most manufacturers load more tape that a label indicates, for example 90 m rather than 86 m of tape for a C60 cassette, and 132 or rather than 129 m of tape for a C90 cassette, providing an extra minute or two of playback time per side.

Some companies included a complimentary blank cassette with their portable cassette recorders in the early 1980s. Panasonic's was a C14 and came with a song recorded on side one, and a blank side two. Except for C74 and C100, such non-standard lengths always have been hard to find, and tend to be more expensive than the more popular lengths. Home taping enthusiasts may have found certain lengths useful for fitting an album neatly on one or both sides of a tape. For instance, the initial maximum playback time of Compact Discs was 74 minutes, explaining the relative popularity of C74 cassettes.

150 minute length cassettes were available from Maxell (UR 150), Sony (CDixI 150) and TDK (TDK AE 150, CDing1 150 and CDing2 150), only in Japan. All of these were discontinued - Maxell simplified its cassette offer to 10, 20, 60 and 90-minute lengths, Sony exited the audio cassette market globally, and Imation, licensee of the TDK trademark, exited the consumer products market.

Head gap
The head gap of a tape recorder is the space, along the tape path, between the ends of the pole pieces of the head. Without a gap the head would produce a "closed" magnetic field and would not interact enough with the magnetic domains on the tape.

However, such limitations can be corrected through equalization in the recording and playback amplification sections, and narrower gaps were quite common, particularly in more expensive cassette machines. For example, the RP-2 series combined record/playback head (used in many Nakamichi cassette decks from the 1980s and 1990s) had a 1.2 µm gap, which allows for a playback frequency range of up to 20 kHz. A narrower gap width makes it harder to magnetize the tape, but is less important to the frequency range during recording than during playback, so a two-head solution can be applied: a dedicated recording head with a wide gap allowing effective magnetization of the tape and a dedicated playback head with a specific width narrow gap, possibly facilitating very high playback frequency ranges well above 20 kHz.

Separate record and playback heads were already a standard feature of more expensive reel-to-reel tape machines when cassettes were introduced, but their application to cassette recorders had to wait until demand developed for higher quality reproduction, and for sufficiently small heads to be produced.

Write-protection
Most cassettes include a write protection mechanism to prevent re-recording and accidental erasure of important material. There are two indentations on the top of a cassette corresponding to each side of the cassette. On blank cassettes these indentations are protected with plastic tabs that can be broken off to prevent recording on the corresponding side of the cassette. Occasionally and usually on higher-priced cassettes, manufacturers provided a movable panel that could be used to enable or disable write-protect on tapes. Pre-recorded cassettes do not have protective tabs, leaving the indentations open.

If later required, the cassette can be made recordable again by either covering the indentation with a piece of adhesive tape or by putting some filler material into the indentation. On some decks, the write-protect sensing lever can be manually depressed to allow recording on a protected tape. Extra care is required to avoid covering the additional indents on high bias or metal bias tape cassettes adjacent to the write-protect tabs.

Tape leaders
In most cassettes, the magnetic tape is attached to each spool with a leader, usually made of strong plastic. This leader protects the weaker magnetic tape from the shock occurring when the tape reaches the end. Some leaders are designed to clean the magnetic heads each time the tape is played. Leader also enables to record over an existing recording cleanly, without a blip of sound that otherwise would be left from the previous recording.

Cassette tape users would also use spare leaders to repair broken tapes.

The disadvantage with tape leaders is that the sound recording or playback does not start at the beginning of the tape, forcing the user to cue forward to the start of the magnetic section. For certain applications, such as dictation, special cassettes containing leaderless tapes are made, typically with stronger material and for use in machines that had more sophisticated end-of-tape prediction. Home computers that made use of cassettes as a more affordable alternative to floppy discs (e.g. Apple II, Commodore PET) were designed to not start writing or reading data until leaders had spooled past.

Endless loop cassette
Some cassettes were made to play a continuous loop of tape without stopping. Lengths available are from around 30 seconds to a standard full length. They are used in situations where a short message or musical jingle is to be played, either continuously or whenever a device is triggered, or whenever continuous recording or playing is needed. Some include a sensing foil on the tape to allow tape players to re-cue. From as early as 1969 various patents have been issued, covering such uses as uni-directional, bi-directional, and compatibility with auto-shut-off and anti-tape-eating mechanisms. One variant has a half-width loop of tape for an answering machine outgoing message, and another half-width tape on spools to record incoming messages.

Optional mechanics
The competition responded by inserting additional deflector pins closer to the coils in the lower plastic case half. Some low-priced and pre-recorded compact cassettes were made without pulleys; the tape is pulled directly over the capstan drive. For the pressure of the tape to the head there is a thinner felt on a glued foam block instead of the usual felt on a leaf spring.

Flaws
Cassette playback has suffered from some flaws frustrating to both professionals and home recording enthusiasts. Tape speed varies between devices, resulting in pitch that is too low or too high. Speed often was calibrated at the factory and could not be changed by users. The slow tape speed increased tape hiss and noise, and in practice delivered higher values of wow and flutter. Different tape formulation and noise reduction schemes artificially boosted or cut high frequencies and inadvertently elevated noise levels. Noise reduction also adds some artifacts to the sound which a trained ear can hear, sometimes quite easily. Wow and flutter, however, can be added to recordings intentionally for aesthetic reasons.

A common mechanical problem occurred when a defective player or resistance in the tape path causes insufficient tension on the take-up spool. This would cause the magnetic tape to be fed out through the bottom of the cassette and become tangled in the mechanism of the player. In these cases, the player was said to have "eaten" or "chewed" the tape, often destroying the playability of the cassette. Splicing blocks, analogous to those used for open-reel 1/4" tape, were available and could be used to remove the damaged portion or repair the break in the tape.

Cassette players and recorders
were simple mono record and playback units. Early machines required attaching an external dynamic microphone. Most units from the 1980s onwards also incorporated internal electret microphones, which have extended high-frequency response, but may also pick up noises from the recorder's motor.

A common portable recorder format is a long box, the width of a cassette, with a speaker at the top, a cassette bay in the middle, and "piano key" controls at the bottom edge. Another format is only slightly larger than the cassette, known popularly as the "Walkman" (a Sony trademark).

The markings of "piano key" controls soon converged and became a de facto standard. They are still emulated on many software control panels. These symbols are commonly a square for "stop", an upward-pointed, underlined triangle for "eject", a right-pointing triangle for "play", a rightward-facing pair of triangles for "fast forward" with leftward-facing doubled triangles for "rewind", a dot, sometimes colored red, or, occasionally, a red LED, for "record", and a vertically divided square (two rectangles side-by-side) for "pause".

Stereo recorders eventually evolved into high fidelity and were known as cassette decks, after the reel-to-reel decks. Hi-Fi cassette decks, in contrast to cassette recorders and cassette players, generally omit built-in amplification or speakers. Many formats of cassette players and recorders have evolved over the years. Initially all were top loading, usually with cassette on one side, and VU meters and recording level controls on the other side. Older models used combinations of levers and sliding buttons for control.

The 3-head closed-loop dual-capstan Nakamichi 1000 (1973) is one early example. Unlike typical cassette decks that use a single head for both record and playback plus a second head for erasing, the Nakamichi 1000, like the better reel-to-reel recorders, used three separate heads to optimize these functions.

Other contenders for the highest "HiFi" quality on this medium were two companies already widely known for their excellent quality reel-to-reel tape recorders: Tandberg and Revox (the consumer marque of Swiss studio equipment manufacturer Studer). Tandberg started with combined-head machines, such as the TCD 300, and continued with the TCD 3x0 series with separate playback and recording heads. All TCD models used dual-capstan mechanisms, belt-driven by a single capstan motor and two separate reel motors. Frequency range extended to 18 kHz. After a disastrous overinvestment in colour television production, Tandberg folded and was revived without the HiFi division that made these recorders.

Revox went one step further: after much hesitation about whether to accept cassettes at all as a medium capable of meeting their strict standards from reel-to-reel recorders, they produced their B710MK I (Dolby B) and MK II (Dolby B&C) machines. Both cassette units employed dual-capstan mechanisms, but with two independent, electronically controlled capstan motors and two separate reel motors. The head assembly moved by actuating a damped solenoid movement, eliminating all belt drives and other wearing parts. These machines rivaled the Nakamichi in frequency and dynamic range. The B710MKII also achieved 20–20,000 Hz and dynamics of over 72 dB with Dolby C on chrome and slightly less dynamic range, but greater headroom, with metal tapes and Dolby C. Revox adjusted the frequency range on delivery with many years of use in mind: when new, the frequency curve went upwards a few dB at 15–20 kHz, aiming for flat response after 15 years of use, and head wear to match.

A last step taken by Revox produced even more-advanced cassette mechanisms with electronic fine tuning of bias and equalization during recording. Revox also produced amplifiers, a very expensive FM tuner, and a pickup with a special parallel-arm mechanism of their own design. After releasing that product, Studer encountered financial difficulties. It had to save itself by closing its Revox division, thus discontinuing all its consumer products other than their final reel-to-reel recorder, the B77.

This advanced method is called Dolby HX Pro in full and is patented. HX Pro was adopted by many other high-end manufacturers.

As they became aimed at more casual users, fewer decks had microphone inputs. Dual decks became popular and incorporated into home entertainment systems of all sizes for tape dubbing. Although the quality would suffer each time a source was copied, there are no mechanical restrictions on copying from a record, radio, or another cassette source. Even as CD recorders are becoming more popular, some incorporate cassette decks for professional applications.

Another format that made an impact on culture in the 1980s was the radio-cassette, aka the "boom box" (a name used commonly only in North American dialects of English), which combined the portable cassette deck with a radio tuner and speakers capable of producing significant sound levels. These devices became synonymous with urban youth culture in entertainment, leading to the nickname "ghetto blaster". The boom box also allowed people to enjoy music on the go and share it with friends, contributing to cultural practises such as breakdancing.

Although the cassettes themselves were relatively durable, the players required regular maintenance to perform properly. Head cleaning may be done with long swabs, soaked with isopropyl alcohol, or cassette-shaped devices that could be inserted into a tape deck to remove buildup of iron oxide from the heads, capstan, and pinch roller. Some otherwise normal blank cassettes included sections of leader that could clean the tape heads. One of the concerns of the time however was the use of abrasive cleaning tape. Some of the cleaning tapes actually felt rough to the touch and were considered damaging to the heads. Similarly shaped demagnetizers used magnets to degauss the deck, which kept sound from becoming distorted (see cassette demagnetizer).

Broadcasting
News reporting, documentary, and human interest broadcast operations often used portable Marantz PMD-series recorders for the recording of speech interviews. The key advantages of the Marantz portable recorders were the accommodation of professional microphones with an XLR connector, normal and double tape speed recording for extended frequency response, Dolby and dbx noise reduction systems, manual or automatic gain control (AGC) level control, peak limiter, multiple tape formulation accommodation, microphone and line level input connections, unbalanced RCA stereo input and output connections, live or tape monitoring, VU meter, headphone jack, playback pitch control, and operation on AC power or batteries optimized for long duration. Unlike less-expensive portable recorders that were limited to automatic gain control (AGC) recording schemes, the manual recording mode preserved low noise dynamics and avoided the automatic elevation of noise.

Home studio
Beginning in 1979, Tascam introduced the Portastudio line of four- and eight-track cassette recorders for home-studio use.

Although professional musicians typically used multitrack cassette machines only as "sketchpads" to create demo recordings, Bruce Springsteen's Nebraska was recorded entirely on a four-track cassette tape.

Home dubbing
Albums in this format were prerecorded on one side and the other was left blank for the purchaser to use, another early example being the 1980 "C·30 C·60 C·90 Go" cassingle by Bow Wow Wow where the b-side of the tape was blank, allowing the purchaser to record their own b-side. Cassettes were also a boon to people wishing to tape concerts (unauthorized or authorized) for sale or trade, a practice tacitly or overtly encouraged by many bands, such as the Grateful Dead, with a more counterculture bent. Blank cassettes also were an invaluable tool to spread the music of unsigned acts, especially within tape trading networks.

Institutional duplication
Educational, religious, corporate, military, and broadcasting institutions benefited from messaging proliferation through accessibly priced duplicators, offered by Telex Communications, Wollensak, Sony, and others. The duplicators would operate at double (or greater) tape speed. Systems were scalable, enabling the user to purchase initially one "master" unit (typically with 3 "copy" bays) and add "slave" units for expanded duplication abilities.

Data recording
The Hewlett-Packard HP 9830 was one of the first desktop computers in the early 1970s to use automatically controlled cassette tapes for storage. It could save and find files by number, using a clear leader to detect the end of tape. These would be replaced by specialized cartridges, such as the 3M DC-series. Many of the earliest microcomputers implemented the Kansas City standard for digital data storage. Most home computers of the late 1970s and early 1980s could use cassettes for data storage as a cheaper alternative to floppy disks, though users often had to manually stop and start a cassette recorder. Even the first version of the IBM PC of 1981 had a cassette port and a command in its ROM BASIC programming language to use it. However, IBM cassette tape was seldom used, as by 1981 floppy drives had become commonplace in high-end machines.

Nintendo's Famicom had an available cassette data recorder, used for saving programs created with the hardware's version of BASIC and saving progress in some Famicom games. It was never released outside Japan, but the North American versions of some of the compatible games can technically be used with it, since many early copies of two of the games (Excitebike and Wrecking Crew) are actually just the Japanese versions in a different shell, and Nintendo intentionally included compatibility in later prints of those titles and in other games since they were planning on releasing the recorder in the region anyway.

The typical encoding method for computer data was simple FSK, typically at data rates of 500 to 2000 bit/s, although some games used special, faster-loading routines, up to around 4000 bit/s. A rate of 2000 bit/s equates to a capacity of around 660 kilobytes per side of a 90-minute tape.

Among home computers that used primarily data cassettes for storage in the late 1970s were Commodore PET (early models of which had a cassette drive built-in), TRS-80 and Apple II, until the introduction of floppy disk drives and hard drives in the early 1980s made cassettes virtually obsolete for day-to-day use in the US. However, they remained in use on some portable systems such as the TRS-80 Model 100 line—often in microcassette form—until the early 1990s.

The use of better modulation techniques, such as QPSK or those used in modern modems, combined with the improved bandwidth and signal-to-noise ratio of newer cassette tapes, allowed much greater capacities (up to 60 MB) and data transfer speeds of 10 to 17 kbit/s on each cassette. They found use during the 1980s in data loggers for scientific and industrial equipment.

Video
The PXL-2000 was a camcorder that recorded onto compact cassettes.

Rivals and successors
Elcaset is a short-lived audio format that was created by Sony in 1976 that is about twice the size, using larger tape and a higher recording speed. Unlike the original cassette, the Elcaset was designed for sound quality. It was never widely accepted, as the quality of standard cassette decks rapidly approached high fidelity.