Even C tapes were available at one time,  but these were extremely thin and fragile and suffered from such effects as print-through , which made them unsuitable for general use. All of these were discontinued - Maxell simplified its cassette offer to 10, 20, 60 and minute lengths, Sony exited the audio cassette market globally, and Imation , licensee of the TDK trademark, exited the consumer products market.
Some companies included a complimentary blank cassette with their portable cassette recorders in the early s. Panasonic 's was a C14 and came with a song recorded on side one, and a blank side two. Except for C74 and C, 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. The full tape width is 3. For mono recording the track width is 1. In stereo mode each channel has width of 0.
The "head gap" of a tape recorder refers to the space, in the direction of tape movement, between the ends of the pole pieces of the head. Without a gap the head would produce a "closed" magnetic field and so would not interact sufficiently with the magnetic domains on the tape. A narrower gap would give a higher frequency limit but also weaker magnetization. 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.
All cassettes include a write protection mechanism to prevent re-recording and accidental erasure of important material. Each side of the cassette has a plastic tab on the top that may be broken off, leaving a small indentation in the shell. This indentation allows the entry of a sensing lever that prevents the operation of the recording function when the cassette is inserted into a cassette deck. If the cassette is held with one of the labels facing the user and the tape opening at the bottom, the write-protect tab for the corresponding side is at the top-left.
Occasionally and usually on higher-priced cassettes, manufacturers provided a movable panel that could be used to enable or disable write-protect on tapes.
If later required, a piece of adhesive tape can be placed over the indentation to bypass the protection, or on some decks , the lever can be manually depressed to record 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. 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. Leaders can be complex: a plastic slide-in wedge anchors a short fully opaque plastic tape to the take-up hub; one or more tinted semi-opaque plastic segments follow; the clear leader a tintless semi-opaque plastic segment follows, which wraps almost all the way around the supply reel, before splicing to the magnetic tape itself.
The clear leader spreads the shock load to a long stretch of tape instead of to the microscopic splice. Various patents have been issued detailing leader construction and associated tape player mechanisms to detect leaders. 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. 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 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. Cassette tape adapters allow external audio sources to be played back from any tape player, but were typically used for car audio systems. An attached audio cable with a phone connector converts the electrical signals to be read by the tape head, while mechanical gears simulate reel to reel movement without actual tapes when driven by the player mechanism.
This feature each includes a rail to guide the tape to the spool and prevent an unclean roll from forming. 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. Cassette playback suffered from some flaws frustrating to both professionals and home recording enthusiasts.
Tape speed could vary between devices, resulting in pitch that was 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 sometimes be added intentionally to recordings for aesthetic reasons. See Lo-fi music. A common mechanical problem occurred when a worn-out or dirty player rotated the supply spool faster than the take-up spool or failed to release the heads from the tape upon ejection. 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. The first cassette machines e. Early machines required attaching an external dynamic microphone. Most units from the s onwards also incorporated built-in condenser microphones, which have extended high-frequency response, but may also pick up noises from the recorder's motor.
A portable recorder format still common today 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", a vertically pointed triangle with a line under it for "eject", a right-pointing triangle for "play", double triangles for "fast-forward" and "rewind", a red dot 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, often didn't have 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. A major innovation was the front-loading arrangement. Pioneer 's angled cassette bay and the exposed bays of some Sansui models eventually were standardized as a front-loading door into which a cassette would be loaded. Later models would adopt electronic buttons, and replace conventional meters which could be "pegged" when overloaded [ clarification needed ] with electronic LED or vacuum fluorescent displays , with level controls typically being controlled by either rotary controls or side-by-side sliders.
Unlike typical cassette decks that use a single head for both record and playback plus a second head for erasing, the Nakamichi , 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 consumer brand of the Swiss professional Studer company for studio equipment.
Tandberg started with combi-head machines, such as the TCD , and continued with the TCD 3x0 series with separate playback and recording heads. All TCD-models possessed dual-capstan drives, belt-driven from a single capstan motor and two separate reel motors. After a disastrous overinvestment in colour television production, Tandberg folded and revived without the HiFi-branch these came from.
Both cassette units possessed double capstan drives, 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 wearable parts. These machines rivaled the Nakamichi in frequency and dynamic range. A last step taken by Revox produced even more-advanced cassette drives 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 folding its Revox-branch and all its consumer products except their last reel-to-reel recorder, the B While some [ who? Technically, both camps in this debate were still within the original cassette specification as no tolerance for frequency response is provided above 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 s was the radio-cassette, aka the " boom box " a name used commonly only in English-speaking North America , 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, which led to the somewhat derisive nickname "ghetto blaster. This also led to such cultural practises as breakdancing. Applications for car stereos varied widely.
Auto manufacturers in the U. In the s and s, as the cost of building CD players declined, many manufacturers offered a CD player.
The CD player eventually supplanted the cassette deck as standard equipment, but some cars, especially those targeted at older drivers, were offered with the option of a cassette player, either by itself or sometimes in combination with a CD slot. Most new cars can still accommodate aftermarket cassette players, and the auxiliary jack advertised for MP3 players can be used also with portable cassette players, but was the first model year for which no manufacturer offered factory-installed cassette players.
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 , tape-drive capstan, and pinch-roller.
Some otherwise normal recording tapes 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. The Compact Cassette originally was intended for use in dictation machines. The cassette soon became a popular medium for distributing prerecorded music—initially through The Philips Record Company and subsidiary labels Mercury and Philips in the U.
As of , one still finds cassettes used for a variety of purposes, such as journalism , oral history, meeting and interview transcripts, audio-books, and so on. Police are still big buyers of cassette tapes, as some lawyers "don't trust digital technology for interviews". Sleeve City.
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Eject was among the many Autobots who congregated in a secret base during the Age of Internment , when the recently returned Megatron 's Aerospace Extermination Squadron covered the planet Cybertron , capturing countless Autobot heroes and sending the remnants of the army underground. The Age of Wrath Pt. Eject accompanied Blaster as he used an ancient map of Cybertron's depths to infiltrate Megatron's slave camp, only for them to be discovered by Megatron himself.
At a later time, Eject was with Blaster when Optimus rallied the splintered Autobot forces into an organized resistance movement against Shockwave 's totalitarian rule of Cybertron. He presumably participated in the final conflict against the Decepticons and the Guardian robots , bringing the planet back under Autobot control.
Countdown to Extinction. Eject was part of Prowl 's team, working in conjunction with Hawk to round up stray Cybertronian technology on Earth.
When the Autobots disrupted one of Destro 's sales on a dock in Cuba , Eject wound up taking on eight S. While Prowl, Skids , and Sideswipe all fell before the Decepticons' assault Eject carried Firewall to the surface for Cosmos to pick up, before heading below to recharge and help the others. Whether this "help" consisted of single-handedly driving off their attackers is not made clear, but really, his track record points that way. Black Horizon, Part 1 of 2. After Unicron was defeated, Eject happily went back to watching bad television with Firewall.
He was elated when Optimus Prime chose to join them. Black Horizon, Part 2 of 2. As one of the smaller Autobots, he was one of the few original " Builders of Cybertron " who had managed to keep his mobility in energon-starved times.
His position as supervisor of Cybertronian sports, most importantly the gladiatorial Games , allowed him a place of prestige among the elite ruling class. He held onto this sample as leverage should ever have need to placate the Builder Assembly ; a clone of Lio Convoy would also yield a cloned matrix. The Games were fought between Predacons and Maximals, oppressed descendants of Eject's generation.
To ensure that the Games could always be fixed so that the status quo was maintained, Eject took Lio Convoy under his tutelage to do the rigging in person.
His affection towards Lio Convoy was enough that when he learned the Maximal had taken part in some rebellious activities in-between games, Eject used all of his political influence to keep the absent Lio Convoy out of trouble. Though the idea of not being able to fix the upcoming match made him nervous and excited , Eject didn't need to deal with such a situation as Lio Convoy returned to his post before the Game took place. Instead, a much worse scenario arose; Lio Convoy revealed the Builders' selfish motives to the masses, engendering a revolution that swept across the planet.
Protecting Lio Convoy had put Eject in a rather precarious position with the other members of the Builder Assembly. To avoid a horrid fate, Eject presented his "Galva Contingency" plan to his peers. Ratbat and the other assemblymen were receptive to his proposal to create their own pawn to raise a battle-ready army.Sampling cassettes are a convenient way of taking air samples as the filter media are protected and the cassette also doubles up as a transportation device when the sample is sent to the laboratory. Standard styrene cassettes are available either to accept 25mm or 37mm filters in 2 or 3 sections.