The original format for magnetic tape sound reproduction was the reel-to-reel tape recorder, first available in the US in the late 1940s, but too expensive and bulky to be practical for amateur home use until well into the 1950s. Loading a reel of tape onto the machine and threading it through the various guides and rollers proved daunting to some casual users—certainly, it was more difficult than putting a vinyl record on a record player and flicking a switch. Because in early years each tape had to be dubbed from the master tape in real-time to maintain good sound quality, prerecorded tapes were more expensive to manufacture, and costlier to buy, than vinyl records which could be stamped much quicker than their own playing time.
To eliminate the nuisance of tape-threading, various manufacturers introduced cartridges that held the tape inside a metal or plastic housing to eliminate handling. Most were intended only for low-fidelity voice recording in dictation machines. The first tape cartridge designed for general consumer use, including music reproduction, was the Sound Tape or Magazine Loading Cartridge (RCA tape cartridge), introduced in 1958 by RCA. Prerecorded stereophonic music cartridges were available, and blank cartridges could be used to make recordings at home, but the format failed to gain popularity.
The endless loop tape cartridge was first designed in 1952 by Bernard Cousino around a single reel carrying a continuous loop of standard 1/4-inch, plastic, oxide-coated recording tape running at 3.75 in (10 cm) per second. Program starts and stops were signaled by a one-inch-long metal foil that activates the track-change sensor. (Bill Lear had tried to create an endless-loop wire recorder in the 1940s, but gave up in 1946. He would be inspired by Earl Muntz's four-track design in the early 1960s.)
Inventor George Eash invented a cartridge design in 1953, called the Fidelipac cartridge. The Eash cartridge was later licensed by manufacturers, notably the Collins Radio Company, which first introduced a cartridge system for broadcasting at the National Association of Broadcasters 1959 annual show. Fidelipac cartridges (nicknamed "carts" by DJs and radio engineers) were used by many radio stations for commercials, jingles, and other short items. Eash later formed Fidelipac Corporation to manufacture and market tapes and recorders, as did several others, including Audio-Pak (Audio Devices Corp.).
There were several attempts to sell music systems for cars, beginning with the Chrysler Highway Hi-Fi of the late 1950s (which used discs). Entrepreneur Earl "Madman" Muntz of Los Angeles, California, however, saw a potential in these "broadcast carts" for an automobile music system. In 1962 he introduced his Stereo-Pak four-track cartridge stereo system and tapes, mostly in California and Florida. The four tracks were divided into two "programs", typically corresponding to the two sides of an LP record, with each program comprising two tracks read simultaneously for stereo playback. He licensed popular music albums from the major record companies and duplicated them on these four-track cartridges, or "CARtridges", as they were first advertised.
The Lear Jet Stereo 8 track cartridge was designed by Richard Kraus while working under Bill Lear and for his Lear Jet Corporation in 1963. The major change was to incorporate a neoprene rubber and nylon pinch roller into the cartridge itself, rather than to make the pinch roller a part of the tape player, reducing mechanical complexity. Lear also eliminated some of the internal parts of the Eash cartridge, such as the tape-tensioning mechanism and an interlock that prevented tape spillage. By doubling the number of tracks from 4 to 8, the recording length doubled to 80 minutes.
In 1964, Lear's aircraft company constructed 100 demonstration Stereo 8 players for distribution to executives at RCA and the auto companies.
The popularity of both four-track and eight-track cartridges grew from the booming automobile industry. In September 1965, Ford Motor Company introduced factory-installed and dealer-installed eight-track tape players as an option on three of its 1966 models (Mustang, Thunderbird, and Lincoln), and RCA Victor introduced 175 Stereo-8 Cartridges from its RCA Victor and RCA Camden artist's catalogs. By the 1967 model year, all of Ford's vehicles offered this tape player upgrade option. Most of the initial factory installations were separate players from the radio (such as shown in the image), but dashboard mounted 8-track units were offered in combination with an AM radio, as well as with AM/FM receivers. Muntz, and a few other manufacturers, also offered 4/8 or "12-track" players that were capable of playing cartridges of either format, 4-track or 8-track. With the backing of the US automakers, the eight-track format quickly won out over the four-track format, with Muntz abandoning it completely by late 1970.
Despite its problems, the format gained steady popularity because of its convenience and portability. Home players were introduced in 1966 that allowed consumers to share tapes between their homes and portable systems. By the late 1960s, the 8-track segment was the largest in the consumer electronics market and the popularity of 8-track systems for cars helping generate demand for home units. "Boombox" type players were also popular but eight-track player/recorders failed to gain wide popularity and few manufacturers offered them. With the availability of cartridge systems for the home, consumers started thinking of eight-tracks as a viable alternative to vinyl records, not only as a convenience for the car. Within a year, prerecorded releases on eight-track began to arrive within a month of the vinyl release. The eight-track format became by far the most popular and offered the largest music library of all the tape systems.
Eight-track players were fitted as standard equipment in most Rolls-Royce and Bentley cars of the period for sale in UK and world-wide. Optional 8-track players were available in many cars and trucks through the early 1980s.
Ampex, based in Elk Grove Village, Illinois, set up a European operation (Ampex Stereo Tapes) in London, England, in 1970 under general manager Gerry Hall, with manufacturing in Nivelles, Belgium, to promote 8-track product (as well as musicassettes) in Britain and in Europe, but it struggled and folded in 1974.
Quadraphonic eight-track cartridges (announced by RCA in April 1970) were also produced, Ford being particularly eager to promote in-car quadraphonic players as a pricey option. Neither Chrysler, General Motors, nor American Motors ever offered a quadraphonic tape player. The format enjoyed a moderate amount of success for a time but faded in the mid-1970s. These cartridges are sought by collectors since they provide four channels of discrete sound, unlike matrixed formats such as SQ, which Columbia/CBS Records used for their quadraphonic vinyl records.
Daisuke Inoue invented the first karaoke machine in 1971 called the Juke-8.
Eight-track players became less common in homes and vehicles in the late 1970s. The compact cassette arrived in 1962, and by the 1970s the eight-track cartridges had greatly diminished in popularity. In some Latin American countries as well as European, the format was abandoned in the mid-1970s in favor of the cassette. The UK never had as much use as the compact cassette in cars and home players were almost unknown in the UK.
In the US, eight-track cartridges were phased out of retail stores by late 1982. Some titles were still available as eight-track tapes through Columbia House and RCA (BMG) Music Service Record Clubs until late 1988. Many of these late-period releases are highly collectible because of the low numbers that were produced and the few customers who ever purchased them. Among the most rare is Stevie Ray Vaughan's Texas Flood. Another is Bruce Springsteen and the E Street Band's Live/1975-85, which was one of the very few boxed sets to be released on vinyl, cassette, compact disc, and eight-track tape.
There is a debate among collectors about the last commercial eight-track released by a major label, but the fan website 8 Track Heaven cannot find a major label release past Fleetwood Mac's Greatest Hits in November 1988.
The professional broadcast cart format survived for more than another decade at most radio stations. It was used to play and switch jingles, advertisements, station identifications, and music content until it was replaced by various computer-based methods in the 1990s. This format survived longer because it was used for relatively short sound loops, where starting from the beginning was more important than other criteria. The endless loop tape concept continues to be used in modern movie projectors, although in that application the spool is actively rotated and not drawn by tension on the film. That too, however, is being supplanted by digital cinema technologies.
Some independent artists still release eight-track tapes, such as the US band RTB2, who released We Are a Strange Man in 2011. Also, bands sometimes release eight-tracks as special releases; for example, The Melvins released a limited-time, live eight-track album, Cheap Trick issued a limited edition version of their album The Latest on the format on June 23, 2009, and power electronics solo artist Waves Crashing Piano Chords has released multiple eight-track tapes since 2012, as well as starting an eight-track tape label, H8-Track Stereo. In the book Journals, Kurt Cobain wrote about wanting to release Nirvana's album In Utero as an 8-track tape, but this never happened. Apart from a select group of highly collectible artists, the record club issues, and the quadraphonic releases, many eight-track tapes seem to have limited value to most collectors, especially if the tapes have been misused or appear to be worn.
In the Cousino, Eash, Muntz, and Lear cartridges, tape was pulled from the center of the reel, passed across the opening at one end of the cartridge and wound back onto the outside of the same reel. The spool itself was freewheeling and the tape was driven only by tension from the capstan and pinch roller.
With a reel turning at a constant rate, the tape around the hub has a lower linear velocity than the tape at the outside of the reel, so the tape layers must slip past each other as they approach the center. The tape was coated with a slippery backing material, usually graphite and patented by Bernard Cousino, to ease the continuous slip between the tape layers. While the design allowed simple, cheap, and mobile players, unlike a two-reel system, it did not permit rewinding of the tape. Some players offered fast-forward by speeding up the motor while cutting off the audio; but rewinding was never offered, because it was technically impossible.
Muntz's cartridge had used two pairs of stereo tracks in the same configuration as then-current "quarter track" reel-to-reel tapes. This format was intended to parallel his source material, which was usually a single LP (long playing) record with two sides. Program switching was achieved by physically moving the head up and down mechanically by a lever. The Stereo 8 version doubled the amount of programming on the tape by providing eight total tracks, usually comprising four programs of two tracks each. Lear touted this as a great improvement, because much more music could be held inside a standard cartridge housing, but in practice this resulted in a slight loss of sound quality and an increase in background noise from the narrower tape tracks. Unlike the Stereo-Pak, the Stereo 8 could switch between tracks automatically, with the use of a small length of conductive foil at the splice joint on the tape, which would cause the player to change tracks as it passed the head assembly.
The cartridges have an audible pause due to the presence of a length of metallic foil, which a sensor detects and signals the end of the tape and acts as a splice for the loop. The foil passes across a pair of electrical contacts which are in the tape path. Contact of the foil closes an electrical circuit that engages a solenoid which mechanically shifts the tape head to the level of the next track.
Most players produced a mechanical click when switching programs, although early Lear players switched silently. Because of the expense of producing tape heads capable of reading eight tracks, most eight-track players have heads that read just two tracks. Switching from program to program is accomplished by moving the head itself. Since the alignment of the head to the tape is crucial to any tape system, and because eight-track systems were generally designed to be cheap, this configuration further degraded the sound of the eight-track tape.
The Stereo 8 system was fairly simple, mechanically, but presented difficulties in various primary areas:Capstan wear and buildup. As tape residue, dirt and lubricant built up on the capstan, the tape speed would increase and, since the buildup was uneven, the tape speed would become correspondingly uneven. Similarly, some units were subject to the capstan wear, causing a decrease in tape speed. Technicians routinely kept a supply of new capstans on hand ready to install into worn decks for this reason, during the heyday of the format. Once the capstan wears only .001" the tape speed slows. Replacing or resurfacing the capstan would restore operation. The old "matchpack" or "matchbook" under the tape fix while playing, was done primarily because the capstan was worn or polished, and would no longer grip the tape and play it at the correct speed. Replacing or resurfacing the capstan, restores proper operation without using a wedge under the tape.
Head alignment. This was an issue for two reasons: a) Azimuth misalignment results in reduced high frequencies, and b) Head height misalignment allows sounds from adjacent tracks to bleed over, an effect sometimes known as "double-tracking". This is due to the resultant time delay between the left and right channels resulting in a degradation of phase correlation. This effect is enhanced in an 8-track system, as compared to either reel-to-reel or cassette, due to the larger physical distance, on the tape, between the left and right channel tracks. Resetting head height and azimuth is a primary service procedure required, when refurbishing any vintage tape deck. Once set the player will perform accurately. This format, unlike other tape formats, features a movable head with four positions. Among audio service technicians, there used to be a joke that "the eight-track is the only audio device which knocks itself out of alignment four times during each album." When tracking/azimuth is set using a high quality (ex: Columbia) or alignment tape, correct operation will be restored. Some brands of 8-track decks had adjustable tape head thumbwheel knobs on the front panel, so the listener could adjust the tracking, much like a VHS or Beta tape was adjusted for picture quality. The listener could then adjust the tape head individually for each tape, avoiding double tracking.
The sensing foil that would allow the tape to switch programs, could dry up, fall off, and the tape would separate, and disappear inside the sealed cartridge. This was especially prevalent on bootleg tapes, that used cheaper sensing foils. Had the tape been reinforced on both sides at this point, the tapes would be much more reliable. Many modern collectors replace the old sensing foil with a more robust, properly reinforced foil. As of 2014, rolls of new sensing foil and new pressure pads sell at a steady pace on eBay and other specialty online sites who cater to the format.
The movement of the head at program switch point could sometimes pull the tape up or down, causing the tape to fold over and start playing the back side of the tape. The tape would continue to play, albeit muffled and barely audible. Continued playing would flip the entire tape over, so the tape would be wound on the reel inside with the backside showing. Many vintage tapes can be found with the back side of the tape, facing forward. The program switch point is often the place where the tapes would be ingested into the player i.e. "eaten", when the tape head moved from program 4, to program 1- its furthest track change movement. While moving upward the head would grab the tape, fold it over, and when this fold hit the capstan, it would wrap around the capstan and ingest the tape into the player.
The "melted" rubber pinch rollers that can be found in many early 8-Track cartridges were the result of the rubber not being fully cured. After discovering this cause, later cartridges used only fully cured (hard) rubber pinch rollers that did not deteriorate as much over time.
Tape tension was another cause of unreliability. Prerecorded eight-track tapes tended to hold only a single album, about 46 minutes of content, or 11.5 minutes per track. Consumers wanted the ability to record more music on a single cartridge, so manufacturers came out with units of greater capacity, i.e. 60 and 90 minutes tapes. A few 100 minutes tapes do exist. With the corresponding increase in tape length, there was a greater velocity differential between the tape being drawn from the center of the reel and the tape being fed back to the outer edge of the reel as it passed the capstan/pinch-roller assembly (loop length). A 90-minute tape also exerts more drag on the tape deck motor, making a large AC 120 volt motor imperative to play the longest tapes. Over time, cheaper tapes may tighten, making it more difficult to feed, and to maintain a constant playback speed. Once a tape sheds most of its graphite backing, it will bind up and the tape won't play.
When the sliding tape pack would pull itself tight, for whatever reason, a jammed 8-track cartridge was the result. A quick solution was to hold the cartridge in one hand, facing down, while pulling out a section of, about 4-6' in length from the outer winding side. A quick tug on the tape would cause it to immediately wind in and the result was a loosened up tape pack that would play correctly.
Failing that, another solution was to open the cartridge, cut the tape at the splice, and relieve the excess tension by manually unwinding one or two sections from the outer edge of tape (loop length) while keeping the reel stationary, then re-splicing the tape, with a fresh piece of foil. Another, simpler fix was to shake the cassette in the plane of the tape reel with a rotary motion, sometimes this would cause the windings inside to rotate and loosen. If the cartridge has shed its graphite backing, it would have to be discarded. Small businesses that specialize in transferring audio tapes to digital format can remove the tape from the cartridge and play it on a small reel-to-reel player to extract maximum fidelity.
A decrease in the quality of the parts used in the eight-track cartridge, that is, plastic pinch rollers, lubricant quality and quantity, etc., was another blow to the faltering format. As these problems further reduced the reliability, sound quality, and consistent tape speed, the eight-track eventually developed a reputation for being unreliable.
The Stereo 8 introduced the problem of dividing up the programming intended for a two-sided LP record into four programs. Often this resulted in songs being split into two parts (the split was often made during an instrumental break or a repeated chorus), song orders being reshuffled, shorter songs being repeated, and songs separated by long passages of silence. Some eight-tracks included extra musical content to fill in time such as a piano solo on Lou Reed's Berlin, extra verses on The Rolling Stones' Some Girls and a guitar solo in Pink Floyd's Animals.
In rare instances, an eight-track was able to be arranged exactly like the record album version, without any song breaks. Examples of this are Quadrophenia by The Who, and some versions of Days of Future Passed by The Moody Blues. Other examples of this rarity are Freeways by Bachman-Turner Overdrive, Live Bullet and Nine Tonight by Bob Seger and the Silver Bullet Band, Caught Live + 5 by The Moody Blues, The Concert in Central Park by Simon & Garfunkel, Layla and Other Assorted Love Songs by Derek and The Dominoes, Octave by The Moody Blues, the US version of Three Sides Live by Genesis and Coda by Led Zeppelin (a record club only release).
There are numerous reasons for the format's decline.
Some of the inherent deficiencies of the format were:High wow and flutter due to the constantly changing load presented by the sliding tape pack
Tendency to jam as the tape got dirty, the lubricant wore away, and the tape was exposed to heat
Flattening of the pinch roller, over time, when a cartridge was left plugged in, causing increased wow and flutter
Inability to attain and maintain head alignment due to the movable head design
Rewind is impossible
Consumer units with both play and recording function were rare and expensive
The order of the songs was often changed, and program changes sometimes occurred in the middle of songs (because the album had to be split into 4 programs, the tape length had to be that of the longest program, and any inequality in program length caused blanks that had to be fast-forwarded through)
As time went on, these issues were compounded as later cartridges started using cheaper, lower quality materials, such as plastic pinch rollers. Another contributing factor was an effort by record companies to reduce the number of formats offered. In the late 1970s, when sales of eight-tracks slipped, they were quick to abandon the format.
While the cassette offered features that the eight-track lacked, such as smaller size, greater reliability and both rewinding and home recording capability, it also had disadvantages:Its tape speed was half that of Stereo 8, producing theoretically lower sound quality
The tape needed turning over after one side of playing was finished (until late in the lifecycle of the compact cassette, when 'auto-reverse' mechanisms became more popular)
It required greater mechanical complexity of the player
However, constant development of the cassette turned it into a widespread high-fidelity medium and also lowered the cost and complexity. That, combined with the inherent deficiencies of the Stereo 8 format, contributed to its decline.