The 8-track tape (formally Stereo 8; commonly known as the eight-track cartridge, eight-track tape, or simply eight-track) is a magnetic tape sound-recording technology that was popular in the United States from the mid-1960s to the early 1980s, when the Compact Cassette format took over. The format is regarded as an obsolete technology, and was relatively unknown outside the United States, the United Kingdom, Canada, New Zealand, Australia, West Germany, Italy and Japan.
The Stereo 8 Cartridge was created in 1964 by a consortium led by Bill Lear of Lear Jet Corporation, along with Ampex, Ford Motor Company, General Motors, Motorola, and RCA Victor Records (RCA - Radio Corporation of America). It was a further development of the similar Stereo-Pak four-track cartridge introduced by Earl "Madman" Muntz (marketing and television set dealer), which was adapted by Muntz from the Fidelipac cartridge developed by George Eash. A later quadraphonic (four-channel sound as opposed to earlier more widely used stereo/two channel sound) cartridge version of the format was announced by RCA in April 1970 and first known as Quad-8, then later changed to just Q8.
The original format for magnetic tape sound reproduction was the reel-to-reel tape recorder, first available in the United States 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 more quickly 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 Tape 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 (9.53 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 1963.)
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, marketer and television set dealer 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 (two channel) sound 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 slippage. 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, the Ford Motor Company introduced factory-installed and dealer-installed eight-track tape players as an option on three of its 1966 models (the sporty Mustang, luxurious Thunderbird, and high-end Lincoln), and RCA Victor introduced 175 Stereo-8 Cartridges from its RCA Victor and RCA Camden labels of recording artists 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 U.S. automakers, the eight-track format quickly won out over the four-track format, with Muntz abandoning it completely by late 1970.
The 8-track format gained steadily in 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 helped generate demand for home units. "Boombox" type portable players were also popular but eight-track player/recorders failed to gain wide popularity and few manufacturers offered them except for manufacturer Tandy Corporation (for its Radio Shack electronics stores). With the availability of cartridge systems for the home, consumers started thinking of eight-tracks as a viable alternative to 33 rpm album style vinyl records, not only as a convenience for the car. Also by the late 1960s, prerecorded releases on the 8-track tape format began to arrive within a month of the vinyl release. The 8-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 Great Britain and worldwide. 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 to promote 8-track product and musicassettes in Britain and Europe, but it struggled and folded in 1974. GRT Corporation, General Recorded Tape of Sunnyvale, California, was another large manufacturer which duplicated many tapes for smaller record labels; it went out of business in 1979.
Quadraphonic sound on eight-track cartridges was announced by RCA in April 1970. It employed four-channel receiver/amplifiers that balanced the sound via sliders or a joystick.
Ford was particularly eager to promote in-car quadraphonic players as a pricey option, being the only "Big Four" American automotive company to do so. The format enjoyed moderate success in the early 1970s but faded by mid-decade. Quadraphonic cartridges provided four channels of discrete sound, unlike matrixed formats such as SQ, which Columbia/CBS Records used for their quadraphonic sound vinyl records.
An 8-track cartridge provides four pairs of stereo tracks, whereas the later quadraphonic cartridges had two sets of four tracks. The ends of the tape were spliced with a thin strip of metal that would trigger a solenoid that would cause the playback heads to automatically jump to the next set of channels. Both types of players also provided a button for manually changing channels. Due to the design of the endless loop tape, which fed from the reel in only one direction, there was no rewind control. Due to the mechanical stress on the tape, few machines offered a fast-forward control.
The mixing process for producing quadraphonic media varied between titles. As was the case with many early stereo recordings, some producers opted for a hard separation between channels, such as an individual instrument or vocal being assigned to only one track of the four, while other producers chose to mix in content from the other channels to create more of a balance. A few producers created mixes in which the four output channels would pan in sequence through the four source channels to create a rotating sensation. The rarely-heard effect was spectacular, but as there was no technology to produce this automatically, it would require two mixing engineers who, with practice, could coordinate their efforts to create the effect. Due to this challenge, few songs were created with this effect.
Milton Bradley's (MB) OMNI Entertainment System was an electronic quiz machine game first released in 1980, similar to Jeopardy! or later You Don't Know Jack video game series, using 8-track tapes for playback analog audio for questions, instructions and answers as well as digital signals in magnetic tape data storage on remaining tracks to load the right answer for counting the score. In 1978, the Mego Corporation launched the 2-XL toy robot, which was similar.
Eight-track players became less common in homes and vehicles in the late 1970s. The compact cassette arrived in 1962, and by the late 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 smaller cassette tape which was one-third the size.
In the U.S., 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. M Radio Shack (Tandy Corporation) continued to sell blank eight-track cartridges for home recording use under its Realistic brand until 1990.
The professional broadcast cart format survived for more than another decade for jingles, advertisements, station identifications, and limited music content at most local radio stations, before being replaced by computer-generated sound in the 1990s. It persisted for relatively short sound loops where starting from the beginning was more important than other criteria. The endless loop tape concept continued to be used in newer movie projectors, though their tape spool is actively rotated and not drawn by tension on the film. That technology is now being supplanted by digital cinema.
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.
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 matchbook-under-the-tape fix was done primarily because the worn capstan 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 the later Beta and VHS video tapes that were 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 have been 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 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 surrounding plastic cartridge box and play it on a small reel-to-reel player to extract maximum sound 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 - Bursting Out by Jethro Tull, 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, Pictures at Eleven by Robert Plant and Coda by Led Zeppelin (a record club only release).