Analog Tape Recorders – An In Depth Look at their History and Evolution

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Here we will take an in depth look at the history and subsequent development of the device known as the “tape recorder”, starting with its analog roots and moving beyond into the realm of digital. 

Tape recorders, in some ways, have gone out of style, and yet they still persist into the 21st century for their practical uses, simplicity of use, as well as their aesthetic not to mention economically advantageous charms for both consumer and prosumer alike.

This is why they remain an essential part of how we capture sound for archival, and also entertainment, purposes – to this very day!

Old tape recorder

According to Wikipedia, the “Magnetophon” was noted as the first fully functional reel to reel magnetic tape recorder – was originally a trademark registered by AEG in 1930, based on an invention by German engineer Fritz Pfleumer. 

That said, while this may be true, tape recording technology definitely pre-dates Pleumer’s invention by many decades, a journey which we’ll be exploring presently.

Table of Contents:

  • The First Analog Sound Recordings
  • de Martinville’s Phonoautograph
  • Charles Cros’s Paleophone (“Voice of the Past”)
  • Edison’s Phonograph
  • Oberlin Smith and the invention of Magnetic Tape Recorders
  • Valdemar Poulsen’s Telegraphone (Patent Application #661,619)
  • Pfleumer’s Magnetophon
  • Development of Magnetic Tape Recorders
  • Tape Recorders and the Nazis
  • First Classical Concerts Recorded
  • Reaching the General Public
  • History of the VCR
  • Nagra Portable Crank Handle
  • How a Cassette Tape Recorder Works
  • Reel Diameter
  • Adjusting the Magnetic Heads
  • Connection Sockets
  • Record Setting
  • Removing Clocks & Snoring
  • Recording and Playback Times
  • Monophonic or Stereophonic
  • Advantages and Disadvantages of Long Durations
  • Professional Tape Recorders
  • Comparison of Cassettes
  • Maintenance of Magnetic Heads
  • Analog Tape Conservation, Transfer, and Archiving
  • Tape Recording Tricks
  • Superposition in Re-recording Multiplay
  • Echo and Reverb
  • Main Manufacturers
  • Portable Mobile Recording – Nagra Portable Recorder
  • Uher
  • Misc. Manufacturers
  • Evolution Summary
  • Switching from Analog to Digital
  • The Digital Tape Recorder (DAT)
  • Computer Data

The First Analog Sound Recordings

To understand the origins of analog sound, we must first understand what exactly is an analog signal.

In essence, an analog signal doesn’t need to be sound per sé.  It can be any measurable expression of energy, in a variety of forms. 

analog signal

An analog signal is a continuous signal in constant flux which is expressed through a device of some kind, such as a thermostat (temperature), scale (weight), speedometer (speed), or tape recorder (sound signal).  


de Martinville’s Phonoautograph

There are countless analog devices that have appeared through the past several centuries, but in terms of recording devices, the first such device was technically Édouard-Léon Scott de Martinville’s “phonoautograph”, dating back to 1860.

Édouard-Léon Scott de Martinville

The first recorded sounds, called phonoautograms (after the device), were done by de Martinville himself, singing the French folk song, “Au Clair de la Lune”, and have made their way to Youtube, so you can hear them below.

It is worth noting that while the phonoautograph did technically record sound, it was never meant to play it back. 

The device was created more as a replica of the human ear, where the results of the recording were meant to help visualize sound, in terms of being able to compare the sizes and shapes of waveforms and study musical pitch.


Charles Cros – Paleophone (“Voice of the Past”)

For the first playable groove, we can look to the French poet and inventor Charles Cros, who envisioned a way to play back airborne soundwaves, based on the concepts introduced by the phonoautograph.

charles cros

In 1877, he described the process of playing back sound that he conceived of, thusly to the Academy of Sciences in Paris (translated from French): “A lightweight armature is fixed to the center of the face of a vibrating membrane; it ends with a sharp point, which rests on a lamp-blacked surface.” 

Sound familiar?  This could very well be the idea for the first record, but Charles was picturing more of a cylindrical shape, and suggesting in his letter various ways of inscribing the vibrations of sound onto a surface with a durable but fine-tipped object.

Now, before Charles Cros could create a working model of his Paleophone, the first Phonograph arrived on the scene, courtesy of one Thomas Edison…


Edison’s Phonograph

Edison_and_phonograph_edit1

This device was the first to feature audio recording playback, and it was a “hit”.

But what exactly is a phonograph?  The phonograph was a mechanical device also called a gramophone, invented and trademarked by Edison in 1887 that was able to record sound, and also reproduce it, via a record. 

But first, airborne sound waves needed to go into a horn-shaped receiver, in order to be captured via the recorder.  You may recognize this famous picture below.

Frances_Densmore_recording_Mountain_Chief2

More on the process: “Sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc”. (Wikipedia’s Phonograph entry).

Here is a phonograph in action below…


Oberlin Smith and the invention of magnetic tape recorders

Oberlin Smith

Enter Oberlin Smith, New Jersey machinist.

After meeting Edison at the Centennial World’s Expo in Philadelphia, 1876, Smith and Edison became acquainted and Smith managed to get his hands on an actual phonograph, which Edison gave to him, in April of 1878, which Smith then began using, as one would.

Around September of 1878, Smith came up with ideas for potential improvements to the phonograph, which involved magnetic tape.

According to oberlinsmith.org, Smith “outlines the possibility of magnetic sound recording on a magnetizable medium of tempered steel which is magnetized by a short helix. Playback by means of induction. Advantages: cheap, simple, “delicacy”.”

Oberlin-Smith-1

These improvements were submitted to the Cumberland County Clerk by Smith, and marked the invention of magnetic tape recording as an idea, if not yet fully applied.  

Oberlin Smith also submitted some of his ideas to a magazine called The Electrical World, which saw some of his ideas published in 1888, September, as “Some Possible Forms of Phonograph”.  Here below is a copy of The Electrical World from 1887.

1887-march-electrical-world-magazine_1_830c6c8ea787f6a5f2b00ddc10801d88

Despite his ideas being published in The Electrical World as a reader letter where he explains “the elongatedly drawn coil as an error in illustration and refers to his experiments with a single-pole transducer”, and despite ordering several buttons of “mercury-impregnated carbon” from Edison, Oberlin Smith would not be the man to first actually patent or build an actual magnetic tape recorder.


Valdemar Poulsen’s Telegraphone (Patent Application #661,619)

The first successful filing of patents for the first magnetic tape recording was by Danish engineer Valdemar Poulsen (pictured below) in 1898, who created what would be called the Telegraphone (Patent Application #661,619), the first functional magnetic tape recorder.

This device was then debuted at the 1900 World Fair in Paris, where he recorded the voice of Emperor Franz Josef of Austria, astounding the crowd there.

valdemar poulsen

For years, Oberlin Smith challenged Poulsen’s patents, apparently having met him some time earlier, and not receiving credit from Poulsen, to which he got no response.

Eventually, however, Smith was credited by Emile Berliner at the Franklin Institute in Philadelphia as being the first to propose the idea of magnetic tape recording, and publicly brings into question whether Poulsen was dependent on Smith’s ideas, or not. 

Dying in 1926, Smith is credited with the Autofono, an automatic record changer, just weeks before his death.


Pfleumer’s Magnetophon

A collaboration between AEG Berlin an BASF Ludwigshafen, along with the ingenuity of Fritz Pfleumer, sees the emergence of the “Magnetophon” at the Berlin Radio Exhibition, in 1935, which is a huge success and it is at this point where tape recorders, as well as recordings, begin to find their foothold in global recording culture. 

Fritz_Pfleumer tape recorder

Plfeumer, for his part in this story, is the man who was able to bind powder to tape, upon request of BASF, while he was developing a cigarette filter.

This resulted in what is considered the first truly practical tape recorder, although the sound quality was still rather grainy.


Development of Tape Recorders

AEG then embarked on an extensive program of research and development on magnetic heads, tape transport mechanisms, and amplifiers to perfect their new model for the tape recorder.

At the same time, work on the magnetic strips were carried out at the IG Farben plants in Ludwigshafen (now BASF).  The collaboration we mentioned in the last section was beginning to take shape.

At the beginning, the strips were not extremely durable. They are 5 mm wide and run at 1 m / s. The quality, at this point in time, was still mediocre and breakage was common.

In 1932, AEG expanded the band to 6.5 mm and decided to work on a new, stronger support: the first acetate bands were born in 1934.

They were, at this time, covered with carbonyl (carbonyl iron). Still, the size of the particles did not allow for high quality recordings, and the DC pre-magnetization made the medium very linear.

The few musical recordings from this era are of a disastrous quality.  That said, things were on the up and up.

AEG_paper_tape_recorder_1920-30s_212

IG Farben perfected the band in 1936 by replacing the carbonyl with iron oxide Fe3O4 which was black in color.

The scrolling speed is then reduced to 77 cm / s (which the Americans will round off in 1945 at 30 inches per second, or 76.2 cm / s). It was not until 1939 that the brown iron oxide Fe 2 O 3 was used for better sound quality.

High fidelity was only possible in 1941 with the use of high-frequency pre-magnetization (although discovered in the 1920s, it will remain ignored until a recorder produces records of unsurpassed quality: pre-magnetization with direct current had oscillated).


Tape Recorders and the Nazis

hitler

Adolf Hitler and his party go on to make extensive use of the tape recorder for their radio speeches: public speeches like those of the Reichstag were systematically recorded.

Other speeches were pre-recorded and broadcast from studios after Hitler had left the premises, allowing for the proliferation of Nazi propaganda all over Europe.

The quality of the amplitude-modulated radios of the time (4,500 Hz bandwidth) rendered the sound of the tape recorder indistinguishable from that of him speaking directly.

These events just go to show that technology, when it falls into amoral hands, will of course be used for such deeds.  Once the technology exists, the cat is officially out of the bag, as they say.  Anyone can use it – even a misguided and malevolent dictator.


First Classical Concerts Recorded

early classical recordings

As early as 1939, AEG worked on a head with two air gaps to record two tracks on the same band.

Initially, it is only to capable of recording the same signal in push-pull fashion, but this method does not succeed.

The first stereophonic recordings were made in 1942. Most of the concerts were recorded as early as 1941, of which more than 250 were recorded in stereo.

In 1945, the Russians seized about 50,000 bands of all kinds, of which only a little more than a thousand were returned to Germany in 1991.

Among them, there are a number of public concerts directed by Furtwängler, Karajan, Knapertsbuch, and more than 600 bands of lieder (Schubert, Schumann, Mahler) with Michael Raucheisen on piano. 

Here is a very early Beethoven recording, where the quality is surprisingly high.


Tape Recorders Reach The General Public

Tape recording became widespread as early as 1946 in America where Bing Crosby made his shows on tape before pressing them to disc.

Ampex will dominate the market for several decades.

The first tape recorder sold to the public in 1947 is the Brush’s Soundmirror BK-401, which also produces its own tapes, initially made of paper and then made of plastic.

Soundmirror BK-401

Scotch launched in tape in 1948 with tape Type 100 (paper) followed by 101 (plastic).


History of the VCR

As early as 1950, the Americans worked on a method of recording the television image on tape. The VERA system is functional, but too greedy in terms of the amount tape needed.

It is Ampex who will produce the first video tape recorder 2 inches (quadruplex system). The machine will be functional as early as 1956 and will even work in color as early as 1957.

AMPEX_VRX-1000_3

The phonographic industry will also use the tape recorder to replace the wax patches that did not allow for any editing.

The companies Deutsch Grammophon and Telefunken will be the first to use the AEG tape recorders to record their 78-turn discs (and later microphones).

France will start using tape recorders for radio in 1948 and tape recorders will begin to attract audiences in the early 1950’s.


Nagra Portable Crank Handle

In 1951, the Nagra I (miniature lamps and crank winding) was the first very small (1/4 inch) magnetic tape recorder (30 x 18 x 10 cm) and revolutionized the recording of radio reportage.

1_Nagra-1

The Nagra climbs to the highest level (above sea level, that is), accompanying an expedition on Everest and sinks into the depths along with the bathyscaphe of Professor Piccard.

In the early years, amateurs used their tape recorder more to record their family affairs than to record a record or radio (what the novices did sometimes by microphone in front of the loudspeaker with very little sound fidelity, lamps with few connection sockets to a tape recorder).


How A Cassette Tape Recorder Works

A cassette tape recorder had a central device in which the tape was made to pass from the transmitting coil, consisting of a left-hand guide, a head for erasing any previous recordings, a head a recording head, a recording head (or a single recording / playback head), a driving assembly carried out by the capstan on one side, a rubber roller performing the pressure on the other, and a straight guide, before joining the take-up spool.

panasonic rq2101

Each of the two spools was held by a small central spindle with 3 triangular spikes, arranged on a small circular horizontal support plate (unlike a 78-spindle or micro-spindle disk, the central cylindrical spigot and simple adhesion and weight (except soft discs) on the non-smooth surface of the tray was sufficient) to ensure rotation of the take-up spool, the speed of the belt being controlled by that of the capstan, as well as that of the transmitter and receiver for fast winding or rewinding.

tape recorder mechanism

In order to pass the magnetic side of the strip on the side of the heads, and not the other way round, the strips being brown on both sides (color of iron oxide) and then dark brown in the 1970’s, of spotting was the frosted aspect on the magnetism side, and shining on the other side.

In order to maintain sufficient band tension on the left and right transmitting and receiving coils, a motor drives the take-up spool forcefully at a slightly higher speed than the maximum rotational speed, as well as the slightly revolving transmitter.


Reel Diameter

The coils were plastic or metal, and similar to movie projectors 8mm.

The most common diameters were 8 cm (dictaphones and portable mobile equipment), 13 cm (mobile portable equipment), 15  cm and 18  cm (domestic equipment) and 27.5 cm (professional equipment). The typical length of a 13 cm diameter coil was 1 hour .

The amateur recorders were placed horizontally, initially with 13 cm reels, then up to 18 cm from the 1960s, and often vertically from the 1980s, with 26 cm reels, which were much easier to handle.

The first devices were tube, monophonic twice a track, then stereophonic, and gradually “transistorized” on integrated circuit boards.


Adjusting the Magnetic Heads

The positioning of the heads was adjusted and calibrated at the factory so as to be perfectly rectilinear, but it was often the case on the amateur recorders that there was an angular offset between the original recording and the reading giving an “oblique” signal and especially a phase shift between the two stereo signals.

This gave some clipping and distortion, especially if they were subsequently monophonized, appearing first by a loss of treble (but which could be compensated by a tuning screw, which was adjusted to the ear on the sharpness of the treble).


Connection Sockets

The tape and cassette tape recorders had a number of shielded cable connectors (sold in shops, but also in kit that can be welded by the operator):

A microphone plug, 2-pin DIN (signal + ground), then 3-pin (dual stereo microphone), then large format jack since the 1980’s.

tape recorder connector sockets

A connection socket to a HIFI or other compatible device, input / output (recording or playback), DIN 3-pin mono then DIN 5-pin stereo, then 4 American RCA since the 1980’s. A listening jack for control over headphones, large format jack or small format.

The transition from DIN to RCA in the 1980’s introduces a difference in impedance compatibility, with the recording becoming weaker, and an upgrading of the devices was required by the operator.


Record Setting

The recording volume was adjusted by a button, then for some tape recorders a slider or rotary potentiometer, associated with a control galvanometer called “vu-meter”:

Recorded above a certain volume, the magnetic oxide particles could no longer deviate further, and saturated. This saturation can also exist on a microphone, the width of the groove being limited, as well as on a CDR or mini-disc.

MITSUBISHI DT-30 3Motor:3Head

Recorded at too low a volume, it required “pushing” the playback volume, which also amplified the band blast.

The first amateur tape recorders indicated the volume recorded on the tape using, until about 1965, as in lamps, a “magic eye”, which retracted more or less, until disappearing completely at saturation with the optimum volume being at the retraction limit).

Both the left and right channels, 2 needle galvanometers, using a green zone, used a yellow “best efficiency zone” (better signal-to-noise ratio) and a red zone indicating the saturation of the recording of the magnetism of the bands.

magnetic tape recording mechanism

Until the 1970’s, only the volume of recording was indicated by the galvanometers, then in the 1980s they also displayed the volume recorded at the time of reading.

A few appliances used “LED” indicators from the 1990s.


Removing Clocks and Snoring

Other improvements include the switching noise known as “clocks”, which is spurious in a fraction of a second, caused by the lighting and extinguishing of the red lights signalling the opening and shutting of the microphones. 

This happened particularly in the studios broadcasting (and on their doorstep the prohibition to enter), very clear on the direct but attenuated by the addition of capacitors, or on the first magnets to reels (and cassettes) until the beginning of the Sixties.

At the start and stop of the recording, audible in reading, by the sudden pressing of the magnetic head and the reaction of the electronic circuits, and then possibly the same sudden stop (unless using the “pause” , rather than “stop”), which the manufacturers succeeded in mitigating, and then disappearing completely over the years on all tape recorders.

The possible slight “snoring” of the sector in the background at 50 Hz, in recording and / or reading, due to the lamps of the tape recorders of the 1950s (as on tube stations) disappeared with transistorization and progress low frequency “filters”.


Recording and Playback Times

From the “standard” thickness of the strips, the quality of the supports made it possible to progressively reduce this thickness, so as to propose, from the 1960s, durations up to 4 times greater than those of origin for the same speed (which was also the case of cassettes, ranging from C30 (2 times 15 min) to C180 (2 times 90 min)).

At a speed of 19 cm / s (7.5 “/ s), called” fast “at the time by the” amateurs “, on a reel of 18 cm , on the total of the two recording directions and in stereophony , the durations (as indicated on the housing boxes) were approximately:

  • Standard time (360 m): 1 hour
  • “Long” duration (540 m): 1 hour 30
  • “Double” duration (720 m): 2 hours
  • “Triple” duration (1080 m): 3 hours
  • “Quadruple” duration (1440 m): 4 hours

The above durations are depending on the scrolling speed.

sound tapes

These times also being inversely proportional to the speed of travel, and proportional to the length of the belt, and therefore to the square of the diameter of the coil (less the approximately proportional diameter of the central hub) , with respect to 19 cm / s (7.5 “/ s) (fast speed) :

  • Multiplied by 2 to 9.5 cm / s (3.75 “/ s) (average speed)
  • Multiplied by 4 to 4.75 cm / s (1.87 “/ s) (slow speed)
  • Divided by 2 to 38 cm / s (15 “/ s) (” Professional “speed)
  • Multiplied by 8 to 2.37 cm / s (0.94 “/ s) (adopted on Uher laptops for conferences)

These speeds are depending on the diameter of the coils.

In the same way, these durations could be compared to a coil of 18 cm:

  • Multiplied by 2 for a 26 cm reel
  • Divided by 1.5 for a 15 cm reel
  • Divided by 2 for a 13 cm reel

Monophonic or Stereophonic

Of course, on 4-track stereo tape recorders (2-way playback), recordings made in single monophony could, by being recorded on each track, multiply by 2 the duration.

The tapes could be returned at the end of recording to ensure a second session (some tape recorders were even self-reversing at the end of tape).

The same bands were used for full track recordings, 2 tracks and 4 tracks , but the recordings were obviously not compatible. One of the tracks recorded on a 2-track recorder was played lower on a 4-track.

SONY TC-U5 Stereo Cassette Deck

Conversely, a 2-track tape recorder playing a 4-track recording gave an inaudible result, consisting of the mix of the two tracks at the location and the other two tracks of the adjacent piece in reverse, unless only 2 of 4 tracks were initially recorded.


Advantages and Disadvantages of Long Durations

Note that when the durations are increased, they have certain advantages:

  • Saving the recording time on the same medium, combined with space saving
  • Obligation to change face or coil less frequent,
  • Reduced rewind time to search for recording at lower speed,
  • Magnetic smearing and less rapid friction wear of heads at low speed

But in return have several disadvantages:

The finer the band, the more fragile it is, increasing the risk of fracture, twisting and tangling, especially during fast winding or rewinding.

broken cassette tape

Below a certain thickness, the reduction of the “deep” bass spectrum (20 to 60 Hz) is required to reduce the magnetic layer a little to manufacture.

Proportionally larger purchase price, as these bands are more difficult to manufacture.

A crying on certain magnets at the end of the band at “fast” speed, due to a “skating” between the capstan and the roller on a band that is too fine polyester, no longer being able to compensate for the inertia of a transmitting coil with a small central hub, almost empty and having to turn all the more quickly.

For slower recording (especially at 4.75 cm / s ):

Loss of fidelity in the sharpest treble (10 to 16 kHz), leaving better place for the blast or “white” noise of the band, due to the “sliding” of the strip between the roller and the end of the capstan.

In case of non-rectilinear azimuthing of the recording / playback head, multiplication by 2 or 4 of the clipping or even the distortion in the treble, from one magneto to the other.


Professional Tape Recorders

It goes without saying that professional tape recorders, especially for recordings recorded on discs or for broadcasting in public concerts, were of optimal quality:

“Full Track” for a monophonic or “2-track” recording for stereo recording, and even using much wider bands to perform the muti-track mounts before switching “Stereo” over the entire width of the band (not returnable, it has given in this case the music or the lyrics backwards …), are, of course “standard” thickness.

TC-D5M-negativland-com

High speed recording: 15 “/ s (38 cm / s), or even 76 cm / sec (30” “/ sec)

“Open” coils on the upper side (not needing to be turned upside down), to minimize possible noise and static friction.

Azimutage perfectly adjusted in phase with 3 separate heads : Recording, reading, erasing.

The quality of the tapes and appliances improved over the years, and a “correct” recording at 9.5 cm / s and mediocre at 4.75 cm / s in the 1960s became almost 9.5 cm / s as good as 19 cm / s and correct at 4.75 cm / s in the 1980s.

Amateur recordings, especially made with “inexpensive” (and without dolby) tapes or cassettes, were accompanied by a slight loss of treble, this loss added to each possible postponement, which was compensated by accentuating the treble to the listening, but also the breath.

Magnetic tapes have historically had two supports:

Acetate: This tape was inexpensive to manufacture, but withstood very poor mechanical stresses (sudden stop, for example), and forced to introduce delicate tape tension control mechanisms into the tape recorders.

The risk of breaking bands remained high if different transmitter and receiver coils were used (due to the different inertia of the coils);

Polyester: More expensive to buy, it had a much better mechanical strength and finished in the 1970s by completely dethroning the acetate, relegated to the establishment of only “disposable” recordings.

maxell SA-X90 super avinlyn high res

In 1985, Maxell produced some 26 cm “chrome” magnetic tapes for a better quality of treble, but much more expensive than iron, and tape recorders with this setting were unlike cassette recorders, which were very rare and not compatible.


Comparison of Cassettes

It should be noted that cassette recorders adopted from the outset the standardized speed of 4.75 cm / s , using, moreover, bands about twice as narrow and twice as fine, and, therefore, even less theoretically faithful in quality, to succeed to be incorporated in these “mini-boxes”

That said, the technique had already progressed since, and continued to progress with the improvement of the acute by the strips called “Chrome” then “Metal”, and the reduction of the breath by the “Dolby” systems B, C then S.

Some larger cassettes were also manufactured for a few years, with the width and thickness of a band of coils and a speed of 9.5 cm / s for better sound fidelity (speed also used for convenience on some magneto- cassettes).

The “standard” cassette format, which is more practical, less cumbersome and has more recording capacity, has been constantly improving and has therefore become too busy for too many years commercially so that these cassettes are sufficiently interesting, moreover, they were in quality and duration, that the equivalent, more practical of use, but more bulky, of a reel of 8 cm.

TDK_D_C180_cassette

The “quadruple durations” (as well as the C180 cassettes), which were too fragile, were only manufactured for a few years, and even triple durations (as well as C120 cassettes) were not recommended unless necessary for broadcasting purposes. example.


Maintenance of Magnetic Heads

The magnetic tapes always wear a little bit when passing the heads, depositing a thin layer of oxide on them, requiring regular periodic cleaning of the heads with a cloth or cotton swab impregnated with alcohol or a suitable solvent harmless, failing which the oxide was a screen leading to a progressive loss of acute.

It was sometimes necessary to also clean the main mechanical parts such as the capstan and the roller which could also be covered with oxide disturbing the speed.

Another small common defect is a sharp “grinding” caused by the rubbing of the old bands coming in “resonance” on the metallic guides, the latter appearing less on plastic guides of the cassettes, some of which cheap sometimes creaked at the winding.

When the heads were somewhat shifted in “depth” adjustment, or even the band deformed slightly over time, this slight offset could occur when listening between tracks, with the overflowing rear center track being added as a “Fading” where you could hear the basses slightly upside down superimposed on the desired tracks which they became a little weaker when listening.

Over time, old or even reused tapes, even if stored in good conditions of temperature and hygrometry, and protected from light, have become brittle, the oxide ending in decreasing, becoming sticky when winding to the next (even polluting and poison), sometimes resulting in an irregular volume of sound, then a permanent loss of the treble.


Analog Tape Conservation, Transfer, and Archiving

The INA, anxious to preserve valuable archives testifying to the preceding epochs, preserved for this reason (as it did for films, especially those called “flame” in celluloid!), by transferring them to more and more modern supports.

Reprints on CD of old recordings since the 1950s take back where possible the bands of origin (if not more and more, the microphones), by remastering them, fortunately these professional bands were originally an excellent quality, then carefully preserved.

storing magnetic tapes

As early as the 1960s, the strips were preceded and followed at each end by a frosted plastic stripe of about 60 cm (often green and red to identify the faces without inverting them), followed by a small band bonded to this leader tape preceding the magnetic tape.

Besides the advantage of being thicker to insert it in the receiver coil, it allowed to start the first piece and to finish the last one more precisely.

The tape recorders were then equipped with an automatic “stop” device, which, when passing through the metal band, stopped the assembly, avoiding that once the tape was completely terminated, the take-up reel and possibly the transmitting reel to rotate in a vacuum at high speed, which frequently happened before in the event of the operator not being monitored.

As with cassettes, when there was no longer enough tape on the transmitter coil to record a final new song, the operator would either let it cut “net” or “shunted progressively to” fading decrescendo “Or prefer to leave a” blank ” if he did not want a cut piece (the” cleanest “choice). Subsequently, the auto-reverse allowed the continuation of the entire piece, but with a mini-cut of a fraction of a second.

cutting magnetic tape

Mounting kits, with 2 rolls of green and red leader strips, a roll of metal strip, a roll of adhesive tape, a plastic guide and a cutter were sold frequently for amateurs.

It was common to perform entirely “manual” assemblies (similar to those performed for film films), by “marking” a mark on the bold pencil strip at the precise location of the connection, ( the support being clearly thinner and more flexible than a film film which used a special heat-dried adhesive ), is carried out by means of a longitudinal adhesive of 4 cm approximately.

This bonding was of course also used in the event of breakage of the strip, frequent on those in “acetate”, breaking much more easily, especially over time with heat.

On the other hand, editing has become practically impossible on the cassettes, too thin and small, editing by “carry” recording with very little loss of quality becoming preferable from the 1980’s.

The dissociation of the 2 tracks (4 with each side of tape) in separate mono, and so the Multiplay process, although feasible, did not exist on cassette tape recorders either.

All these assemblies have become extremely easy in recent years, with the emergence of digital and computing, by means of the most complete and practical editing software, many of which are accessible to amateurs.


Tape Recording Tricks

Tracking high-speed tracks – It was common to spot a sequence or piece of music at high speed on the tape recorders remaining in playback (certainly very sharp) when rewinding front or back (this option was also offered in the “Cue” mode on cassette tape recorders ) .

Octave higher than double speed – It was also possible to “juggle” with the speeds, a recording performed at double speed taking a double frequency, thus located musically one octave above, and vice versa at half speed, thus allowing certain “tricks” in the sounds of a ” (which was also possible by changing the speeds of record players, but these did not have this ratio of “2”, except between 33 t 1/3 and 16 t 2/3 (1 octave), and close to 4/3 between 45 t and 33 t 1/3 (1 quarte) 6 ).

Many amateurs thus enjoyed themselves talking or singing in the family, having as a quick voice a “mouse” at double speed, or slow “bear” at half speed.

Repetitive announcements (made today by computer or CD) could also be done mechanically by running a very short loop around the reading set (special cassettes of this type were also made).


Superposition in “Re-recording Multiplay”

The “Multiplay” technique, available on some “modern” tape recorders on the Grundig tape recorder since 1967, also allowed: to record in mono with an instrument or a voice on track 1, then to carry it on track 2 by adding an instrument, then do the same with another instrument or voice on track 1, and so on, up to the equivalent of a major orchestra or choir performed by only one or a few people (which is also currently available on synthesizers).


Echo and Reverb

In the 1980’s, if the reading head was “downstream” of the recording head, the almost simultaneous reading (known as “Cue”) was possible during recording, allowing the result to be verified directly.

The “Echo / Reverb” mode was added, with a greater or lesser offset depending on the distance between the 2 recording and playback heads and the speed.

pathe

Some reissues of old monophonic recordings, even 78 laps, as in Pathé, used this method in the 1970’s, thus recreating a relief of “false stereo”, but this one too artificial and degrading a little the sound “Natural”, a real good “mono” was re-adopted later.


Main Manufacturers

In the 1950s, many individuals and teachers discovered the thousand and one possibilities of magnetic recorders:

Specific in the pedagogical use of language learning, dictation, dance and music, private amateur, to record radio, records, family or sound editing their slides or amateur movies.

The market is then dominated by the following brands:

  • Netherlands: Philips (which also manufactures tape recorders in France and Austria);
  • Japan: the inescapable Sony , but also Akai and TEAC . The fleeting appearance of Dokorder in the 1970’s. More discreet manufacturers like Crown, Nivico (JVC), National are trying to establish themselves in the portable recorder market;
  • Belgium: Acec, which launched Sonofil in the 1940s, launches the Lugavox range and the very original Carad R62, R53, R66 and R59 series;
  • Norway: In 1970, Tandberg Audio, also a specialist in language laboratories, took over the cross-headed heads device, which contributed to the renown of Akai, recording synchronization beeps by a polarized ultrasonic signal in a magnetic head slightly offset from the recording head;
  • Switzerland: Studer ( Revox ), Stellavox, Nagra  ;
  • West Germany: Braun , SABA , Saja (Sander & Janzen), Maihak, Grundig , Telefunken , AEG , Uher
  • Germany (East): VEB Messgerätewerk Zwönitz;
  • Czechoslovakia: Tesla;
  • Poland: Unitra.

Portable Mobile Recording – Nagra Portable Recorder

Invented by Stephan Kudelski, Polish-Swiss of about twenty years, it quickly becomes synonymous with portable tape recorder for all professionals of the information. The Nagra mark comes from the Polish word, which means “it will record”.

Robust and quality-minded, Nagra will be the basic tool for journalists and the majority of film sound engineers.

Nagra_LINO_Professional_Handheld_901495

It will also be the machine of choice of explorers of extreme and instrumentation embarked, in particular for aeronautical research.

The Nagra are standardized to the standards of the studio machines and have many modules and accessories for specific needs, such as special inputs or cinema synchronization devices.


Uher

In the 4000, 4200 and 4400 series, without looking for the robustness of the Nagra, these 13 cm reels were very popular among amateurs. A Uher 4200 tape recorder is shown at the beginning of James Bond’s Thunderball movie .

thunderball uher 4000

The CR124 will be the first cassette recorder standards HiFi DIN 45500 at the time. His successor, the CR210, will accept chrome cassettes.


Miscellaneous Manufacturers

  • Stellavox  (en)  : Swiss manufacturer, specially oriented to the film industry.
  • Nakamichi  (in)  : Japanese manufacturer.
  • Studio recording [ edit | change the code ]
  • France: Tolana, Bourdereau, Schlumberger / Digitec
  • Germany: Telefunken / AEG
  • Switzerland: Studer / Revox
  • Japan: Sony , Otari , Fostex , Tascam
  • US: 3M , Ampex , MCI  (in) , Scully, Soundcraft
  • Great Britain: Ferrograph, Brenell, Leevers-Rich

Evolution of Cassette Tape Players

In 1963 , the cassette launched by Philips more convenient to handle, will gradually replace the strips in the coils during the 1970’s, although the tape parallel magnetos continued throughout the time of the magneto-cassettes, as always remaining higher technically in quality, especially for professionals.

This miniaturization due to the cassettes with respect to the reels will allow to develop new devices of all sizes ranging from the compact walkman to sophisticated cassette recorders with 3 motors and 3 heads. Larger, the DC system supported by Grundig and Telefunken, will not impose itself despite its sound quality at the top start.

During the 1970s and 1980s, the Philips cassette became able to reproduce recordings of high fidelity, thanks to the appearance of bands with magnetic properties superior to iron, such as chromium in 1973, then metal in 1979; of the bottom pink noise reducers of the band, mainly the Dolby B in 1968, then Dolby C in 1980, the Dolby HX Pro in 1982 and Dolby SR in 1986.

Other types of tapes were quite ephemeral, such as the 8- track car radio cartridge in the United States, 4 x 2 tracks on endless but often jammed, and Sony’s Elcaset faithful, with a strip of 1/4 “to 9,5  cm / s , but arrived too late in 1976 and very expensive.

Elcaset_Deck


Switching from Analog to Digital

The arrival of digital in the 1980’s of greater flexibility, with the compact disc then the internal electronic memory players put the analog tape recorder back, although the listening and recording qualities of it remain superior.

billy joel cd 1982

Indeed, the bandwidth of the analog band can reach 50 000 Hz while the current digital formats are limited to 20 000 Hz.

However, according to Shannon’s theory, the sampling frequency must be at least twice the highest frequency to be sampled.

The end of the 1990s will see flourish ads for cheap sale of high-end Studer Revox tape recorders , their owners discovering that their PC equipped with a good sound card is even more convenient.

The tape recorders were used extensively by sound professionals, the best performers to deal with multiple tracks at the same time, making it possible to modify the sound balance during the mixing phase ), and in general fashion in the 1960s to 1990s for their portability.

Manufacturers have even extrapolated video recorders or video recorders and later camcorders.


The Digital Tape Recorder (DAT)

The tape recorder has also evolved and in the early 1990s it became the Digital Audio Tape (DAT) tape recorder and the ADAT multitrack recorder.

Studio Recordings – The digital tape recorder was used extensively by professionals to record commercial discs from the 1980s on:

The recordings were more and more recorded from digital tape recorders and sometimes engraved at half-speed for better fidelity, especially for classical music, bearing the label “DAA” or “DDA” (Digital- Digital-Analog (the analogue being the engraving on micro-chip)), then

For recording on compact discs , the label indicating on the disc and / or the booklet of the CD:

ADD (Analog-Digital-Digital): use of an analog recorder during recording sessions, then digital for mixing and / or editing and burning, or

DDD (Digital-Digital-Digital, the best of high fidelity): use of a digital tape recorder during recording sessions, mixing and / or editing and burning.


Computer Data

The same principle has been widely used for the recording of computer data by bit and byte, but with very different bands: those used for audio quality had to have as little hysteresis as possible.

Those used for the digital recordings had to have a high hysteresis, in order to differentiate as clearly as possible the states 0 of the states 1, the intermediate values ​​being of no interest.

Replacement by hard disks and then computer memories – Since the generalization, from the years 2000, digital recording on hard disk , then on memory card, SSD ( solid-state drive ) or others, the tape recorder and the recording of digital data on magnetic tape have become obsolete.

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