Previously on the Story of Sound blog series, we travelled back in time to discover the first invention to record and re-play audio, uncovered forgotten formats such as the wax cylinder, and learnt how American President Franklin Roosevelt is linked to the success of vinyl discs:
2: “Canned music” and a war of formats
3: Shellac to vinyl, how World War Two changed the record
In 1963 in Berlin, Germany, a new audio format was released that revolutionised the music industry. The compact cassette tape, developed by the electronics company Philips the previous year, was unlike any previous audio format. At a time when music was bought on vinyl discs at a cumbersome 7, 10, or 12 inches in diameter, the arrival of a small portable format that could be carried in a pocket or played in a car introduced a new era of commercial sound.
While compact cassette tapes may be remembered in association with Walkmans, recording songs from the radio, or sending mix tapes to sweethearts, the magnetic audio tape inside has a long and important history; from transforming the BBC’s broadcasting abilities, to being a closely guarded secret of the Second World War.

Magnetic audio tape stems all the way back to the 19th century, when in 1898 the Danish inventor Valdemar Poulsen created the first magnetic recording device, the Telegraphone. Unlike the audio tape we know today, the Telegraphone used magnetised wire, and at the 1900 World’s Fair Poulsen used the device the capture the voice of Emperor Franz Josef of Austria, now the world’s oldest magnetic sound recording.
In 1932 the BBC launched the Empire Service [now the World Service], which required them to broadcast repeats of radio programmes several times for different time zones. The quality of dictating machines that recorded onto wire fell short of broadcasting standards, however in 1924, a film producer and inventor called Ludwig Blattner licenced a new machine, the Blattnerphone, that replaced wire with steel tape as its magnetic recording medium. The machine used 6 mm steel tape, and its basic audio signal was not considered good enough by BBC engineers for reproducing music, however it was adopted for recording and replaying speech. The Blattnerphone had several disadvantages. It required large and heavy spools of tape and operated at a high speed of 5 ft per second, making it hazardous to run; a break in the tape could result in razor-edged pieces of steel flying around the room. Recordings were not easy to edit, the tape itself requiring soldering. This was too laborious for regular productions using this technique, however in 1932 a programme was produced in the Blattnerphone room called ‘Pieces of Tape’ which compiled several tapes recorded that year.

Meanwhile, in Germany, advancements in magnetic recording were being made that would change the field entirely. In 1928, German inventor Dr Fritz Pfleumer experimented with applying magnetic powders to strips of paper or plastic film. This inspired the company AEG, who in 1932 began to use it as a principle on which to develop a device called the Magnetophone. AEG signed an agreement of collaboration with BASF: AEG developed the system, and BASF an appropriate sound carrier. In 1935 the reel-to-reel Magnetophone and its magnetic audio tape were first presented to the public at a Radio Fair in Berlin. Over the following years, further advancements (including the concept of AC tape bias) improved the sound quality and eliminated background hiss to a degree that made it difficult to tell whether a recording was playing live. During the Second World War, Magnetophon recorders were widely used in German radio broadcasts. Adolph Hitler used this to his advantage, performing what appeared to be live broadcasts from one city, while he was in fact in another. While the Magnetaphone had been released prior to the war, its improvements and advancements became closely guarded secrets. Allied forces were aware that Germany had a new system that could create pre-recorded material at a high quality and long duration, however, did not discover the full details of its construction or operation until the Allied invasion of Germany during 1944-45.
One of the people to introduce magnetic audio tape to the West was American Major John “Jack” Mullin of the U.S. Army Signal Corps. In 1944 he heard a Radio Berlin broadcast of the Berlin Philharmonic orchestra. The quality and duration of the recording far surpassed anything in operation by the Allied Forces and sounded like a live recording, however, at the time it was playing it was 3am in Berlin. After the war Mullin was assigned to discover what communications technology Germany had been operating and discovered high-fidelity Magnetophones in operation at a Radio Frankfurt station in Bad Nauheim. Mullin returned to America with two Magnetophones and fifty magnetic tape reels, which he worked to improve and amazed the attendees of the annual Institute of Radio Engineers (IRE) conference in San Francisco who were unable to tell whether the recordings they heard were live or pre-recorded. Not only this, but magnetic tape could easily be edited, by simply being cut and spliced together with tape. Mullin was hired by the singer Bing Crosby, who both hated performing live on radio and was attracted by the high fidelity of the Magnetophone. Crosby later became a key investor in the development of the first American reel-to-reel tape machines by the electronics company Ampex.

Reel-to-reel magnetic audio tape was used predominantly for professional purposes such as radio. When the compact cassette tape arrived in 1963, it introduced magnetic audio tape to the mass consumer market. Initially primarily intended for dictation, its popularity came from music and early recording artists to adopt the format included Nina Simone, Eartha Kitt, and Johnny Mathis. The first in-car cassette player was launched in 1968 and the portable cassette tape player the Sony Walkman was released in 1979. Commercial cassette tape recorders allowed the public to record music at home, recording songs from the radio to create their own copies and mix tapes, leading to the British phonographic Industry (BPI) launching a campaign called ‘Home taping is killing music’ in fear of declining record sales. Compact cassette tapes remained popular throughout the 1980s, despite the 1982 release of the first CD (Compact Disc). However, by the 1990s CD had began to monopolise the market and by the early 2000s most major music companies discontinued the production of pre-recorded compact cassettes.
Through the audio preservation project Unlocking Our Sound Heritage, Norfolk Record Office is preserving collections of reel-to-reel and compact cassette tapes to ensure that their recordings can be safeguarded for the future. Unlocking Our Sound Heritage is supported by the National Lottery Heritage Fund.