How did home audio evolve after World War II – from magnetic recording to new speakers

Last time, we talked about how records and radio changed the approach to listening to music at the beginning of the 20th century. Today we are talking about technologies that became widespread after the Second World War and once again changed the acoustic ecosystem in people’s homes.

Photo dom christie / CC BY

Magnetic sound recording

This technology allowed us to record high-quality sound and worry less about possible mechanical damage to the media. Although by the look at her early implementations it is difficult to say that she was destined to reverse the idea of ​​music. The father of magnetic recording is considered the Danish engineer Valdemar Poulsen, who at the end of the XIX century got a patent on steel wire audio recording technology and developed telegraph. But the device was not the most convenient to use and could not stand the competition with more affordable phonographs.

Although the situation changed with the beginning of World War II.

During the fighting, the wire carrier was used for audio recording in the field – it easily tolerated temperature changes and was not afraid of moisture. However, the playback quality left much to be desired. The problem was solved by German engineers, having developed a film with a deposition of iron oxide and using technology high frequency bias managed to improve the quality of sound recording. They used film recorders to propagate the time.

Photo jglazer75 / CC BY / Ampex Model 300
Magnetic tape spread around the world after the war ended, when American soldiers took confiscated equipment from Germany. One of them then developed a new playback device.

It saw light in 1948 – it was the Ampex Model 200 reel. The system quickly became an integral part of the recording studios, where it was used for mastering. But the installation had a drawback – it was too cumbersome.

One of the first to have this problem I decided Polish audio engineer Stefan Kudelsky. In 1951, he independently developed and assembled a prototype tape recorder NAGRA I (KDPV depicts its improved version – Nagra IV-S).

It was portable, the size of a small suitcase. For its convenience, the system has been recognized among television, radio and film workers. NAGRA players were used when climbing Mount Everest and during space missions.

Soon the bobbin holders became the most widespread. More and more companies began to produce them, and these devices could be found in the homes of a large number of people – including in the Soviet Union. Who made such devices in the USSR, we told earlier.

Long-playing vinyl

The technology of magnetic sound recording was supposed to overshadow the unreliable records that were made from shellac. But the records were not going to lose ground and give way to the music market without a fight. In 1948, shellac was replaced by new materials – vinyl and polyvinyl chloride. They were more durable and less noisy during playback.

In addition to the material, the technology of applying sound tracks was improved – it allowed to reduce the speed of rotation of the plate without loss in sound quality. As a result, the volume of the drive increased – more music began to fit on it. 12-inch shellac plates held for several minutes on one side, and the new vinyl could fit up to 23 minutes of audio.

This fact completely changed the approach to sound recording – before the records often contained only one song, now they began to post entire albums on them. But this topic is quite extensive and worthy of a separate material, so we will talk about the evolution of music next time.

Over time, not only the volume of the records changed, but also the number of tracks. Until the 60s, records were released in monoform, but at the end of this decade have appeared stereo records. In them, the left and right walls of the track were responsible for the corresponding playback channels.

By the mid-70s, the vast majority of vinyl releases came out in stereo – they played both in people’s living rooms and on radio stations.

New speakers

To appreciate the capabilities of the new audio formats – both magnetic tape and vinyl records – allowed electrodynamic loudspeakers. The first such devices were invented long before the war – they used electromagnetic capsule.

But their designs did not stand the test of time. Partly because such speakers had a high level of nonlinear and frequency distortion. Loudspeakers with a coil, magnet and diffuser came to replace them – they began to be mass-produced in the 1950s. From that moment, not even ten years had passed before the stereo equipment entered the scene.

One of the first appeared dual-channel tape recorders. They were followed by the production of commercial two-channel reels. In 1957 started development of stereo cartridges for vinyl players, and a year later the first commercial stereo album entered the music market. We will talk about how new music developed in the next article.

Additional reading on the topic in the “Hi-Fi World”:

How home audio developed – from song nights to first players
How home audio has become available to a wider audience
Why did vinyl come back, and how are streaming services related to this?
Finds of an audio man: where to listen to the music of bygone eras
History of Audio Technology: Synthesizers and Samplers

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