Magnetic tape recording was invented in the early years of the Twentieth Century and became useful as a device for recording speech, but simply for the information content, as in a dictation machine – the sound quality was too poor.
In essence, a tape recorder converts an electrical signal to a magnetic record of that signal. Electricity is an easy medium to work in, compared to magnetism.
It is straightforward to build an electrical device that responds linearly to an input. 'Linear' means without distortion – like a flat mirror compared (linear) to a funfair mirror (non-linear).
Magnetic material does not respond linearly to a magnetizing force.
When a small magnetizing force is applied, the material hardly responds at all. When a greater magnetizing force is applied and the initial lack of enthusiasm to become magnetized has been overcome, then it does respond fairly linearly, right up to the point where it is magnetized as much as it can be, when we say that it is 'saturated'.
Unfortunately, no-one has devised a way of applying negative feedback to analog recording, which in an electrical amplifier reduces distortion tremendously.
Early tape recorders (and wire recorders) had no means of compensating for the inherent non-linearity of magnetic material, and it was left up to scientists in Germany during World War II to come up with a solution.
The tape recorder was apparently used to broadcast orchestral concerts at all hours of day and night, to the consternation of opposing countries who wondered how Germany could spare the resources to have orchestras playing in the middle of the night. (Obviously, recording onto disc was possible, but the characteristic crackle always gave the game away).
After hostilities had ceased, US forces brought some captured machines back home. At this point, improved though it now was, the tape recorder was an invention looking for an application.
That application came in the unlikely form of singer Bing Crosby's radio show, 'The Crosby Show'. In around 1946 and 1947, Bing was recording his show onto 16-inch records and editing them by copying from two players to a lathe, much like today's DJs mix their records live (without the lathe of course). Sometimes however they wanted edits so close together that it just wasn't possible to cue the discs quickly enough, so they ended up with multiple generations of copying, further degrading the sound quality with each generation.
For the 1947-48 season of The Crosby Show, Crosby's staff compared the new tape recorder with their disc systems. They found that the flexibility of being able to edit tape by cut-and-splice techniques far better than editing on disc. The original German Magnetophon machines were copied and improved upon by Ampex, and the era of analog tape recording truly began.
It is worth noting that the perpetrators of The Crosby Show are also responsible for inventing the 'laugh track' that now accompanies almost every TV comedy show.
The above article was based on research provided by a historian of the times. A Audio Masterclass visitor, who unfortunately did not leave his name, adds the following perspective, which is even more illuminating…
“The playback of 16” acetate transcriptions would not have had any crackle – only the then-popular 78 rpm discs might have (and that is might) since they would have been kept in pristine condition at a radio station. Before the Germans perfected tape recording (which used paper tape with an oxide coat) broadcasters all over the world used actetate or lacquer transcription recordings, a 16 inch disc revolving at 33.3 rpm, the same as later Long Playing records – the only difference being the size of the groove, tackled sucessfuly by US Columbia and RCA Victor, the latter with 45 rpm discs, but a similarly sized “microgroove”. What did puzzle the Allies was not so much orchestras in the night but how Hitler managed to get from A to B so quickly, not realizing that the speeches were recorded on tape. I have read that when the Allies eventually went to the radio stations, the tape recorders were divided up between the countries, one each to Britain , Russia and the United States, the US was not the only country to get one. Transcription discs were as quiet as any tape and exactly the same process used for 'cutting a lacquer' in the manufacure of vinyl LPs. Only when they were misused or allowed to get dirty was there any residual noise. Because tape was not considered safe for archival purposes (drop-out etc) it was not until 1976 that NBC Radio in America stopped using transcription recordings for archival purposes and then their enormous collection was donated to the Library of Congress.
“Bing Crosby used the convenience of tape recording so that he could record all his own parts for the show, without having to wait for the other artists! Editing may have been a factor, but apparently convenience was uppermost in his mind!”