Spinning back time: the Edison Voicewriter and its Diamond Discs
In recent years, our Audiovisual Preservation officers at the State Library have concentrated their efforts on magnetic media and Deadline 2025. But we recently paused to peek at an obscure audio oddity that’s under consideration for our collection: the Edison Voicewriter.
The Voicewriter electronic dictation machine was developed in the early 1940s and released to market at the end of World War II. It records onto 7-inch, flexible, translucent red polymer discs. Our example, a model DPC-1, was purchased in the 1950s from Parsons & Robertson Ltd on Pulteney Street for about £250. That’s equivalent to almost AUD $10,000 today!
The machine uses a special vertical mechanism to emboss sound onto the provided ‘Diamond Discs’. This method is at odds with the phonographic standard of cutting horizontal grooves, but it also happens to be the recording technique described by inventor of the phonograph, Thomas A Edison, in his original 1877 patent.
We’ve yet to determine if our Voicewriter unit is safe to operate, but luckily the recorded discs play on any consumer turntable. There are caveats, however: a quality modern stylus may struggle to track the less-than-perfect embossed grooves, and the Voicewriter’s rotational speed is about 22rpm, so the sound is ‘sped up’ when played on a 33/13 rpm turntable.
We have digitally ‘slowed down’ some Diamond Discs that document a worldwide business trip. The thin, lightweight discs were stuffed into Edison-branded envelopes and mailed from the 1st Class deck of the SS Stratheden back home to Adelaide.
This illustrates a distinct advantage over the wax cylinders used in Edison’s earlier Ediphone dictation machine. Diamond Discs are also smaller, more durable, and sound better than cylinders, making the Voicewriter a key stage in the evolution of voice recording technology.
And although susceptible to dings and creases, the discs cannot be erased - perhaps this is why the Voicewriter remained popular in business settings even after the next seismic shift in sound recording technology: magnetic tape.
These Diamond Discs are part of a larger yet-to-be-catalogued Harold Anderton Lightburn collection (SLSA: ACC 2364) is currently unavailable due to a temporary pause in offsite collection access, we look forward to sharing this fascinating material in the future.
Written by the Digitisation and Digital Preservation Team
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