the flexi disc made its first (and last) appearance in Spectrum, accompanying an article entitled “Voice signals: bit-by-bit,” written by Jon W. Bayless, S. Joseph Campanella, and A.J. Goldberg. The piece provided an overview of the emerging field of voice digitization, which the authors suggested might alleviate the stress placed on global telecommunications networks by increased demand for long-distance and overseas phone calls. It was a prescient prediction, given that analog telephones are close to becoming extinct today. //

Most of the article is devoted to technical descriptions of these competing methods, but the authors realized that a written summary could not fully convey the experience of listening to digitized voices. As a result, they collaborated with colleagues at academic, military, and industrial laboratories to record samples of various speech digitization techniques. The recording lasts just under six minutes and contains fourteen audio excerpts, each consisting of a few sentences that were generated using different methods and sampling rates. The resulting passages are frequently nonsensical, but the words themselves are less important than any noise or distortion resulting from the digitization process.

This flexi disc is, in effect, an audio time capsule preserving the state of speech digitization research in the early 1970s. //

There is something elegantly recursive about watching this flexi disc revolve on the turntable and hearing the resulting stream of sample sentences. After all, this is a digital video of an analog record that contains samples of digitized human speech. Variations of the PCM and vocoder techniques that are being demonstrated here are still used to encode audio signals today.

Beyond its significance as an artifact of the early days of digital audio, this flexi disc is also a reminder of the ongoing value of libraries and archives to 21st century researchers. Databases like IEEE Xplore allow users to review a vast amount of scientific and technical literature, but they are not comprehensive. There are still plenty of books and journals that have never been scanned, not to mention multimedia materials that might be more complicated to digitize or distribute. Whether one considers audio recordings or scarcely-held publications, sometimes there is just no substitute for consulting the original source.