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CBC Digital Archives

Radio

Over the years, the CBC has relied on many different technological formats to produce, play and preserve its audio and video programming. Though some may seem quaint, or utterly archaic, today, it's worth remembering that all were state-of-the-art in their time. It's also easier to appreciate the sounds and pictures coming out of the archives today if you know a little bit about how these different formats worked and how they evolved.

The 1930s and '40s: Wire

Before there were tape recorders, there were wire recorders. As with tape, the key to the technology was magnetization - if the wire was magnetized, you could record on it. Field correspondents used portable versions in the Second World War. Their repair kits included extra wire, grips and a soldering iron.

The 1950s and '60s: Acetate discs

In the archives' early years, the CBC recorded radio sound on 16-inch acetate transcription discs. Made of glass, metal or even paper with a thin layer of acetate fixed to the surface, these discs were used until 1966. They look similar to commercial vinyl records except they were larger, thicker and heavier. Recordings were made by carving a groove in the acetate with a needle; a tiny vacuum was mounted on the end of needle arm to remove the acetate residue. Very durable, discs were usually recorded at one of two speeds - 33- or 78-rpms - and could be engraved either from the outside in or the inside out (a small icon on the disc indicates which direction was used).

The 1960s: Acetate tape

Acetate tape was first introduced for recording in the 1950s. The archives only started using it for storage and copying in 1966. While it produced a fine sound, it did not age well. Over time, acetate tape curls, shrinks and loses mass. Because it does not readily stretch or deform (a bonus) it tends to break easily (a drawback).

The 1970s: Polyester tape

The Archives switched to the more durable polyester tape in the 1970s. Home users may remember the ¼-inch reel-to-reel tape that was popular before cassettes. In terms of composition, polyester tape was very similar to the tape still in use today. While the sound quality is excellent, polyester tape deforms easily, so users must be careful not to stretch it. Also, a lot of polyester tape made between 1975 and 1985 caused later problems for archivists because it began to shed a sticky residue which damaged both tapes and equipment when played. Gentle heating in the oven before playing often corrects this problem.

The 1980s to present: Digital formats

The Archives entered the digital age with the move to Digital Audio Tape (DAT) for audio storage in 1988. CDs took their place in 1999.






Next Page : Formats: Television