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Formats
Radio
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| A reel of recording wire. [Click photo to
enlarge.] |
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.
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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 World War Two. Their repair kits included
extra wire, grips and a soldering iron.
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| Some early acetate discs were 16 inches in diameter.
There are now few turntables large enough to accommodate them.
[Click photo to enlarge.] |
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).
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| There are numerous varieties and brands of ¼-inch
tape and so there are various ways of transferring them to a
digital format. [Click photo to enlarge.] |
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 1/4-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 so-called "easy
bake" oven before playing often corrects this problem.
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| DAT (Digital Audio Tape) was the first digital
format used by the Radio Archives for storage. Its regular use
has now been superseded by the use of the CD for CD-ROM or CDA
recording. [Click photo to enlarge.] |
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. In 1999, CDs took their place
and remain the medium of choice today.
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