Wire Recording - Media Capacity and Speed

Media Capacity and Speed

Compared to tape recorders, wire recording devices had a high media speed, made necessary because of the use of the solid metal medium. Standard postwar wire recorders used a nominal speed of 24 inches per second (610 mm/s), making a typical one-hour spool of wire 7,200 feet (approx. 2200 m) long. This enormous length was possible on a spool less than 3 inches in diameter because the wire was nearly as fine as hair. 30 and 15 minute lengths of wire were also available on these small spools, which were employed by the majority of recorders made after 1945. Some heavy-duty recorders used the larger Armour spools, which could contain enough wire to record continuously for several hours. Because the wire was pulled past the head by the take-up spool, the actual wire speed slowly increased as the effective diameter of the take-up spool increased. Standardization prevented this peculiarity from having any impact on the playback of a spool recorded on a different machine, but audible consequences could result from substantially altering the original length of a recorded wire by excisions or by dividing it up onto multiple spools.