Transcription disc

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A transcription disc is a special phonograph record intended for, or recorded from, a radio broadcast. Sometimes called a broadcast transcription or radio transcription or nicknamed a platter, the official term was electrical transcription, usually abbreviated to E.T. among radio professionals.

Transcription discs are most commonly 16 inches (40 cm) in diameter and recorded at 33 1/3 rpm. That format was standard from approximately 1930 to 1960 and physically distinguishes most transcriptions from records intended for home use, which were rarely more than 12 inches (30 cm) in diameter and until 1948 were nearly all recorded at approximately 78 rpm. However, some very early (circa 1928-1931) radio programs were on sets of 12 inch (30 cm) or even 10 inch (25 cm) diameter 78 rpm discs, and some later (circa 1960-1985) syndicated radio programs were distributed on 12 inch (30 cm) diameter 33 1/3 rpm microgroove vinyl discs visually indistinguishable from ordinary records except by their label information.

Some unusual records which are not broadcast-related are sometimes mistakenly described as "transcription discs" because they were recorded on the so-called acetate recording blanks used for broadcast transcriptions or share some other physical characteristic with them. Transcription discs should not be confused with the 16 inch diameter, 33 1/3 rpm shellac soundtrack discs used from 1926 into the early 1930s to provide the audio for some motion picture sound systems. Also a potential source of confusion are RCA Victor's "Program Transcription" discs, 10 or 12 inch diameter 33 1/3 rpm records pressed in shellac and "Victrolac" vinyl in the early 1930s. Despite their suggestive name, they were not recorded from broadcasts or intended for broadcast use, but were an early and unsuccessful attempt to introduce longer-playing records at the 33 1/3 rpm speed for home use.

Disc types[edit]

Transcription discs are of two basic types: pressings and instantaneous discs.

Pressings were created in the same way as ordinary records. A master recording was cut into a blank wax or acetate disc.[1] This was electroplated to produce a metal stamper from which a number of identical discs were pressed in shellac or vinyl in a record press. Although the earliest transcription discs were pressed in shellac, in the mid-1930s quieter vinyl compounds were substituted. These discs were used to distribute syndicated programming to individual radio stations. Their use for this purpose persisted long after the advent of magnetic tape recording because it was cheaper to cut and plate a master disc and press 100 identical high-quality discs than to make 100 equally high-quality tape dubs.

Instantaneous discs are so called because they can be played immediately after recording without any further processing, unlike the delicate wax master discs which had to be plated and replicated as pressings before they could be played non-destructively. By late 1929, instantaneous recordings were being made by indenting, as opposed to engraving, a groove into the surface of a bare aluminum disc. The sound quality of these discs was inadequate for broadcast purposes, but they were made for sponsors and performers who wanted to have recordings of their broadcasts, a luxury which was impractically expensive to provide by the wax mastering, plating and pressing procedure. Only a very few pre-1930 live broadcasts were deemed important enough to preserve as pressings, and many of the bare aluminum discs perished in the scrap metal drives of World War II, so that these early years of radio are mostly known today by the syndicated programs on pressed discs, typically recorded in a small studio without an audience, rather than by recordings of live network and local broadcasts.

In late 1934, a new type of instantaneous disc was commercially introduced. It consisted of an aluminum core disc coated with black cellulose nitrate lacquer, although for reasons which are unclear it soon came to be called an "acetate" disc by radio professionals. Later, during World War II, when aluminum was a critical war material, glass core discs were used. A recording lathe and chisel-like cutting stylus like those used to record in wax would be used to engrave the groove into this lacquer surface instead. Given a top-quality blank disc, cutting stylus, lathe, electronics and recording engineer, the result was a virtually noiseless broadcast-quality recording which could be played several times before the effects of wear started to become apparent. The new medium was soon applied to a number of purposes by local stations, but not by the networks, which had a policy against broadcasting prerecorded material and mainly used the discs for archiving "reference recordings" of their broadcasts.

Standard 16 inch transcription discs of the 1930s and 1940s usually held about 15 minutes of audio on each side, but this was occasionally pushed to as much as 20 minutes. Unlike ordinary records, some were recorded inside out, with the start of the recording near the label and the end near the edge of the disc. The label usually noted whether the disc was "outside start" or "inside start". If there was no such notation, an outside start was assumed. Beginning in the mid-1950s, some transcription discs started employing the "microgroove" groove dimensions used by the 12 and 10 inch 33 1/3 rpm vinyl LP records introduced for home use in 1948. This allowed 30 minutes to fit comfortably on each side of a 16 inch disc. These later discs can be played with an ordinary modern stylus or a vintage "LP" stylus. The earlier discs used a larger groove, nearer in size to the groove of a typical 78 rpm shellac record. Using a "78" stylus to play these "standard groove" discs usually produces much better results, and also insures against the groove damage that can be caused by the point of a too-small stylus skating around in the groove and scoring its surface. Some specialist audio transfer engineers keep a series of custom-ground styli of intermediate sizes and briefly test-play the disc with each in order to find the one that produces the best possible results.

Notable uses[edit]

The network ban on prerecorded material was temporarily lifted on the occasion of the crash of the airship Hindenburg in Lakehurst, New Jersey on 6 May 1937. A recording of the crash made for Chicago radio station WLS by announcer Herbert Morrison was allowed to be broadcast over the network by NBC. This is the well-known "oh, the humanity!" recording, usually heard only as a brief excerpt and reproduced at a speed which differs significantly from the original recording speed, causing Morrison's voice to sound unnaturally high-pitched and excessively frantic. When heard in its entirety and at the correct speed, the report is still powerful.

Transcription recordings from major American radio networks became commonplace during World War II as pressed vinyl copies of them were distributed worldwide by the U.S. Armed Forces Radio Service for rebroadcast to troops in the field. Disc-to-disc editing procedures were used to delete the commercials included in the original broadcasts, and when a sponsor's name was attached to the name of the program, it was removed as well—Lux Radio Theater, for example, became Your Radio Theater. Although the discs were government property and were supposed to be destroyed after they had served their purpose, some were saved as souvenirs and countless thousands of them were simply dumped rather than actually destroyed. Many of the dumped discs ended up in the hands of scavengers and collectors. Often, these discs are the only form in which the broadcasts on them have survived, and they are one of the reasons why recordings of entertainment broadcasts from the 1940s still exist in abundance.

Well-known live broadcasts which were preserved on lacquer transcription discs include The War of the Worlds dramatized as breaking news by the Orson Welles anthology program The Mercury Theatre on the Air, heard over the CBS radio network on 30 October 1938.

Before magnetic tape recorders became available in the U.S., NBC Symphony Orchestra concert broadcasts were preserved on transcription discs. After its conductor Arturo Toscanini retired, he transferred many of these recordings to tape, with the assistance of his son Walter, and most were eventually released on LP or CD.[2]

In the United States, NBC Radio continued to use the 16 inch disc format for archiving purposes into the early 1970s.

Notable transcription disc production & distribution companies[edit]

See also[edit]

References and notes[edit]

  1. ^ Although the word "acetate" has long been standard in the broadcast industry and has come into general use, that term was and is abhorred as technically incorrect by engineers in the record industry, who refer to the discs as "lacquers", because the lacquer coating on them is actually cellulose nitrate, not cellulose acetate.
  2. ^ Harvey Sachs, Toscanini (1978)
  3. ^ "Muzak Studios In NY Bought by RCA Victor", Billboard, September 1, 1951, pg. 11

External links[edit]