Sound Recording and Reproduction - Electrical Recording

Electrical Recording

Between the invention of the phonograph in 1877 and the advent of digital media, arguably the most important milestone in the history of sound recording was the introduction of what was then called "electrical recording", in which a microphone was used to convert the sound into an electrical signal that was amplified and used to actuate the recording stylus. This innovation eliminated the "horn sound" resonances characteristic of the acoustical process, produced clearer and more full-bodied recordings by greatly extending the useful range of audio frequencies, and allowed previously unrecordable distant and feeble sounds to be captured.

Sound recording began as a purely mechanical process. Except for a few crude telephone-based recording devices with no means of amplification, such as the Telegraphone, it remained so until the 1920s, when recent radio-related developments in electronics converged to revolutionize the recording process. These included improved microphones and auxiliary devices such as electronic filters, all dependent on electronic amplification to be of practical use in recording. In 1906 Lee De Forest began selling the "Audion" triode vacuum tube, an electronic valve which could greatly amplify weak electrical signals. By 1915 it was being used in long-distance telephone circuits that made it possible to talk between New York and San Francisco with both parties being clearly heard. Refined versions of this tube were the basis of all electronic sound systems until the commercial introduction of the first transistor-based audio devices in the 1950s.

During World War I, experiments were undertaken in the United States and Great Britain to record and reproduce, among other things, the sound of a German U-boat (submarine) for training purposes. The acoustical recordings of that time proved entirely unable to reproduce the sounds, so other methods were actively sought. The earliest results were not very promising. The first electrical recording issued to the public, with little fanfare, was of the 11 November 1920 funeral services for the Unknown Soldier in Westminster Abbey, London. The microphones used were like those in contemporary telephones. They were discreetly set up in the abbey and connected by wires to recording equipment in a vehicle outside. Although electronic amplification was used, the resulting audio was weak and very unclear. The novel procedure did, however, allow a recording to be made which would otherwise not have been practical in those circumstances. For several years, this little-noted disc remained the only issued electrical recording.

Several record companies and independent inventors, notably Orlando Marsh, were experimenting with equipment and techniques for electrical recording in the early 1920s. Marsh's electrically recorded Autograph Records were already being sold to the public in 1924, a year before the first such offerings from the major record companies, but their overall sound quality was too low to demonstrate any obvious advantage over traditional acoustical methods. Marsh's microphone technique was idiosyncratic and his work had little if any impact on the systems being developed by others.

Telephone industry giant Western Electric had research laboratories (merged with the AT&T engineering department in 1925 to form Bell Telephone Laboratories) with material and human resources that no record company or independent inventor could match. They had the best microphone, a condenser type developed there in 1916 and greatly improved in 1922, and the best amplifiers and test equipment. They had already patented an electromagnetic recorder in 1917, and in the early 1920s they decided to intensively apply their hardware and expertise to developing two state-of-the-art systems for electronically recording and reproducing sound: one that employed conventional discs and another that recorded optically on motion picture film. Their engineers pioneered the use of mechanical analogs of electrical circuits and developed a superior "rubber line" recorder for cutting the groove into the wax master in the disc recording system.

By 1924 such dramatic progress had been made that Western Electric arranged a demonstration for the two leading record companies, the Victor Talking Machine Company and the Columbia Phonograph Company. Both soon licensed the system and both made their earliest published electrical recordings in February 1925, but neither actually released them until mid-year. To avoid making their existing catalogs instantly obsolete, the two long-time arch rivals agreed privately not to publicize the new process until November 1925, by which time enough electrically recorded repertory would be available to meet the anticipated demand. During the next few years the lesser record companies licensed or developed other electrical recording systems. By the end of the 1920s only the budget label Harmony was still issuing acoustically recorded discs.

Comparison of some surviving Western Electric test recordings with early commercial releases indicates that their system had been "dumbed down" by the record companies so as not to overwhelm non-electronic playback equipment, which reproduced very low frequencies as an unpleasant rattle and rapidly wore out discs with strongly recorded high frequencies.