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Figure 6. Disc phonograph designed by Maxfield and Harrison by means of equivalent circuits. The record on the turntable is played by a soundbox connected through a sound conduit to the large horn with its square opening at the front of the phonograph. From Har- rison (1930).
The almost revolutionary consequence of electrical record- ing was that by means of a meter, it was now possible to monitor the volume or amplitude of the signal that was go- ing to be engraved on the master record. This meant that soft passages could be amplified more to provide a signal that was lifted well out of the background noise. And strong passages could be reduced in amplitude to avoid distortion. After 30 years of trial and error that had been required in acoustic recording, it was now possible to obtain a reliable quality. This represented a huge saving in cost.
A marked difference developed between the United States and Europe: the United States was quick to adapt to a purely electrical reproduction with a pickup, amplifier (mostly the amplifier already available in a radio set), and loudspeaker, whereas in Europe acoustic reproduction was common until about 1940. In fact, in 1947 in the United Kingdom, 25% of the reproducing equipment was still acoustic and the record companies had to equalize their recordings correspondingly (Mittell, 1947). In the overseas markets supplied from the United Kingdom (i.e., excluding the United States), the pro- portion was closer to 75%.
The Introduction of Acoustic Space Design for Recording Purposes
When the record companies introduced recording large en- sembles about 1912, the crowding of musicians around the mouth of the recording horn or horns was very tight and the ambience of the recording studio was rarely captured in a recording. However, as permanent recording installations became the norm, it also became possible to utilize some of the room acoustics. To be able to adapt the room acoustics to the performance, the Gramophone Co. in Hayes, Middle- sex, UK, starting about 1912, used a very special recording studio. It had been designed with walls covered in pine and had a ceiling that could be adjusted in height by a rack-and- pinion system. The US partner of the Gramophone Co., which was the Victor Talking Machine Company, had no interest in room ambience, as reported only five years earlier by the chief recording expert of the Gramophone Co., Fred W. Gaisberg, subsequent to a visit. They kept the windows of the recording room open in the summer (Brock-Nannestad, 1997), which would surely have destroyed any reverberation.
When electrical recording took off starting in 1926, the flex- ibility in microphone placement created a huge change in the approach. Instead of musicians crowding around the recording horn, microphones were placed near the instrument groups, and the soloist was provided with one all to himself/herself.
The Work on Types of Groove Modulation: Cutterheads and Pickups
The two types of modulation of the groove have already been mentioned: the oldest was the vertical or hill-and- dale, but the commercially surviving modulation was the lateral modulation (sometimes called Berliner; Figure 1). When the stereo groove came along in the 1950s, the two (orthogonal) sides of the groove had different modulations, and each was effectively hill-and-dale. However, in profes- sional recording, either in broadcasting or in academic field recordings, the vertical recording prevailed for much of the 1930s. In broadcasting, the fact that the modulation was out of the plane of the record meant that the grooves could be narrower, making space for longer recordings on each side of a record. In field work, acoustic phonographs were fre- quently still used at the end of the 1930s, the main reason being independence of electrical power. Furthermore, a wax cylinder in its protective box could be less fragile than a re- corded instantaneous record in a sleeve. But the phonograph cylinder survived well into the 1960s in its original intended use, office dictation.
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