The Golden Age of recording made use of the acoustical system, which involved no transfer of sound-wave patterns into electricity. Most records except the Pathes, early OKehs and the dying Edison Bells of earlier years were cut according to the Berliner side-to-side groove method. They still are today 33s, 45s, and 78s. The basic manner in which grooves are made first in soft material, later to be reproduced in quantity, was not markedly different in the early nineteen-hundreds than now, though the intervening steps between the creation of the sound and the cutting of the groove are vastly changed. Then, as now, wave patterns were recorded in the form of a wobbling spiral groove; then, as now, music was re-made by retracing these grooves, or their reproduced offspring, with a pointed needle or stylus.
The present-day microphone is a transducer (an expressive term used by engineers for any device which converts or "translates" intelligible energy from one form into another) that converts sound waves into minute electrical impulses carrying the sound pattern. In the old recording there was no microphone and no electricity; the transducer was purely acoustical or mechanical, a sort of diaphragm system which vibrated according pressure waves of a very loud sound to the horn-concentrated - Caruso's voice a foot or so away, for instance - transmitting this actual physical motion directly to the stylus that cut the original wax record groove.
The acoustical system, even in its later stages, was relatively crude and thoroughly unfaithful to the sound it recorded. Its message, to be sure, was intelligible, and that was what mattered. But to call it "reproduction" was truly imaginative! Luckily for us, we all indeed imaginative in our listening to an extraordinary degree. Only think for a moment of the strange, garbled noises that we are able to interpret in our minds as intelligible language or music. Whether it's a portable radio ridden with static, a long-distance telephone message, or an old-style record, we are easily able to ignore the distortions and fill in the missing sounds that turn noise into sense.
The really basic limitations of the acoustical record, then, were strangely enough to he found quite elsewhere than in its mere lack of quality in the sound. And the greatest was one which few of us now stop to remember in this day of unlimited amplification of sound-the fact that the entire energy for the actual recording came from the original sound itself. There was no amplification, no way to make a little sound into a bigger one. It took a loud noise - tremendously loud - to make a loud record, and even that had to be concentrated to top intensity by means of huge horns.
No wonder the operatic record became a favorite - it was almost the only feasible kind of music to record! Piano and violin were recorded after a fashion; special "orchestral" instruments were invented to furnish those feeble, thumping backgrounds we still can hear on the old disks - five or six or even a dozen players with strange, misshapen instruments on which they blotted and squawked forth a semblance of "symphonic" accompaniment into the ever-present horn. But the human voice was the outstanding success, for it combined concentrated sound power with an extraordinary emotional and theatrical persuasiveness.
But place the voice twenty feet distant from a recording horn, and the enormously diminished energy (plenty for our sensitive ears) could scarcely move the insensitive recording stylus at all. Nothing that could not produce violent sound, practically inside the horn, was of any use. Symphonic music - indeed, any sort of natural instrumental music-was clearly out of the question.
And in the same way, the mechanical or acoustical reproducing phonograph also depended for its sound power upon the actual shape of the record grooves, the strength of side-to-side motion which those grooves could generate in the directly coupled needle and diaphragm that reversed the recording process, to throw out a feeble sound from a horn's mouth. Again, there was no amplification, only the conservation of as much of the precious groove energy as possible. The fancy reproducing horns and later devices, such as the fluted and twirled orthophonic reproducer head, were no more than elaborate ways to reinforce and concentrate the tiny fund of energy available when the phonograph needle was dragged along the wavering record groove. "Loud" needles passed along a maximum of this energy to the phonograph's horn and out in the open in old models, built into later cabinets. "Soft" needles, deliberately inefficient, permitted less of it to get to your ears. Other than the choice of needle, the only volume control possible in those days was a set of adjustable doors - a most unsatisfactory way of controlling what feeble sound power the machine could muster. Until a way could be found greatly to enlarge the sound pattern, keeping its shape an its meaning more or less intact, not a thing could be done toward fundamental improvement.