Prior to 1925, all recording was done "acoustically", which is to say, "mechanically". The sound waves created by a voice or instrument were concentrated through a funnel-shaped "horn" in order to vibrate a thin membrane, or "diaphragm". The vibrating diaphragm had connected to it some sort of stylus or cutting point which engraved the motion of the diaphragm in response to the sound waves into a soft material such as wax. For playback, the process was essentially reversed, and the undulating groove manipulated the stylus, which in turn vibrated the diaphragm -- reproducing what has been recorded.

There were two fundamental applications of acoustical recording technology:
Edison's method [1] using cylinder-shaped recordings made initially of wax, and later celluloid, was based upon his earliest tinfoil phonograph research of 1877-1879. In this approach, known as "vertical [2]" recording, the recording point moved up-and-down in a vertical motion engraving the undulations of sound on the bottom of the groove which wrapped tightly and continuously around the circumference of a rotating cylinder. Very similar experiments were independently conducted by Chichester Bell [3] and Charles Sumner Tainter [4] that eventually resulted in the formation of Edison's largest competitor in the cylinder business, the Columbia Graphophone Company [5].

In 1887, Emile Berliner [6], a German immigrant living in Washington, D.C., who had been employed for a time in the laboratory of Bell and Tainter, developed an alternate recording method, in which similarly, a horn concentrated sound waves against a diaphragm, but this time, moving the cutting stylus in a side-to-side motion relative to the groove, and inscribing onto the surface of a revolving disc, rather than a rotating cylinder. Berliner termed this method "lateral [7]" recording. Berliner named this machine the "Gramophone [8]". Subsequent improvements in Berliner's methods and recording and reproducing apparati, primarily by Berliner himself, Werner Suess, Eldridge Reeves Johnson [9], Alfred Clark, Fred Gaisberg [10], William Sinkler Darby, Leon F. Douglass [11] and others, eventually resulted in the founding and operation of the Victor Talking Machine Company [12] from 1901.

Berliner's method was not as technologically "pure" as Edison's cylinder method since the surface speed of a disc at a given point in the groove decreases the closer that point is to the center of the disc resulting in diminished frequency response; the tangential angle of the stylus in relation to the circumference of the groove does not remain constant across the surface of the disc resulting in "tracking" error; the stylus, reproducer, horn, support arm, and any other part traversing the disc is constantly fighting centrifugal force as the groove draws it to the center; and the sideways movement of the recording stylus during loud passages often caused the stylus to blow through or deform adjoining groove walls.

Edison's cylinder format [13] offered a constant groove diameter and thus a constant surface speed with no tracking error or centrifugal force problems, and since the recording was at the bottom of the groove, rather than on the sides, there was no danger of blowing through neighboring grooves. Cylinders had less surface noise than early lateral discs, but improvements in disc recording and pressing processes made them sonic equals by 1908.

The greatest advantages the disc had over the cylinder were in ease, speed and low cost of production for the manufacturers; and handling and storage for the consumer. Cylinders were more labor intensive and more expensive to manufacture, package and ship, and sold for less than discs, resulting in a lower profit margin for Edison.

For retailers and consumers, cylinders took up more space to store and were more delicate to handle than discs, especially fragile pre-1913 wax cylinder issues. Later advances, such as "unbreakable" celluloid cylinders and longer playing four-minute releases that matched the playing time of 12" discs, came too late to rescue the cylinder format. Edison's chief competitor in the cylinder format, Columbia, saw the writing on the wall and abandoned the format in 1909 to produce only lateral discs. By 1911, Edison was the sole cylinder manufacturer in the country, a format he doggedly continued to champion (and improve) until shortly before the phonograph division ceased production in October 1929.

Although the simple technological differences between vertical and lateral recording spurred countless inventive minds, generated hundreds of patent lawsuits, and both created and destroyed business empires, fortunes, and lives in the process, they were still both acoustical/mechanical processes. Much of the development of acoustical recording was by less than empirical science. Every possible variable that might affect the recording process, from the size, shape and material that a recording horn might be constructed, to the diameter, thickness and material that the diaphragm might be fashioned from, and every imaginable theoretical variant was tried in every possible combination until a satisfactory result was achieved. Different voices -- mezzo-soprano, soprano, alto, contralto, tenor, baritone, bass -- would require different horns and different recorders in different combinations. The same for various instruments, ensembles, bands, orchestras, whistlers, yodelers and elocutionists. Two different individuals with tenor voices might require completely different horns and recorders from one another, and different gear might be required to record the same subject on a different day, or even at a different time of day as temperature and humidity would change (in those pre-climate controlled days) and affect the density and character of the very air in the studio and the yielding quality of the wax recording blank. Securing a successful record was more of a combination of tinkering and alchemy than real science.

Very little was patented during this period lest a competitor learn what a company was up to and copy their secrets. Recording engineers were typically among the most highly paid employees of a company in order to prevent them from jumping ship and taking their secrets with them. The recording equipment, recorders, and horns were built by the engineers themselves and were considered proprietary. Break-ins and industrial espionage were commonplace. The recording lathe and associated apparatus were locked behind closed doors, only the recording engineer allowed to see it. Protruding through the wall would be the recording horn, or horns, into which the artists would sing or play. The recording engineer would frequently stand right by the performer, and physically move them nearer and further to the horn as the engineer saw fit, to avoid blasting through adjacent grooves during fortissimo passages.

Only certain instruments and voices with a certain "quality" were powerful enough to drive the diaphragm enough produce a successful recording. Softer instruments such as guitars, violins, autoharps, mandolins, etc., and "untrained" natural voices could not be effectively or consistently recorded using acoustical recording methods. In an attempt to capture the minute vibrations of stringed instruments, Augustus Stroh [14], an inventor and machinist who was active in phonographic innovation since its inception in tinfoil days, produced the Stroh Violin. Designed especially for recording purposes, the bridge rested on a diaphragm. From the housing of the diaphragm protruded two brass horns, one pointing toward the ear of the violinist, the other outward toward the recording horn.