Early History
A device utilizing a vibrating pen to graphically represent sound on discs of paper, without the idea of playing it back in any manner, was built by Edouard-Leon Scott of France in 1857. While the mechanism, known as a phonautograph, was intended solely to depict the visual characteristics of sound, it was recently realized that this depiction could be digitally analyzed and reconstructed as an audible recording. Just such an early phonoautogram, made in 1860 and now the earliest known audio recording, has been reproduced using computer technology.
In 1877, Thomas Edison developed the phonautograph into a machine, the phonograph, that was capable of replaying the recordings made. The recordings were made on tinfoil, and were initially intending to be used as a voice recording medium, typically for office dictation.
This phonograph cylinder dominated the recorded sound market beginning in the 1880s. Lateral-cut disc records were invented by Emile Berliner in 1888 and were used exclusively in toys until 1894, when Berliner began marketing disc records under the Berliner Gramophone label. The Edison Blue Amberol Record was introduced in 1912, with a longer playing time of around 4 minutes (at 160 rpm) and a more resilient playing surface than its wax predecessor, but the format was doomed due to the difficulty of reproducing recordings. By November 1918 the patents for the manufacture of lateral-cut disc records expired, opening the field for countless companies to produce them, causing disc records to overtake cylinders in popularity. Production of Amberol cylinders ceased in the late 1920s. Disc records would dominate the market until they were supplanted by the Compact Disc, starting from the late 1980s.
Structure
The sound quality and durability of vinyl records is highly dependent on the quality of the vinyl. During the early 1970s, as a cost-cutting move towards use of lightweight, flexible vinyl pressings, much of the industry adopted a technique of reducing the thickness and quality of vinyl used in mass-market manufacturing, marketed by RCA Victor as the "Dynaflex" (125 g) process, considered inferior by most record collectors.[30] Most vinyl records are pressed from a mix of seventy per cent virgin vinyl and thirty per cent recycled vinyl.
New "virgin" or "heavy/heavyweight" (180–220 g) vinyl is commonly used for modern "audiophile" vinyl releases in all genres. Many collectors prefer to have 180 g vinyl albums, and they have been reported to have a better sound than normal vinyl. These albums tend to withstand the deformation caused by normal play better than regular vinyl [31] 180 g vinyl is more expensive to produce only because it uses more vinyl. Manufacturing processes are identical regardless of weight. In fact, pressing lightweight records requires more care.
Since most vinyl records contain up to thirty per cent recycled vinyl, impurities can be accumulated in the record, causing a brand new album to have audio artifacts like clicks and pops. Virgin vinyl means that the album is not from recycled plastic, and will theoretically be devoid of these impurities. In practice, this depends on the manufacturer's quality control.
The orange peel effect on vinyl records is caused by worn molds. Rather than having the proper mirror-like finish, the surface of the record will have what looks like an orange peel texture. This introduces noise into the record, particularly in the lower frequency range. It should be noted that with direct metal mastering (DMM) the master disc is cut on a copper-coated disc which can also have a minor "orange peel" effect on the disc itself. As this "orange peel" originates in the master rather than being introduced in the pressing stage, there is no ill-effect as there is no physical distortion of the groove.
While all vinyl records are pressed from metal discs known as 'stampers', a technique known as lathe-cutting is used to create the original discs. A lathe is used to cut microgrooves into an aluminum disc coated with nitro-cellulose lacquer. This lacquer disc is then electroplated with nickel to form a negative known as a 'master' disc, which has a protrusion rather than a groove. The lacquer disc is destroyed when the nickel impression is separated. This master disc is then electroplated with nickel to form a positive disc known as a 'mother'. Many mothers can be grown from a single master before the master deteriorates beyond use. In their own turn the mothers are nickel plated to produce more negative discs known as 'stampers'. Again a single mother can grow many stampers before they deteriorate beyond use. It is these stampers that are then used to mold the final vinyl discs.[32] In this way several million vinyl discs can be produced from a single lacquer original. For production of discs where a relatively small quantity is required, the first nickel negative grown from the lacquer original can be used as a stamper. Production by this latter process (known as the 'one-step-process') is limited to a few hundred vinyl discs or more if the stamper holds out and the quality of the vinyl is high.
Vinyl records do not break easily, but the soft material is easily scratched. Vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops. In extreme cases, they can cause the needle to skip over a series of grooves, or worse yet, cause the needle to skip backwards, creating a "locked groove" that repeats over and over. Locked grooves were not uncommon and were even heard occasionally in broadcasts.
Vinyl records can be warped by heat, improper storage, or manufacturing defects such as excessively tight plastic shrinkwrap on the album cover. A small degree of warp was common, and allowing for it was part of the art of turntable and tonearm design. "Wow" (once-per-revolution pitch variation) could result from warp, or from a spindle hole that was not precisely centered. Standard practice for LPs, which were more expensive than singles, was to include the LP in a plastic lined inner cover. This, if placed within the outer cardboard cover so that the opening was entirely within the outer cover, was said to reduce ingress of dust onto the record surface. Singles, with rare exceptions, had simple paper covers with no inner cover.
There is controversy about the relative quality of CD sound and LP sound when the latter is heard under the very best conditions (see Analog vs. Digital sound argument).
A further limitation of the record is that with a constant rotational speed, the quality of the sound may differ across the width of the record because the inner groove modulations are more compressed than those of the outer tracks. The result is that inner tracks have distortion that can be noticeable at higher recording levels.
7-inch singles were typically poorer quality for a variety of the reasons mentioned above, and in the 1970s the 12-inch single (sometimes referred to as a "doughnut"), manufactured at both 33⅓ and 45 rpm, became popular for DJ use and for fans and collectors.
Another problem arises because of the geometry of the tonearm. Master recordings are cut on a recording lathe where a sapphire stylus moves radially across the blank, suspended on a straight track and driven by a lead screw. Most turntables use a pivoting tonearm, introducing side forces and pitch and azimuth errors, and thus distortion in the playback signal. Various mechanisms were devised in attempts to compensate, with varying degrees of success.