Phonograph: Wikis

  
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Did you know ...


More interesting facts on Phonograph

Include this on your site/blog:

Encyclopedia

From Wikipedia, the free encyclopedia

Thomas Edison and his early phonograph
A late 20th-century phonograph console and record

The record player, phonograph or gramophone was the most common device for playing recorded sound from the late 1870s until the late 1980s.

Contents

Terminology

Usage of these terms is not uniform across the English-speaking world (see below). In more modern usage, this device is often called a turntable, record player, or record changer. When used in conjunction with a mixer as part of a DJ set up, they are often called decks.

The famous phonograph was the fourth device for recording and replaying sound. The term phonograph ("sound writer") is derived from the Greek words φωνή (meaning "sound" or "voice" and transliterated as phonē) and γραφή (meaning "writing" and transliterated as graphē). Similar related terms gramophone and graphophone have similar root meanings. The coinage, particularly the use of the -graph root, may have been influenced by the then-existing words phonographic and phonography, which referred to a system of phonetic shorthand; in 1852 The New York Times carried an advertisement for "Professor Webster's phonographic class", and in 1859 the New York State Teachers' Association tabled a motion to "employ a phonographic recorder" to record its meetings.

F. B. Fenby was the original author of the word. An inventor in Worcester, Massachusetts, he was granted a patent in 1863 for an unsuccessful device called the "Electro-Magnetic Phonograph".[1] His concept detailed a system that would record a sequence of keyboard strokes onto paper tape. Although no model or workable device was ever made, it is often seen as a link to the concept of punched paper for player piano rolls (1880s), as well as Herman Hollerith's punch card tabulator (used in the 1890 United States census), a distant precursor of the modern computer[citation needed].

Arguably, any device used to record sound or reproduce recorded sound could be called a type of "phonograph", but in common practice it has come to mean historic technologies of sound recording.

In the late 19th and early 20th century, the alternative term talking machine was sometimes used. This term was more in line with Thomas Edison's early view that his invention was better suited for spoken recordings such as dictation than for musical recordings.

United Kingdom

In British English, gramophone came to refer to any sound reproducing machine using disc records, as disc records were popularized in the UK by the Gramophone Company. The term phonograph is usually restricted to devices playing cylinder records. The term gramophone would generally be taken to refer to a wind-up machine, and from the 1960s onwards the more common term would be record player or turntable as part of a system that also played cassettes and included radio. Such a system would be called a hi-fi or stereo (most systems being stereophonic by the mid-1960s).

United States

In American English, phonograph was the most common generic term for any early sound reproducing machine, until the second half of the 20th century, when it became archaic and record player became the universal term for disc record machines. In contemporary American usage phonograph most usually refers to disc record machines or turntables, the most common type of analogue recording from the 1910s on.

Gramophone was a U.S. brand name, and as such in the same category as Victrola, Zon-O-Phone, Graphophone and Grafonola referring to specific brands of sound reproducing machines. (Similarly, in German, das Grammophon (literally "the Gramophone") was the most common generic term for any sound reproducer using grooved records, hence the brand name Deutsche Grammophon.) Emile Berliner's Gramophone was considered a type of phonograph.

The brand name Gramophone was not used in the USA after 1901, and the word fell out of use there, though it has survived in its nickname form, Grammy, as the title of the Grammy Awards. The Grammy trophy itself is a small rendering of a gramophone, resembling a Victor disc machine with a taper arm.

Modern amplifier equipment still labels the input that accepts the output from a modern magnetic pickup cartridge as the "phono" input (abbreviated from "phonograph").

Australia

In Australian English, record player was the term; turntable was a more technical term; gramophone was restricted to the old mechanical (i.e., wind-up) players; and phonograph was used as in British English.

History

Phonautograph

Dictionary illustration of a phonautograph. The barrel is made of plaster of paris.

The earliest known invention of a phonographic recording device was the phonautograph, invented by Frenchman Édouard-Léon Scott de Martinville and patented on March 25, 1857. It could transcribe sound to a visible medium, but had no means to play back the sound after it was recorded. In 2008, phonautograph recordings were for the first time played back as sound by American audio historians, using computers to decode the transcribed waveforms.[2][3]

Phonograph theory

Charles Cross, a French scientist, produced a theory (April 18, 1877) concerning a phonograph, but he did not manufacture a working model. His theory was submitted to the French Academy of Sciences, and was read to the public in December 1877, by which time Edison had produced a working model. Cross and Edison apparently discovered their theories independently.

First phonograph

Patent drawing for Edison's phonograph, May 18, 1880

Thomas Alva Edison conceived the principle of recording and reproducing sound between May and July 1877 as a byproduct of his efforts to "play back" recorded telegraph messages and to automate speech sounds for transmission by telephone.[4] He announced his invention of the first phonograph, a device for recording and replaying sound, on November 21, 1877 (early reports appear in Scientific American and several newspapers in the beginning of November, and an even earlier announcement of Edison working on a 'talking-machine' can be found in the Chicago Daily Tribune on May 9), and he demonstrated the device for the first time on November 29 (it was patented on February 19, 1878 as US Patent 200,521). "In December, 1877, a young man came into the office of the SCIENTIFIC AMERICAN, and placed before the editors a small, simple machine about which very few preliminary remarks were offered. The visitor without any ceremony whatever turned the crank, and to the astonishment of all present the machine said : " Good morning. How do you do? How do you like the phonograph?" The machine thus spoke for itself, and made known the fact that it was the phonograph..."[5]

Edison's early phonographs recorded onto a tinfoil sheet phonograph cylinder using an up-down ("hill-and-dale") motion of the stylus.[6] The tinfoil sheet was wrapped around a grooved cylinder, and the sound was recorded as indentations into the foil. Edison's early patents show that he also considered the idea that sound could be recorded as a spiral onto a disc, but Edison concentrated his efforts on cylinders, since the groove on the outside of a rotating cylinder provides a constant velocity to the stylus in the groove, which Edison considered more "scientifically correct". Edison's patent specified that the audio recording be embossed, and it was not until 1886 that vertically modulated engraved recordings using wax coated cylinders was patented by Chichester Bell and Charles Sumner Tainter. They named their version the Graphophone. Emile Berliner patented his Gramophone in 1887. The Gramophone involved a system of recording using a lateral (back and forth) movement of the stylus as it traced a spiral onto a zinc disc coated with a compound of beeswax in a solution of benzine. The zinc disc was immersed in a bath of chromic acid; this etched the groove into the disc where the stylus had removed the coating, after which the recording could be played.

In May 1889, the first "phonograph parlor" opened in San Francisco. Customers would sit at a desk where they could speak through a tube, and order a selection for one nickel. Through a separate tube connected to a cylinder phonograph in the room below, the selection would then be played. By the mid-1890s, most American cities had at least one phonograph parlor. Another common type of phonograph parlor featured a machine that would start or would be windable when a coin would be inserted. This jukebox-like phonograph was invented by Louis T. Glass and William S. Arnold. Many early machines were of the Edison Class M or Class E type. The Class M had a battery that would break if it fell or was smashed with another object. This would cause dangerous battery acid to spill everywhere. The Class E sold for a lower price and ran on 120V DC.

By 1890, record manufacturers had begun using a rudimentary duplication process to mass-produce their product. While the live performers recorded the master phonograph, up to ten tubes led to blank cylinders in other phonographs. Until this development, each record had to be custom-made. Before long, a more advanced pantograph-based process made it possible to simultaneously produce 90-150 copies of each record. However, as demand for certain records grew, popular artists still needed to re-record and re-re-record their songs. Reportedly, the medium's first major African-American star George Washington Johnson was obliged to perform his “The Laughing Song” (or the separate "Laughing Coon" [1]) literally thousands of times in a studio during his recording career. Sometimes he would sing "The Laughing Song" more than fifty times in a day, at twenty cents per rendition. (The average price of a single cylinder in the mid-1890s was about fifty cents.)

Problems listening to this file? See media help.

Account of inventing the phonograph

Phonograph cabinet built with Edison cement, 1912. The clockwork portion of the phonograph is concealed in the base beneath the statue; the amplifying horn is the shell in behind the human figure.

Edison presented his own account of inventing the phonograph. "I was experimenting," he said, "on an automatic method of recording telegraph messages on a disk of paper laid on a revolving platen, exactly the same as the disk talking-machine of to-day. The platen had a spiral groove on its surface, like the disk. Over this was placed a circular disk of paper; an electromagnet with the embossing point connected to an arm travelled over the disk; and any signals given through the magnets were embossed on the disk of paper. If this disc was removed from the machine and put on a similar machine provided with a contact point, the embossed record would cause the signals to be repeated into another wire. The ordinary speed of telegraphic signals is thirty-five to forty words a minute; but with this machine several hundred words were possible.

"From my experiments on the telephone I knew of how to work a pawl connected to the diaphragm; and this engaging a ratchet-wheel served to give continuous rotation to a pulley. This pulley was connected by a cord to a little paper toy representing a man sawing wood. Hence, if one shouted: ' Mary had a little lamb,' etc., the paper man would start sawing wood. I reached the conclusion that if I could record the movements of the diaphragm properly, I could cause such records to reproduce the original movements imparted to the diaphragm by the voice, and thus succeed in recording and reproducing the human voice.

"Instead of using a disk I designed a little machine using a cylinder provided with grooves around the surface. Over this was to be placed tinfoil, which easily received and recorded the movements of the diaphragm. A sketch was made, and the piece-work price, $18, was marked on the sketch. I was in the habit of marking the price I would pay on each sketch. If the workman lost, I would pay his regular wages; if he made more than the wages, he kept it. The workman who got the sketch was John Kruesi. I didn't have much faith that it would work, expecting that I might possibly hear a word or so that would give hope of a future for the idea. Kruesi, when he had nearly finished it, asked what it was for. I told him I was going to record talking, and then have the machine talk back. He thought it absurd. However, it was finished, the foil was put on; I then shouted 'Mary had a little lamb', etc. I adjusted the reproducer, and the machine reproduced it perfectly. I was never so taken aback in my life. Everybody was astonished. I was always afraid of things that worked the first time. Long experience proved that there were great drawbacks found generally before they could be got commercial; but here was something there was no doubt of."

Oldest surviving recordings

Frank Lambert's lead cylinder recording for an experimental talking clock is often identified as the oldest surviving playable sound recording,[7] although the evidence advanced for its early date is controversial.[8] The phonograph cylinder recordings of Handel's choral music made on June 29, 1888 at The Crystal Palace in London were thought to be the oldest known surviving musical recordings,[9] until the recent playback by a group of American historians of a waveform of "Au Clair de la Lune", recorded on a phonautograph on April 9, 1860.[10] The 1860 phonautogram had not until then been played, as it was only an attempt to transcribe audio waves onto paper.

Disc versus cylinder as a recording medium

Disc recording is inherently neither better nor worse than cylinder recording in potential audio fidelity.

Recordings made on a cylinder remain at a constant linear velocity for the entirety of the recording, while those made on a disc have a higher linear velocity at the outer portion of the groove compared to the inner portion.

Edison's patented recording method recorded with vertical modulations in a groove. Berliner utilized a laterally modulated groove.

A Victor V phonograph ca. 1907

Though Edison's recording technology was better than Berliner's, there were commercial advantages to a disc system since the disc could be easily mass produced by molding and stamping and it required less storage space for a collection of recordings.

Berliner successfully argued that his technology was different enough from Edison's that he did not need to pay royalties on it, which reduced his business expenses.

Through experimentation, in 1892 Berliner began commercial production of his disc records, and "gramophones" or "talking-machines". His "gramophone record" was the first disc record to be offered to the public. They were five inches (12.7 cm) in diameter and recorded on one side only. Seven-inch (17.5 cm) records followed in 1895. Berliner's early records had poor sound quality, however. Work by Eldridge R. Johnson improved the sound fidelity to a point where it was as good as the cylinder.[11] By 1901, ten-inch (25 cm) records were marketed by Johnson and Berliner's Victor Talking Machine Company, and Berliner had sold his interests. By 1908, a majority of the public demanded double-sided disc recordings, and cylinders fell into disfavor. Edison felt the commercial pressure for disc records, and by 1912, though reluctant at first, his movement to disc records was in full swing. This was the Edison Disc Record.

From the mid-1890s until the early 1920s both phonograph cylinder and disc recordings and machines to play them on were widely mass-marketed and sold. The disc system gradually became more popular because of its cheaper price and better marketing by disc record companies. Edison ceased cylinder manufacture in the autumn of 1929, and the history of disc and cylinder rivalry was concluded.

Dominance of the gramophone record

An early 1930s portable wind-up phonograph from His Master's Voice.

Berliner's lateral disc record was the ancestor of the 78 rpm, 45 rpm, 33⅓ rpm, and all other analogue disc records popular for use in sound recording through the 20th century. See gramophone record.

The 1920s brought improved radio technology and radio sales, bringing many phonograph dealers to near financial ruin. With efforts at improved audio fidelity, the big record companies succeeded in keeping business booming through the end of the decade, but the record sales plummeted during the Great Depression, with many companies merging or going out of business.

In 1940, vinyl was used as a record material. Victor apparently pressed some vinyl 78s.

Booms in record sales returned after World War II as standards changed from 78s to vinyl long play records, which could contain an entire symphony, and 45s which usually contained one hit popularized on the radio, plus another song on the back or "flip" side. An "extended play" version of the 45 was also available, designated 45 EP, which provided capacity for longer selections, or two regular-length songs per side.

By the 1960s, cheaper portable record players and record changers which played stacks of records in wooden console cabinets were popular, usually with heavy and crude tonearms. Even pharmacies stocked 45 rpm records at their front counters. Rock music played on 45s became the soundtrack to the 1960s as people bought the same songs that were played free of charge on the radio. Some record players were even tried in automobiles, but were quickly displaced by 8-track and cassette tapes.

High fidelity made great advances during the 1970s, as turntables became very precise instruments with belt or direct drive, jewel-balanced tonearms, some with electronically controlled linear tracking and magnetic cartridges. Some cartridges had frequency response above 30 kHz for use with CD-4 quadraphonic 4 channel sound. A high fidelity component system which cost under $1000 could do a very good job of reproducing very accurate frequency response across the human audible spectrum from 20 Hz to 20,000 Hz with a $200 turntable which would typically have less than 0.05% wow and flutter and very low rumble (low frequency noise). A well-maintained record would have very little surface noise, though it was difficult to keep records completely free from scratches, which produced popping noises. Another characteristic failure mode was groove lock, causing a section of music to repeat, separated by a popping noise. This was so common that a saying was coined: you sound like a broken record, referring to someone who is being annoyingly repetitious.

A novelty variation on the standard format was the use of multiple concentric spirals with different recordings. Thus when the record was played multiple times, different recordings would play seemingly at random.

Records themselves became an art form because of the large surface onto which graphics and books could be printed, and records could be molded into unusual shapes, colors, or with images (picture discs). The turntable remained a common element of home audio systems well after the introduction of other media such as audio tape and even the early years of the compact disc as a lower priced music format. However, even as the cost of producing CDs fell below that of records, CDs would remain a higher priced music format than cassettes or records. Thus, records were not uncommon in home audio systems into the early 1990s.

By the turn of the 21st century, the turntable had become a niche product, as the price of CD players, which reproduce music free from pops and scratches, fell far lower than high fidelity tape players or turntables. Nevertheless, there is some increase in interest as many big-box media stores stock turntables, as do professional DJ equipment stores. On the other hand, all but the most expensive stereo receivers now omit the phono input. The list price of first-run CDs remains above $15, while used records are very inexpensive, and some are rare and sought after. Some combination systems include basic turntables with a CD and radio in retro-styled cabinets. Records also continue to be manufactured and sold today, albeit in very small quantities when compared to the disc phonograph's heyday.

Turntable technology

A Polish made Unitra turntable atop an Electromureș (Unitra-Diora) receiver, circa 1979.

Turntable construction

Inexpensive record players typically used a flanged steel stamping for the turntable structure. A rubber disc would be secured to the top of the stamping to provide traction for the record, as well as a small amount of vibration isolation. The spindle bearing usually consisted of a bronze bushing. The flange on the stamping provided a convenient place to drive the turntable by means of an idler wheel (see below). While light and cheap to manufacture, these mechanisms had low inertia, making motor speed instabilities more pronounced.

Costlier turntables made from heavy aluminium castings have greater balanced mass and inertia, helping minimize vibration at the stylus, and maintaining constant speed without wow or flutter, even if the motor exhibits cogging effects. Like stamped steel turntables, they were topped with rubber. Because of the increased mass, they usually employed ball bearings or roller bearings in the spindle to reduce friction and noise. Most are belt or direct drive, but some use an idler wheel. A specific case was the Swiss "Lenco" drive, which possessed a very heavy turntable coupled via an idler wheel to a long, tapered motor drive shaft. This enabled stepless rotation or speed control on the drive. Because of this feature the Lenco became popular end of the 1950s with dancing schools, because the dancing instructor could lead the dancing exercises at different speeds.

By the early 1980s, some companies started producing very inexpensive turntables that displaced the products of companies like BSR. Commonly found in all-in-one stereos from assorted far-east brands, they used a thin plastic table set in a plastic plinth, no mats, belt drive, weak motors, and often, plastic tonearms with no counterweight. Most used sapphire pickups housed in ceramic cartridges, and they lacked features of earlier units, such as auto-start and record-stacking. While no longer as common now that turntables are absent from the cheap all-in-one stereo, this type has made a resurgence in nostalgia-marketed players.

Turntable drive systems

Many platters have a continuous series of strobe markings machined or printed around their edge. Viewing these markings in artificial light at mains frequency produces a stroboscopic effect, which can be used by the operator to verify rotational speed. Additionally, the edge of the turntable can contain magnetic markings to provide pulses to the electronical speed-control systems.

Idler-wheel drive system

Earlier designs used a rubberized idler-wheel drive system. However, wear and decomposition of the wheel, as well as the direct mechanical coupling to a vibrating motor, introduced low-frequency noise ("rumble") and speed variations ("wow and flutter") into the sound. These systems generally used a synchronous motor which ran at a speed synchronized to the frequency of the AC power supply. Portable record players typically used an inexpensive shaded-pole motor. At the end of the motor shaft there was a stepped driving capstan; to obtain different speeds, the rubber idler wheel was moved to contact different steps of this capstan. The idler was pinched against the bottom or inside edge of the platter to drive it.

Until the 1970s, the idler-wheel drive was the most common on turntables, except for higher-end audiophile models. However, even some higher-end turntables, such as the Lenco, Garrard, EMT, and Dual turntables, used idler-wheel drive.

Belt drive system

In a belt drive turntable the motor is usually located under and to the side of the platter and is connected to the platter by an elastomeric belt. Belt drives brought improved motor and platter isolation compared to idler-wheel designs. Motor noise, generally heard as low-frequency rumble, is greatly reduced.

The design of the belt drive turntable allows for a less expensive motor than the direct-drive turntable to be used. The elastomeric belt absorbs motor vibrations and noise which could otherwise be picked up by the stylus. It also absorbs small, fast speed variations, caused by "cogging", which in other designs are heard as "flutter."

The "Acoustical professional" turntable (earlier marketed under Dutch "Jobo prof") of the 1960s however possessed an expensive German drive motor, the "Pabst Aussenläufer" ("Pabst outrunner"). As this motor name implied, the rotor was on the outside of the motor and acted as a flywheel ahead of the belt-driven turntable itself. In combination with a steel to nylon turntable bearing (with molybdenum disulfide inside for lifelong lubrication) very low wow, flutter and rumble figures were achieved.

Direct drive system

Direct-drive turntables drive the platter directly without utilizing intermediate wheels, belts, or gears as part of a drive train. The platter functions as a motor armature. This requires good engineering, with advanced electronics for acceleration and speed control. Matsushita's Technics division introduced the first commercially successful direct drive platter, model SP10, in 1969 and it was replaced by the Technics SL-1200 turntable, in 1972. Its updated model, SL-1200MK2, released in 1978, had a stronger motor, a convenient pitch control slider for beatmatching and a stylus illuminator, which made it the long standing favourite among disc jockeys (see "Turntablism"). By the beginnings of the 80s, lowering of costs in microcontroller electronics made Direct-Drive turntables more affordable.

Direct vs belt drive

The evaluation of the "best" drive technology is not clear and more depending on the implementation that on the drive technology itself. Technical measurements show that similarly low flutter (0.025% WRMS) and rumble (-78dB weighed) figures are possible for high quality turntables, be belt drive or direct drive.[citation needed]

Pricing

Audiophile grade turntables start at a few hundred dollars and range upwards of $100,000, depending on the complexity and quality of design and manufacture. The common view is that there are diminishing returns with an increase in price - a turntable costing $1,000 would not sound significantly better than a turntable costing $500; nevertheless, there exists a large choice of expensive turntables despite vinyl records being long past their peak in popularity as replay medium.

Pickup systems

Typical magnetic cartridge

Historically, most high-fidelity component systems (preamplifiers or receivers) that accepted input from a phonograph turntable had separate inputs for both ceramic and magnetic cartridges (typically labeled "CER" and "MAG"). One piece systems often had no additional phono inputs at all, regardless of type.

Most systems today, if they accept input from a turntable at all, are configured for use only with magnetic cartridges, with high end systems often having both MM and MC settings.

Piezoelectric (crystal/ceramic) cartridges

See also: Comparison with magnetic cartridges

Early electronic phonographs used a piezo-electric crystal for pickup, where the mechanical movement of the stylus in the groove generates a proportional electrical voltage by creating stress within a crystal (typically Rochelle salt). Crystal pickups are relatively robust, and produce a substantial signal level which requires only a modest amount of further amplification. The output is not very linear however, introducing unwanted distortion. It is difficult to make a crystal pickup suitable for quality stereo reproduction, as the stiff coupling between the crystal and the long styli used prevent close tracking of the needle to the groove modulations. This tends to increase wear on the record, and introduces more distortion. Another problem is with the nature of the crystal itself: it is hygroscopic and tries to absorb moisture from the air and dissolve in it. So it needed protection from the environment by embedding it in other materials, without hindering the movement of the pickup mechanism itself. After a number of years, the protective jelly often deteriorated or leaked from the cartridge case and the full unit needed replacement.

The next development was the ceramic cartridge, a piezoelectric device that used newer, and better, materials. These were more sensitive, and offered greater compliance, that is, lack of resistance to movement and so increased ability to follow the undulations of the groove without gross distorting or jumping out of the groove. Higher compliance meant lower tracking forces and reduced wear to both the disc and stylus. It also allowed ceramic stereo cartridges to be made.

During the 1950s to 1970s, ceramic cartridge became common in low quality phonographs, but better high-fidelity (or "hi-fi") systems used magnetic cartridges, and the availability of low cost magnetic cartridges from the 1970s onwards made ceramic cartridges obsolete for essentially all purposes. At the seeming end of the market lifespan of ceramic cartridges, someone accidentally discovered that by terminating a specific ceramic mono cartridge (the Ronette TX88) not with the prescribed 47 resistance, but with approx. 10 kΩ, it could be connected to the moving magnet (MM) input too. The result, a much smoother frequency curve extended the lifetime for this popular and very cheap type.

Another popular ceramic stereo cartridge was the Audio Technica model AT66, which because of its price performance ratio was favoured by many as an alternative to more expensive magnetic cartridges.

Magnetic cartridges

There are two common designs for magnetic cartridges, moving magnet (MM) and moving coil (MC) (originally called dynamic). Both operate on the same physics principle of electromagnetic induction. The moving magnet type was by far the most common and more robust of the two, though audiophiles often claim that the moving coil system yields higher fidelity sound.

In either type, the stylus itself, usually of diamond, is mounted on a tiny metal strut called a cantilever, which is suspended using a collar of highly compliant plastic. This gives the stylus the freedom to move in any direction. On the other end of the cantilever is mounted a tiny permanent magnet (moving magnet type) or a set of tiny wound coils (moving coil type). The magnet is close to a set of fixed pick-up coils, or the moving coils are held within a magnetic field generated by fixed permanent magnets. In either case, the movement of the stylus as it tracks the grooves of a record causes a fluctuating magnetic field which causes a small electrical current to be induced in the coils. This current closely follows the sound waveform cut into the record, and may be transmitted by wires to an electronic amplifier where it is processed and amplified in order to drive a loudspeaker. Depending upon the amplifier design, a phono-preamp may be necessary.

In most moving magnet designs, the stylus itself is detachable from the rest of the cartridge so it can easily be replaced. There are two primary types of cartridge mounts. The older type is attached using small screws to a headshell which then plugs into the tonearm, while the other is a standardized "P-mount" or "T4P" cartridge (invented by Technics in 1980 and adopted by other manfacturers) that plugs directly into the tonearm. Some mass market turntables use a proprietary integrated cartridge which cannot be upgraded.

An alternative design is the moving iron variation on moving magnet used by Grado, Stanton, and the MMC cartridge of Bang & Olufsen. In these units, the magnet itself sits behind the four coils and magnetises the cores of all four coils. The moving iron cross at the other end of the coils varies the gaps between itself and each of these cores, according to its movements. These variations lead to voltage variations as described above.

Famous brands for magnetic cartridges are: Grado, Stanton/Pickering (681EE/EEE), B&O (MM types for its two, non-compatible generations of parallel arm design), Shure (V15 Type I to V), Audio-Technica, Nagaoka, Ortofon, Technics, Denon and ADC.

Optical readout

A few specialist laser turntables read the groove optically using a laser pickup. Since there is no physical contact with the record, no wear is incurred.

An alternative approach is to take a high-resolution photograph or scan of each side of the record and interpret the image of the grooves using computer software. An amateur attempt using a flatbed scanner lacked satisfactory fidelity[12]. A professional system employed by the Library of Congress produces excellent quality[13].

Styli

Stylus for jukebox using shellac 78 rpm records, 1940s

In the sound recording industry, a stylus is a phonograph or gramophone needle used to play back sound on gramophone records, as well as to record the sound indentations on the master record.

It is a crucial part of the phonograph, as it is the one part of the system that actually contacts the recorded disc and transfers its vibrations to the rest of the system. It is the part which also suffers the greatest wear. There are two desired qualities in a stylus: first, that it faithfully follows the contours of the recorded groove and transfers the vibration to the system, and second, that it does not damage the recorded disc.

Several technologies were used to record the sounds, beginning with wax cylinders.Thomas Edison introduced the use of sapphire in 1892 and the use of diamond in 1910 for the cylinder phonograph. The Edison disc players (1912-1929) never required a stylus to be changed. The harder the material used, the harder the stylus had to be. The latter stylus for vinyl records were also made out of sapphire or diamond. A specific case is the specific stylus type of Bang & Olufsen's (B&O) moving magnet cartridge MMC 20CL, mostly used in parallel arm B&O turntables in the 4002/6000 series. It uses a sapphire stem on which a diamond tip is fixed by a special adhesive. A stylus tip mass as low as 0.3 milligram is the result and full tracking only requires 1 gram of stylus force, reducing record wear even further. Maximum distortion (2nd harmonic) fell below 0.6%.

A wholly different side of this is the shape of needles and styli. The first needles were made of copper or steel and with the extreme forces exerted on them quickly wore out (exchanging them after 2 sides 78 rpm 25 cm, or one side 30 cm were safe choices). Because of this wear, the exact form of the needle hardly received attention. Some needles were made with a bend so a stark backward sloping needle resulted, suggesting (but not offering) lower record and needle wear. Some people even used cactus thorns and accepted loss in high frequency for longer record life. (The Nimbus company also uses thorns when rerecording voices from older 78 rpm disks in their reproduction setup). At the end of acoustic 78 rpm, so-called longplay hardened steel needles came on the market, for 10 sides of a normal 25 cm disk.

When sapphires were introduced for the 78 rpm disk and the LP, they were made by tapering a stem and polishing the end into sphere of around 70 and 25 micrometers respectively. A sphere is not equal to the form of the cutting stylus and by the time diamond needles came to the market, a whole discussion was started on the effect of circular forms moving through a non-circular cut groove. It can be easily shown that vertical, so called "pinching" movements were a result and when the stereophonic LPs were introduced, unwanted vertical modulation was recognized as a problem. Also the needle started its life touching the groove on a very small surface, giving extra wear on the walls.

Another problem is in the tapering along a straight line, while the side of the groove is far from straight. Both problems were attacked together: by polishing the diamond in a certain way that it could be made doubly elliptic. 1) the side was made into one ellipse as seen from behind, meaning the groove touched along a short line and 2) the ellipse form was also polished as seen from above and curvature in the direction of the groove became much smaller than 25 micrometers e.g. 13 micrometers. With this approach a number of irregularities were eliminated. Furthermore, the angle of the stylus which used to be always sloping backwards, was changed into the forward direction, in line with the slope the original cutting stylus possessed. These styli were expensive to produce, but purists accepted these costs all the more, because by now stylus life was much higher than before.

The next development in stylus form came about by the attention to the CD-4 quadraphonic sound modulation process, which requires up to 50 kHz frequency response, with cartridges like Technics EPC-100CMK4 capable of playback on frequencies up to 100 kHz. This requires a stylus with a narrow side radius, such as 5 µm (or 0.2 mil). A narrow-profile elliptical stylus is able to read the higher frequencies (greater than 20 kHz), but at an increased wear, since the contact surface is narrower. For overcoming this problem, the Shibata stylus was invented around 1972 in Japan by Norio Shibata of JVC[14], fitted as standard on quadraphonic cartridges, and marketed as an extra on some high-end cartridges.

The Shibata-designed stylus offers a greater contact surface with the groove, which in turn means less pressure over the vinyl surface and thus less wear. A positive side effect is that the greater contact surface also means the stylus will read sections of the vinyl which were not touched (or "worn") by the common spherical stylus. In a demonstration by JVC [15] records "worn" after 500 plays at a relatively very high 4.5 gf tracking force with a spherical stylus, played "as new" with the Shibata profile.

Other advanced stylus shapes appeared following the same goal of increasing contact surface, improving on the Shibata. Chronologycally: "Hughes" Shibata variant (1975)[16], "Ogura" (1978) [17], Van den Hul (1982) [18]. These styli are marketed as "Hyperelliptical" (Shure), "Alliptic", "Fine Line" (Ortofon), "Line contact" (Audio technica), "Polyhedron", "LAC", and "Stereohedron" (Stanton) [19].

A keel-shaped diamond stylus appeared as a byproduct of the invention of the CED Videodisc. This, together with laser-diamond-cutting technologies, made possible "ridge" shaped stylii such as the Namiki (1985)[20] design , and Fritz Gyger (1989)[21] design. These styli are marketed as "MicroLine" (Audio technica), "Micro-Ridge" (Shure), "Replicant" (Ortofon)[22].

It is important to point out that most of those stylus profiles are still being manufactured and sold, together with the more common spherical and elliptical profiles, despite the CD4 quadraphonic system being a marketing flop.

Equalization

Early "mechanical" gramophones used the stylus to vibrate a diaphragm radiating through a horn. Several serious problems resulted from this:

  • The maximum sound level achievable was quite limited, being limited to the physical amplification effects of the horn,
  • The energy needed to generate such sound levels as were obtainable had to come directly from the stylus tracing the groove. This required very high tracking forces that rapidly wore out both the stylus and the record on lateral cut 78 rpm records.
  • Because bass sounds have a higher amplitude than high frequency sounds (for the same perceived loudness), the space taken in the groove by low frequency sounds needed to be large (limiting playback time per side of the record) to accommodate the bass notes, yet the high frequencies required only tiny variations in the groove, which were easily affected by noise from irregularities (wear, contaminates, etc) in the disk itself.

The introduction of electronic amplification allowed these issues to be addressed. Records are made with boosted high frequencies and/or reduced low frequencies. This reduces the effect of background noise, including clicks or pops, and also conserves the amount of physical space needed for each groove, by reducing the size of the low-frequency undulations.

During playback, the high frequencies must be rescaled to their original, flat frequency response—known as "equalization"—as well as being amplified. A phono input of an amplifier incorporates such equalization as well as amplification to suit the very low level output from a modern cartridge. Most hi-fi amplifiers made between the 1950s and the 1990s and virtually all DJ mixers are so equipped.

The widespread adoption of digital music formats, such as CD or satellite radio, has displaced phonograph records and resulted in phono inputs being omitted in most modern amplifiers. Some newer turntables include built-in preamplifiers to produce line-level outputs. Inexpensive and moderate performance discrete phono preamplifiers with RIAA equalization are available, while high-end audiophile units costing thousands of dollars continue to be available in very small numbers.

Since the late 1950s, almost all phono input stages have used the RIAA equalization standard. Before settling on that standard, there were many different equalizations in use, including EMI, HMV, Columbia, Decca FFRR, NAB, Ortho, BBC transcription, etc. Recordings made using these other equalization schemes will typically sound odd if they are played through a RIAA-equalized preamplifier. High-performance (so-called "multicurve disc") preamps, which include multiple, selectable equalizations, are no longer commonly available. However, some vintage preamps, such as the LEAK varislope series, are still obtainable and can be refurbished. Newer preamplifiers like the Esoteric Sound Re-Equalizer or the K-A-B MK2 Vintage Signal Processor are also available.[23] These kinds of adjustable phono equalizers are used by consumers wishing to play vintage record collections (often the only available recordings of musicians of the time) with the equalization used to make them.

Arm systems

The tone arm (or tonearm) holds the pickup cartridge over the groove, the stylus tracking the groove with the desired force to give the optimal compromise between good tracking and minimizing wear of the stylus and record groove. At its simplest, a tone arm is a pivoted lever, free to move in two axes (vertical and horizontal) with a counterbalance to maintain tracking pressure.

Adjustable counterweight; the dial below is the anti-skating adjustment.

However, the requirements of high-fidelity reproduction place more demands upon the arm design:

  • The tone arm must track the groove without distorting the stylus assembly, so an ideal arm would have no mass, with bearings requiring zero force to move it.
  • The arm should not oscillate following a displacement, so it should either be both light and very stiff, or suitably damped.
  • The arm must not resonate with vibrations induced by the stylus or from the turntable motor or plinth, so it must likewise be heavy enough not to resonate at those frequencies, or it must be damped to absorb vibrations.
  • The arm should maintain a perfect alignment of the cartridge to the tangent of the record groove at any radius from the center and this tangent line should intersect the pivot point of the tone arm.

These demands are contradictory and impossible to realize (massless arms and zero-friction bearings do not exist in the real world), and consequently all tone arm designs are engineering compromises. Solutions vary, but all modern tonearms are at least relatively lightweight and stiff constructions with precision, very low friction pivot bearings in both vertical and horizontal axes. Most arms are made from some kind of alloy (the cheapest being aluminium), but some manufacturers use balsa wood, others use carbon fibers. The latter materials favour a straight arm design, while alloy is easier for producing S-type arms.

Prices vary largely: the well known and extremely popular high-end S-type SME-arm of the 1970-1980 era not only possessed a complicated design, but was also very costly. On the other hand a very cheap arm was made by the now defunct Dutch Jobo/Acoustical firm. This "All balance" arm was only €30,- equivalent. It was used in that period by all official radio stations using the Dutch Broadcast studio facilities of the NOS, as well as by the pirate radio station Veronica. Live disk jockeys lived on this radioship, meaning that the arm had to withstand sudden ship movements. Anecdotal information tells us, that this cheap arm was the only one capable of keeping the needle firmly in the groove, even during heavy storms at sea.

Basic arm design has changed relatively little. S-type tonearms can be found on even the early 1925 Victor Orthophonic Victrola. Though early electrical pickup tonearms were light, their full weight rested on the record. Through to the crystal pickup, this was required to create sufficient tracking force to follow the grooves adequately with relatively stiff styli. Record wear was high. With better technologies (magnetic cartridge), far-smaller tracking forces became possible, and the balanced arm came into use. Most use a counterweight to offset the weight of the arm, cartridge included. A separate spring or small weight provided for finetuning in tracking force. Often, a calibrated dial on the weight provides quick adjustment of stylus force. Stylus forces of 10 to 20 mN (1 to 2 "grams-force", frequently mis-labeled by manufacturers as simply "grams") are typical for modern high-fidelity turntables, while forces of up to 50 mN (5 "grams-force") are common for DJ use. Stanton cartridges of the 681EE(E) series had a small brush attached to it, the weight of which required compensation of both stylus force (1 gram-force extra needed) and anti-skating adjustment values (see next paragraph for its description).

Typical phonograph tonearm

Tonearms are prone to two types of tracking errors that affect the sound. As the tonearm tracks the groove, the stylus exerts a frictional force tangent to the arc of the groove and since this force does not intersect the tone arm pivot, a clockwise rotational force (moment) occurs and a reaction skating force is exerted on the stylus by the record groove wall away from center of the disc. Modern arms provide an anti-skating mechanism, using springs, hanging weights, or magnets to produce an offsetting counter-clockwise force at the pivot, making the net horizontal force on the groove walls near zero. The second error occurs as the arm sweeps in an arc across the disc, causing the angle between the cartridge head and groove to change slightly. A change in angle, albeit small, will have a detrimental effect (especially in stereo) by creating different forces on the two groove walls. Making the arm longer to reduce this angle is a partial solution, but less than ideal, because longer arms weigh more, and because even a long arm won't be long enough since only an infinitely long arm would reduce this error to zero. Some arms (such as the Garrard "Zero" series) have been manufactured with a parallelogram arrangement which pivots the cartridge head on the arm to maintain a constant angle.

If the arm is not pivoted, but instead travels horizontally along a radius of the disc, there is no skating force and no cartridge angle error. Such arms are driven along a linear track using an electronic servomechanism, or a precise mechanical adjustment (the Rabco arm) to position it properly. Rabco developed the first zero tracking error tonearm, followed by Bang & Olufsen with its Beogram 4000 model in 1972. A later development was made by Revox, a Swiss company more widely known for his high end reel to reel tape recorders: they designed a parallel movement using a very short arm moving sideways across the disk under the influence of a special drive motor. The mechanism had to be turned over the disk after its placement and turned back after playing the disk. This was contrary to the Bang & Olufsen design which automatically returned its parallel arm after playing and even detected whether a smaller (and therefore 45 rpm) or a larger (and therefore 33⅓ rpm) disk was present. Only the smaller 33 rpm disks needed a manual speed override.

Early Edison phonographs had used similarly horizontal spring-powered drives to carry the stylus across the record at a pre-determined rate. In practice, the linear tracking system is not widely used today because of its complexity and related expense. However, some of the most sophisticated and expensive systems still employ this technique. It is nearly ideal, as the stylus replicates the motion of the recording lathe when the master recording was cut.

Phonograph in the 21st century

Turntables continue to be manufactured and sold into the 21st century, although in small numbers. While there are many audiophiles who still prefer vinyl records over digital music sources (primarily compact disc) for what they consider superior sound quality, they represent an enthusiastic minority of listeners. The quality of the available record players, tonearms, and cartridges has continued to improve, despite a diminishing market, allowing turntables to remain competitive on the high end audio systems market.

Updated versions of the 1970s era Technics SL-1200 have remained an industry standard for DJs to the present day. Turntables and vinyl records remain popular in mixing (mostly dance-oriented) forms of electronic music, where they allow great latitude for physical manipulation of the music by the DJ.

In hip hop music, the turntable is used as a musical instrument. Manipulation of a record as part of the music rather than for normal playback or mixing, is called turntablism. The basis of turntablism and its best known technique is scratching, pioneered by Grand Wizard Theodore. It was not until Herbie Hancock's "Rockit" in 1983 that the turntablism movement was recognized in popular music outside of a hip hop context.

The laser turntable uses a laser as the pickup instead of a stylus in physical contact with the disk. It was conceived of in the late 1980s, although early prototypes were not of usable audio quality. Practical laser turntables are now being manufactured by ELPJ. They are favoured by record libraries and some audiophiles since they eliminate physical wear completely. Experimentation is in progress in retrieving the audio from old records by scanning the disc and analysing the scanned image, rather than using any sort of turntable.

Although largely replaced since the introduction of the compact disc in 1982, record albums still sell in small numbers and are available through numerous sources. In 2008, LP sales grew by 90% over 2007, with 1.9 million records sold.[24] Many audiophiles believe that all-analogue recordings made using a traditional tape recorder, simple microphone arrays and few overdubs have a more natural sound than digital recordings.[citation needed]

There are also many turntables on the market designed to be plugged into a computer via a USB port for needle dropping purposes.[25]

See also

References

  1. ^ Oliver Read, From Tin Foil to Stereo: Evolution of the Phonograph (1959) 2nd edition 1976: coauthor Walter Welch, Indianapolis: Howard W. Sams & Co., ISBN 0672212064
  2. ^ FirstSounds.org
  3. ^ Jody Rosen (March 27, 2008). "Researchers Play Tune Recorded Before Edison". New York Times. http://www.nytimes.com/2008/03/27/arts/27soun.html. 
  4. ^ Patrick Feaster, "Speech Acoustics and the Keyboard Telephone: Rethinking Edison's Discovery of the Phonograph Principle," ARSC Journal 38:1 (Spring 2007), 10-43; Oliver Berliner and Patrick Feaster, "Letters to the Editor: Rethinking Edison's Discovery of the Phonograph Principle," ARSC Journal 38:2 (Fall 2007), 226-228.
  5. ^ Scientific American July 25, 1896| http://www.machine-history.com/The%20Phonograph.%201877%20thru%201896
  6. ^ Article about Edison and the invention of the phonograph
  7. ^ "Experimental Talking Clock" recording at Tinfoil.com, URL accessed August 14, 2006
  8. ^ Aaron Cramer, Tim Fabrizio, and George Paul, "A Dialogue on 'The Oldest Playable Recording,'" ARSC Journal 33:1 (Spring 2002), 77-84; Patrick Feaster and Stephan Puille, "Dialogue on 'The Oldest Playable Recording' (continued), ARSC Journal 33:2 (Fall 2002), 237-242.
  9. ^ "Very Early Recorded Sound" U.S. National Park Service, URL accessed August 14, 2006
  10. ^ "Researchers Play Tune Recorded Before Edison"
  11. ^ Wallace, Robert (November 17, 1952). "First It Said 'Mary'". LIFE: 87–102. http://books.google.com/books?id=sFIEAAAAMBAJ&source=gbs_navlinks_s. 
  12. ^ Digital Needle - A Virtual Gramophone URL accessed March 31, 2007
  13. ^ You Can Play the Record, but Don't Touch URL accessed April 25, 2008
  14. ^ US Patent 3774918
  15. ^ http://www.johana.com/~johana/dorren/cd-4paper4.pdf
  16. ^ US Patent 3871664
  17. ^ US Pat. 4105212
  18. ^ US Pat. 4365325
  19. ^ http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894&start=0
  20. ^ US Patent 4521877
  21. ^ US Patent 4855989
  22. ^ http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894&start=0
  23. ^ Powell, James R., Jr. and Randall G. Stehle. Playback Equalizer Settings for 78 rpm Recordings. Third Edition. 1993, 2002, 2007, Gramophone Adventures, Portage MI. ISBN 0963492136
  24. ^ Los Angeles Times: Vinyl sales to hit another high point in 2009
  25. ^ USB turntable comparison

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

PHONOGRAPH (Gr. 00)1)17, sound, ypa4 €tv, to write), an instrument for imprinting the vibrations of sound on a moving surface of tinfoil or wax in such a form that the original sounds can be faithfully reproduced by suitable mechanism. Many attempts had been made by earlier experimenters to obtain tracings of the vibrations of bodies emitting sound, such as tuning-forks, membranes, and glass or metallic disks. In 1807 Thomas Young (Lectures, i. 191) described a method of recording the vibrations of a tuning-fork on the surface of a drum; his method was fully carried out by Wilhelm Wertheim in 1842 (Recherches sur l'elasticite, t er mem.). Recording the vibrations of a membrane was first accomplished by Leon Scott in 1857 by the invention of the "phonautograph," which may be regarded as the precursor of the phonograph (Comptes rendus, 53, p. 108). This instrument consisted of a thin membrane to which a delicate lever was attached. The membrane was stretched over the narrow end of an irregularly-shaped funnel or drum, while the end of the lever or marker was brought against the surface of a cylinder covered with paper on which soot had been deposited from a flame of turpentine or camphor. The cylinder was fixed on a fine screw moving horizontally when the cylinder was rotated. The marker thus described a spiral line on the blackened surface. When sounds were transmitted to the membrane and the cylinder was rotated the oscillatithm of the marker were recorded. Thus tracings of vibrations were obtained. This instrument was much improved by Karl Rudolph Kdnig, of Paris, who also made with it many valuable observations. (See Nature, Dec. 26, 1901, p. 184). The mechanism of the recording lever or marker was improved by William Henry Barlow, in 1874, in an instrument called by him the "logograph" (Trans. Roy. Soc., 1874). The next step was Kbnig's invention of manometric flames by which the oscillations of a thin membrane under sound-pressures acted on a small reservoir of gas connected with a flame, and the oscillations were viewed in a rotating rectangular mirror, according to a method devised by Charles Wheatstone: Thus flamepictures of the vibrations of sound were obtained (Pogg. Ann., 1864, cxxii. 242, 660; see also Quelques experiences d'acoustique, Paris, 1882). Clarence Blake in 1876 employed the drumhead of the human ear as a logograph, and thus obtained tracings similar to those made by artificial membranes and disks (Archiv. fiir Ophthalmol., 1876, v. i.). In the same year Sigmund Theodor Stein photographed the vibrations of tuning-forks, violin strings, &c. (Pogg. Ann., 1876, p. 142). Thus from Thomas Young downwards successful efforts had been made to record graphically on moving surfaces the vibrations of sounds, but the sounds so recorded could not be reproduced. This was accomplished by T. A. Edison in 1876, the first patent being dated January 1877.

In the first phonograph a spiral groove was cut on a brass drum fixed on a horizontal screw, so that when the drum Was rotated it moved from right to left, as in the phonautograph. The recorder consisted of a membrane of parchment or gold-beater's skin stretched over the end of a short brass cylinder about 2 in. in diameter. In the centre of the membrane there was a stout steel needle having a chisel-shaped edge, and a stiff bit of steel spring was soldered to the needle near its point, while the other end of the spring was clamped to the edge of the brass cylinder over which the membrane was stretched. The recorder was then so placed beside the large cylinder that the sharp edge of the needle ran in the middle of the spiral groove when the cylinder was rotated. The cylinder was covered with a sheet of soft tinfoil. During rotation of the cylinder, and while the membrane was not vibrating, the sharp edge of the marker indented the tinfoil into the spiral groove; and when the membrane was caused to vibrate by sounds being thrown into the short cylinder by a funnel-shaped opening, the variations of pressure corresponding to each vibration caused the marker to make indentations on the tinfoil in the bottom of the groove. These indentations corresponded to the sound-waves. To reproduce the sounds the recorder was drawn away from the cylinder, and the cylinder was rotated backwards until the recorder was brought to the point at which it started. The cylinder was then rotated forwards so that the point of the recorder ran over the elevations and depressions in the bottom of the groove. These elevations and depressions, corresponding to the variations of pressure of each sound-wave, acted backwards on the membrane through the medium of the marker. The membrane was thus caused to move in the same way as it did when it was made to vibrate by the sound-waves falling upon it, and consequently movements of the same general character but of smaller amplitude were produced, and these reproduced sound-waves. Consequently the sound first given to the phonograph was reproduced with considerable accuracy. In 1878 Fleeming Jenkin and J. A. Ewing amplified the tracings made on this instrument by the sounds of vowels, and submitted the curves so obtained to harmonic analysis. (Trans. Roy. Soc. Edin. xxviii. 745). The marks on the tinfoil were also examined by P. F. F. Gri tzner, Mayer, Graham Bell, A. M. Preece, and Lahr (see The Telephone, the Microphone, and the Phonograph, by count du Moncel, London, 1884;1884; also The Speaking Telephone and Talking Phonograph, by G. B. Prescott, New York, 1878).

The tinfoil phonograph, however, was an imperfect instrument, both as regards the medium on which the imprints were taken (tinfoil) and the general mechanism of the instrument. Many improvements were attempted. From 1877 to 1888 Edison was engaged in working out the details of the wax-cylinder phonograph. In 1885 A. G. Bell and S. Tainter patented the "grapophone," and in 1887, Emile Berliner, a German domiciled in America, patented the "gramophone," wherein the cylinder was coated with lampblack, and the friction between it and the stylus was made uniform for all vibrations. Incidentally it may be mentioned that Charles Cross deposited in 1877 a sealed packet with the Academic des Sciences, Paris, containing a suggestion for reproducing sound from a Scott phonautograph record. The improvements made by Edison consisted chiefly (I) in substituting for tinfoil cylinders or disks made of a waxy substance on which permanent records are taken; (2) in substituting a thin glass plate for the parchment membrane; (3) in improving the mechanical action of the marker; and (4) in driving the drum carrying the wax cylinder at a uniform and rapid speed by an electric motor placed below the instrument.

Missing image
Phonograph-1.jpg

In the first place, permanent records can be taken on the wax, which is composed of stearin and paraffin. This material is brittle, but it readily takes the imprints made by the marker, which is now a tiny bit of sapphire. The marker, when used for recording, is shod with a chisel-shaped edge of sapphire; but the sapphire is rounded when the marker is used for reproducing the sound. The marker also, instead of being a stiff needle coming from the centre of the membrane or glass plate, is now a lever, weighted so as to keep it in contact with the surface of the wax. A single vibration of a pure tone consists of an increase of pressure followed by a diminution of pressure. When the disk of glass is submitted to an increase of pressure the action of the lever is such that, while the wax cylinder is rotating, the point of the marker is angled downwards, and this cuts deeply into the wax; and when there is diminution of pressure the point is angled upwards, so as to act less deeply. In reproducing the sound, the blunt end of the marker runs over all the elevations and depressions in the bottom of the groove cut on the wax cylinder. There is thus increased pressure transmitted upwards to the glass disk when the point runs over an elevation, and less pressure when the point runs over a depre.»ion on the wax cylinder. The glass disk is thus, as it were, pulled inwards and thrust outwards with each vibration, but these pulls ,! Il p p gat: p N FIG. Ia. - Exterior of Edison Phonograph.

and thrusts follow each other so rapidly that the ear takes no cognizance of the difference of phase of the vibrations of the glass plate in imprinting and in reproducing. The variations of pressure are communicated to the glass plate, and these, by the medium of the air, are transmitted to the drum-head of the ear, and the sound is reproduced with remarkable fidelity. It is necessary for accurate reproduction that the point of the marker be in the centre of the groove. In the older phonographs this required accurate adjustment by a fine screw, but in newer forms a certain amount of lateral oscillation is allowed to the marker, by which it slips automatically into the groove. Two other improvements have been effected in the construction of the instrument. A powerful triple-spring motor has been substituted for the electric motor, and the circumference of the wax cylinder has been increased from 68 in. to 15 in., whilst the disk is 12 in. in diameter. The cylinders make about two revolutions per second, so that with the smaller cylinder the point of the marker runs over nearly 14 in. in one second, while with the larger it runs over about 30 in. The marks corresponding to the individual vibrations of tones of high pitch are therefore less likely to be crowded together with the larger cylinder, and these higher tones in particular are more accurately reproduced. In a form of instrument called the 200-thread machine motion of the drum bearing the cylinder was taken off a screw the thread of which was 50 to the inch, and by a system of gearing the grooves on the cylinder were 200 to the inch, or 2 4, of an inch apart. It was somewhat difficult to keep the marker in the grooves when they were so close together; and the movement is now taken directly off a screw the thread of which is loo to the inch, so that the grooves on the cylinder are iozof an inch apart. Thus with the large cylinder a spiral groove of over 300 yds. may be described by the recorder, and with a speed of about two revolutions per second this distance is covered by the marker in about six minutes. By diminishing the speed of revolution, which can be easily done, the time may be considerably lengthened.

In the plate machine the disk is fixed to a table which is rotated at a fixed speed of about 76 revolutions a minute. The speed of the lateral movement of the table is alsc unifcrm, and by a regular progression brings the wax blank under the sound-box to the sapphire cutting point, which detaches a fine unbroken thread of wax as it cuts into the surface of the blank to a depth of 32to 4thousandths of an inch, beginning at about half an inch from the circumference and continuing the spiral groove to within a couple of inches of the centre, according to the length of the music to be recorded. The essential difference between the disk and cylinder machine is that in the former the waves are recorded by horizontal motion over the disk, while in the latter the waves are recorded as indentations.

The following is the modus operandi of making a reccrd. The person making the record sings or plays in front of a horn or funnel used for the purpose of focusing the sound-waves upon the diaphragm. The artist and the funnel are on one side of a screen and the recording apparatus in charge of an operator on the other. The arrangement of the various instruments in the recording room at proper relative distances from the horn is of the utmost importance in order to preserve the balance of tone. At about 4 ft. from the horn are grouped the violins and the wood wind (flutes, oboes and clarinets); behind the brass wind (horns, trumpets, trombones and tubers), and right at the back the violoncellos and double basses and the kettle-drums and other instruments of percussion which may be required. On the other side of the screen is the sound-box and the recording cylinder or disk.

Cylinder records are duplicated by taking a plaster cast, electroplating, and then using it as a matrix. The disk record admits of similar treatment. After dusting with graphite it is electroplated to about '9 mm. thick. This forms the permanent or master record, from which the working negatives are made by taking wax impresses of it and obtaining copper electros in turn from them. The matrix is then nickel-plated and polished and is ready for use in pressing out the commercial records by means of an hydraulic press, the material used being a tough and elastic substance containing shellac and other compounds such as wood charcoal, barium sulphate, earthy colouring matters and cotton flock.

There is still a defect to be overcome in the gramophone, and that is the hissing of the needle produced by friction both during recording and intensified in reproduction. In one device for remedying this the stylus acts like a stylographic pen, depositing on a polished surface a fine stream of some liquid which solidifies and hardens very rapidly, forming a sinuous ridge instead of a groove in a wax blank. A negative is taken of the record and the matrix is made from it in the usual way.

FIG. 1 b. - Mechanism of Edison Phonograph.

Missing image
Phonograph-2.jpg

The auxeto-gramophone or auxetophone, patented by Short in 1898 and improved by the Hon. C. A. Parsons, is similar in scope to the gramophone but attains its results in a different manner. In the Parsons-Short sound-box there is no diaphragm, but a I f 1 ?11?1?!?p? a ,!ilillt111?11I?(?? { Illl i ?f l?I q j I l lll ? 1'111111111111 ' ll lll il 1111111 I Illillilul ? ??Ili l ll h' i column of compressed air is controlled by a delicately adjusted grid-valve consisting of a metal comb rigidly connected to the stylus bar, so that as the needle moves the metal comb moves with it, following the lines of vibration fixed on the record and opening or closing the slots in the valve seat. The column of compressed air to which the valve gives access thus receives series of minute pulsations identical with those which originally produced the sounds recorded. In connexion with the sound-box is the apparatus for supplying compressed air, consisting of a sixth-horse power electric motor driving the compressor, an oil filter, a reservoir and a dust collector to keep the air absolutely free from foreign substances likely to interfere with the action of the valve.

The practical possibilities of the gramophone are being realized in many countries. Matrices of the records of wellknown artists have been deposited at the British Museum and at the Grand Opera in Paris. Austria established a public phonogram record office in 1903, in which are collected folksongs and records of all kinds for enriching the department of ethnography. The same idea is being carried out in Germany FIG. 2.

by private societies and by royal museums. In Hungary records of the various dialects have been secured. The possibilities of the gramophone as a teacher are far-reaching, not only in the domain of music but in learning languages, &c.

To understand how the phonograph records and reproduces musical tones, it is necessary to remember (1) that pitch or frequency depends on the number of vibrations executed by the vibrating body in a given period of time, or on the duration of each vibration; (2) that intensity or loudness depends on the amplitude of the movement of the vibrating body; and (3) that quality, timbre or clang, first, depends on the form of the individual vibrations, or rather on the power the ear possesses of appreciating a simple pendular vibration producing a pure tone, or of decomposing more or less completely a compound vibration into the simple pendular vibrations of which it is composed. If we apply this to the record of the phonograph, we find that, given a constant and sufficiently rapid velocity of the record, a note or tone of a certain pitch will be heard when the marker runs over a number of elevations and depressions corresponding to the frequency of that note. Thus if the note was produced by 200 vibrations per second, and suppose that it lasted in the music for of a second, 20 marks, each made in 2160 of a second, would be imprinted on the wax. Consequently, in reproduction, the marker would run over the 20 marks in of a second, and a tone of that frequency would be reproduced.

The loudness would correspond to the depth of each individual mark on the cylinder or the width on the disk. The greater the depth of a series of successive marks produced by a loud tone, the greater, in reproduction, would be the amplitude of the excursions of the glass disk and the louder would be the tone reproduced. Lastly, the form of the marks corresponding to individual vibrations would determine the quality of the tone or note reproduced, by which we can distinguish the tone of one instrument from another, or the sensation produced by a tone of pure and simple quality, like that from a well-bowed tuning-fork or an open organ pipe, and that given by a trumpet or an orchestra, in which the sounds of many instruments are blended together. When the phonograph records the sound of an orchestra it does not record the tones of each instrument, but it imprints the form of impression corresponding to the very complex sound-wave formed by all the instruments combined. This particular form, infinitely varied, will reproduce backwards, as has been explained, by acting on the glass plate, the particular .9 10 11 12 form of sound-wave corresponding to the sound of the orchestra. Numerous instruments blend their tones to make one wave-form, and when one instrument predominates, or if a human voice is singing to the accompaniment of the orchestra, another form of sound-wave, or rather a complex series of sound waves, is imprinted. When reproduced, the wave-forms again exist in the air as very complex variations of pressure; these act on the drum-head of the human ear, there is transmission to the brain, and there an analysis of the complex sensation takes place, and we distinguish the trombone from the oboe, or the human voice from the violin obbligato.

Missing image
Phonograph-3.jpg

FIG.

3.

Missing image
Phonograph-4.jpg

Many efforts have been made to obtain graphic tracings of wave-forms imprinted on the wax phonograph records. Thus J. G. M`Kendrick took (I) celloidin casts of the surface, and (2) micro photographs of a small portion of the cylinder (Journ. of Anat. and Phys., July 1895). He also devised a phonograph recorder by which the curves were much amplified (Trans. Roy. Soc. Edin., vol. xxxviii.; Proc. Roy. Soc. Edin., 1896-1897, Opening Address; Sound and Speech Waves as revealed by the Phonograph, London, 1897; and Schafer's Physiol., vol. ii., "Vocal Sounds," p. 1229). As already mentioned, so long ago as 1878 Fleeming Jenkin and Ewing had examined the marks on the tinfoil phonograph. Professor Ludimar Hermann, of Konigsberg, took up the subject about 1890, using the wax-cylinder phonograph. He obtained photographs of the curves on the wax cylinder, a beam of light reflected from a small mirror attached to the vibrating disk of the phonograph being allowed to fall on a sensitive plate while the phonograph was slowly travelling. (For references to Hermann's important papers, see Schafer's Physiology, ii. 1222.) Boeke, of Alkmaar, has devised an ingenious and accurate method of obtaining curves from the wax cylinder. He measured by means of a microscope the transverse diameter of the impressions on the surface of the cylinder, on different (generally equidistant) parts of the period, and he infers C' 8 V VD3 16 15 14 from these measurements the depth of the impressions on the same spot, or, in other words, he derives from these measurements the curve of the vibrations of the tone which produced the impression A 0 FIG. 4.

(Archiv. f. d. ges. Physiol. Bonn, Bd. 1, S. 297; also Proc. Roy. Soc. Edin., 1898).

From a communication to the Dutch Otorhinolaryngological Society Dr Boeke has permitted the author to select the accompanying illustrations, which will give the reader a fair conception of the nature of the marks on the wax cylinder produced by various tones. Fig. 2 shows portions of the curves obtained by Hermann, and enlarged by Boeke one and a half times. The numbers i to 4 refer to periods of the vowel A (as in "hard"), sung by Hermann on the notes c e g c'. Numbers 5 to 8 show the curves of the vowel o (as in "go") sung to the same notes. The number of vibrations is also noted. Boeke measured the marks for the same vowels by his method, from the same cylinder, and constructing the curves, found the relative lengths to be the same. In fig. 3 we see the indentations produced by the same vowels, sung by Hermann on the notes c e g c', on the same phonograph cylinder, but delineated by Boeke after his method. The curves are also shown in linear fashion beside each group of indentations. From these measure ments the curves were calculated and reproduced, as in fig. 4. Thus the curves of the same vowel sounds on the same cylinder are shown by two methods, that of Hermann and that of Boeke.

FIG. 5.

Missing image
Phonograph-5.jpg
Missing image
Phonograph-6.jpg

In fig. 5 we see the indentations on the vowel a, sung by Dr Boeke, aged 55, on the notes c d e f g a b c', and near the frequencies of 128, 144, 160, 170.6, 192, 213.3, 240 and 256. The numbers 33 to 40 show the marks produced by the same vowel, sung by his son, aged 13. It will be seen that the boy sang the notes exactly an octave higher. Fig. 6 shows the marks produced by some musical E'S' sounds. Each shows on the right-hand side the curve deduced from the marks, and under it a graphical representation of the results of its harmonic analysis after the theorem of Fourier, in which the ordinates represent the amplitude of the subsequent harmonic constituents. No. 41 is the period of the sound of a pitch-pipe giving a' (425 double vibrations per second), No. 42 the period of a Dutch pitch-pipe, also sounding a' (424.64 double vibrations per second). No. 43 is a record of the period of a sound produced by blowing between two strips of indiarubber to imitate the vocal cords, with a frequency of 453 double vibrations per second. No. 44 is that of a telephone pipe used by Hermann (503 double vibrations per second). Nos. 45 and 46 show the marks of a cornet sounding the notes a of 400 double vibrations per second, and e of 300 double vibrations per second. In fig. 7 are shown a number of vowel curves for the vowels 0, OE, A, E and 1. Each curve has on the right-hand side a graphical representation of its harmonic analysis. The curves are in five vertical columns, having on the A A Jl A 19 18 17 c 21 132 V.D. 22 165 VD. 198 .VD. c' 26¢V.D  ?? n 7e En-54:8h, 6 'A ' French; left-hand side of each drawings, by Boeke's method, of two periods of the marks of the vowel. The marks are shown for the Dutch, German, English and French languages. The sounds of the vowels are o, like o in "go"; oe, like oo in "too"; u, like the German ti in "Fiihrer"; a, like a in "hard"; e, like a in "take"; ij, not in English words, but somewhat like e in "bell"; and i, like ee in "beer." The first section contains only Dutch vowel sounds, either sung or spoken by Boeke or members of his family. The second section contains curves from the voice of Professor Hermann, the third from the voice of the author from a cylinder sent by him to Dr Boeke, and the fourth from the voice of Mons. H. Marichelle, professeur de l'Institut des Sourds-Muets, also forwarded by him to Dr Boeke. Thus curves and marks of the same vowel are shown from the voices of men of four nationalities.

On the construction of the gramophone, see L. N. Reddie, Journ. .Soc. Arts (1908).


<< Phonetics

Phonolite >>


Simple English

The phonograph, or gramophone, was the most common device for playing recorded sound from the 1870s through the 1980s.








Got something to say? Make a comment.
Your name
Your email address
Message