Fig. 326 - The Edison Cylinder.
On April 24, 1878, the "Edison Speaking Phonograph Company" was organized and one of the first innovations introduced was the launching of the phonograph driven by an electric motor. Therefore, at the time of the introduction of the phonograph, others new similar inventons were appearing quickly. Thus, in 1880, Alexander Bell, the inventor of the telephone, supported by his cousin Chichester Bell and professor Charles Sumner Tainter, developed a new method for reproducing natural sound using a jet of compressed air, later described as the “Graphophone” whose patent was granted on May 4, 1886.
Therefore, in spite of the innovation, the new apparatus had difficulties in reproducing the recorded sound due the type of system used for. After many researches, Bell and Tainter developed a wax-coated cardboard cylinder.
Soon Bell and his associates organized the Volta Graphophone Company in order to exploit it for the reproduction of music.
Fig. 327 - The Edison diamond record
Since there were circa seventeen United States patents issued on the behalf of Edison on phonographic devices, in the beginning he understood that a machine on which records of sound were engraved and reproduced from wax-made cylinder substantially seemed similar to his phonograph. However, due to mutual interests involved the two companies decide to merge forces by founding on July 14, 1888 the “North American Phonograph Company”. After some time such a kind of commercial arrangement proved to be unfeasible and soon, it was incorporated a new company under the tradename: “American Graphophone C ompany”, whose pioneering work led to the publication of the first catalog of recorded cylinders.
At the end of XIX century, in spite of the great production of recorded cylinders, they were still priced far beyond the means of most householders.
Thus, such situation led to new developments and around 1908 following the introduction of the standard four-minute wax Amberol record. In order to improve even more the record surface quality, in 1911 the celluloid was used in the cylinder manufacturing, giving birth well-known Blue Amberol cylinder. Fig 326
Therefore, due to several technical and economical aspects, the cylindrical shaped phonogram carved out new trends. In 1913, Edison launched in the market the flat record as known as “Edison diamond record”, that still kept the original vertical recording pattern. Fig 327
Fig. 328 - The early hand-driven gramophone invented by Berliner.

However, a German inventor living in the USA, Emile Berliner, by no means developed the idea of the disc records. Basically his concept consisted in tracing the waveforms of the sound in a spiral, laterally undulating line upon lampback coated glass disc. After many experimentation, in 1888, Berliner did a public presentation of his new recording concept in t he Franklin Institute in Philadelphia, now using a flat metal disc covered with a thin layer of wax; after recording, the wax coated metal disc was immersed in an acid bath, which etched the wavy lines exposed to the solution by recording the desire depth. By a continuous improvement Berliner started to use electropating techniques and soon was able to make stampers by electrotyping from the original record, so the duplicates could be pressed from heated plastic materials in large quantities. For the reproduction the new type of phonogram, Berliner invented a very crude hand-driven machine also, patented under the tradename of “Gramophone”, in order to differentiate it either from the “Edison phonograph” as well as the “Graphophone”. Fig 328
Meanwhile the electrotyping techniques, around 1920, the recordings were still made by mechanical-accoustical methods based in the original Edison phonograph. Thus in the recording studio it was used a resonant device as know as horn, responsible to collect the sound waves, which in turn moved a diafragm-stylus embossing the sound wave patterns on the record.
Fig. 329 -A type of metal stamper or master circa 1950.
Since the diaphragm was the sole source for the whole recording sound frequency spectrum, it had a low accoustical performance, allowing a limited dynamic range no better than 200Hz to 3kHz.
As aforementioned in chapter 7, during the twenties, the microphone developed from the wireless, when allied with the thermionic valve, dramatically changed the idea of sound reproduction by the introduction of the sound tracks into motion pictures and consequently giving birth of the electrical recording, which improving substantially the frequency response, now ranging from 50 Hz to 4 kHz. At this time the new famous recording trade names appeared in the market such as “Vivaltonal”, “Orthophonic”. Around 1930, those recording were made from wax stampers allowing a frequency response up to 10 kHz. Fig. 329
Before the Berliner’s system no stampers were used as the records were made individually, arising several types of irregularities either in the frequency response as well as in the pressing process. Also, the most important factors for a proper sound recording, as the cutting method and recording speed were in their childhood.
Thus, before the gramophone system the records were made using the older phonograph technology by indenting vertically undulating groove of variable depth where the stylus had a hill-and-dale movement.
Afterward the majority of records were made using the horizontal modulation as know as lateral cutting method originally, developed by Berliner.
Fig. 330 - A phonographic record in mid-fifities.
Before the advent of the hysterisis-synchronous motor, used in the cutting machines, and due to the lack of industrial standards as well as a suitable quality control, there were different types of records speeds such as 78-78, 26-80 or even 80 rpm as found in the early Berliner’s discs.
In the beginning of the phonographic industry, Enrico Caruso, the well-known Italian singer, and many crafstmen like Eldridge Jonhson worked hard to improve the uniformity of the disc’s recording and playback speed, whose technical criteria appeared with the electrical recording in the later twenties.
But if the sound recording was still a difficult operation, the pressing was even more complex process since in the early days suitable plastic materials for stamping and molding were not still available in the market.
Originally the first disc were mading using several type of mateirals: hard rubber or “Vulcanite” natural resins like the shellac, and finally the first type phenolic synthetic resin known as “Condensite”. Fig. 330
Based in the manufacturing principles used, the records were supplied in variable thickness as well as in sizes ranging from 10 to 12 inches. In certain labels it was possible to find discs with diameters from 5-1/2 to 20 inches.
As a foreseen the “Gramophone” system revolutionized the phonographic industry by introducing the making of stampers by electrotyping from the original record, so the duplicates could be pressed from heated plastic materials in large quantities.
Therefore, in spite the great sound quality of such manufacturing process it was still impossible to avoid the record surface noisy due to the physical-chemical of such a kind of materials.
Even so in the beginning of the electrical recording era, the phono reproducer, as know as pick up, was still primitive using the old fashion steel needles, without a uniform geometry and in this way arising difficulties to follow the disc grooves pattern. Thus, to overcome such handicap a certain amount of abrasive meadia such as carborundum was mixed in the material of the record for the purpose of making the variable steel needle conform to the groove. Fig 331
Fig. 331 - On the left: several types of needles used for the playback of antique phonographic records. On the right, the acoustical pickup or diaphragm used for the playback of the first “Gramophone” and “Victrola”.
Around 1930, engineers involved with the phonographic industry started searching for high fidelity and long playing recordings.
However, such advanced technological goal was reached in 1948 only, when Dr. Peter Goldmark working at CBS research laboratories invented the micro-groove record.
Fig. 332 - A modern type of pickup. In the first plane and old type of recording pickup made by the German company NORA.
This new recording technique used a new type of pressing material, as known as, “Vinylite”, bringing many advantages when compared with the older count parts. Among them are: long playback time that gave birth of its name - “Long Playing” –, better dynamic range, high fidelity frequency response and the possibility to use low pressure tracking pickups, which improved the disc wear resistance as well as decreasing its surface noisy. Fig 332
The launching of the “Long Playing” record was a great marketing success, but even so the phonographic industry was still facing problems now related with the playback frequency equalization standards which has two main functions: to indicate the characteristics how the recording was made and the sonic correction applied over each specificone.
Around 1950, before the RIAA curve was finally agreed upon as an industry standard, each major record company developed and used is own equalization curve. Thus, in 1953, the “Record Industry Association of America”, developed the equalization curve as known as “RIAA” and was adopted by all leading recording companies as a standard for record reproduction. Fig 333

The equalization curve RIAA - an acronym for Record Industry Association of America - is used to designate the reproduction characteristics adopted by all recording companies. The standard was adopted in June 1953 and reafirmed in March 1964. Such equalized reproduction standards generally were printed in the first "Long Playing" records cover as per hereunder mentioned graph.
Fig 333 - The RIAA equalization curve is shown in the above-mentioned table.

In spite of the excellent sound quality of the new record using micro-groove – Long Playing – the engineers were still in their perenial search for better sound reproduction media. In 1930, several studies conducted either in the USA as well as in England indicated the possibility to develop stereophonic recording. However, soon they were abandoned due to several technical and economical factors involved.
The first stereophonic recordings were launched in the market circa 1956. Considering the large frequency response and high dynamic level, they allowed the recording of the natural sounds with minimum distorsion, true fidelity and an enormous definition enhanced by the stereophonic effect.
Notwithstanding this fantastic technological improvements up to the early sixties all the recording of natural sounds were still made by analogical means.
Type of Recording
Speed - rpm
Time Constants and Threshold Frequencies
Bass Boost
Treble Cut
Older discs:
640 s 250 Hz
Decca ffrr
1060 s 150 Hz
25 s 6400 Hz
350 s 450 Hz
75 s 2100 Hz
530 s 300 Hz
90 s 1800 Hz
Older Long Playing:
Decca LP
33 1/3 - 45
530 s 300 Hz
80 s 2000 Hz
33 1/3 - 45
350 s 450 Hz
75 s 2100 Hz
Columbia LP
33 1/3 - 45
400 s 400 Hz
90 s 1800 Hz
Modern Long Playing
33 1/3 - 45
320 s 500 Hz
75 s 2100 Hz
The threshold frequencies are those at which the response is about 3 dB up or down.
Fig 333-a the equalization requirements for various types of phonographic records between 1935-1954 are shown in the above-mentioned table.

Table 3 – Landmarks in the phonographic disc evolution.
Edison tin foil
Molding material: tin foil, 0,002” in thickness made of a tin/lead alloy.
Main characteristics:
- Groove density: 1-/inch;
- Recording method: vertial with constant - groove speed;
- Speedy: 60 rpm;
- Recording / playback needle: steel made with conical radius 0,016”
- Cylinder diameter: 4,97”
Notes: the til foils was mede by the Crookes method. It consists in rolling the lead / tin foils cladding.

Berliner’s flat disc Molding material: Vulcanite or hard rubber
Main characteristics:
- Speed: 70 rpm;
- Recording method: lateral or horizontal modulation;
- Matrix made by electroplating;
- Many copies available;
- Higher dymanic range;
Notes: In the Berliner recording method, patented under the trade name “Gramophone, the traced waveforms were recorded in the matrix’s grooves by an eletrocchemical process instead of the originally sound energy required in the early discs, which improved substantially the volume of the recording.
Long- playing disc Molding material: synthetic resin – Vynilite
Main characteristics:
- Sound patters recorded in microgrooves
- Speed: 33 1/3 rpm allowing higher recording time;
- Higher dymanic range
- High fidelity fequency response;
- Improved record life;
- Low noisy level;
- Low needle playback pressure;
- Small lneedle radius;
Notes: Dr. Peter Golmark developed the long-playing record at Columbia research laboratories. It allows higher recording data when compared with the forme 78 rpm counterpart.
Stereophonic Long-Playing disc Molding material: Vynil
Main characteristics:
- Frequency reponse: 30-18000 Hz;
- Speed: 33 1/3 rpm;
- Recording method: orthogonal for both channels;
- Disc diameter: 10 and 12”;
- Dymanic range: 45 to 55 dB;
- Equalization: RIAA standard;
- Playback using low needle pressure: 0,5 to 2,0 g;
Notes: High fidelity recording reproduction improved by the stereophonic effect.
Stereophonic Long-Playing disc Molding material: high quality vynil.
Main characteristics:
-F requency response: flat, 0-21 kHz (-3dB at 22 kHz);
- Noisy to signal ratio: 90 dB RMS (non-weighted);
- Flutter: non-measurable;
- Wow: non-measurable;
- Intermodulation distorsion: none;
- Crosstalk: none;
Notes: Basically, it consits to transfer to a master tape the audio signals already converted into numerals, which represents the frequency range in a certain time internval. Thus, recorded sound waveforms could be virtually the same as found in the natural sound source.