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Subject: Bell Labs


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Original Message 1/17             17-Mar-05  @  11:25 AM   -   Bell Labs

Janet

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Hello all, this is my first time on Dancetech, seems like a really cool site. Do any of you guys know much about Bell Labs and what effect they have had on digital audio systems and the digital audio industry today in general. I managed to find their website but couldn't find many other sites that gave information about them. I am looking for sites, reviews, articles or information in general as I am putting together some research. Any help would be a bonus.

Thank you guys

J

oh and great site



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Message 2/17             17-Mar-05  @  11:49 AM     Edit: 17-Mar-05  |  11:54 AM   -   RE: Bell Labs

beds

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daisy, daisy, give me your answer do

i'm half crazy all for the love of you


there you go, you can talk about a classic film in your homework.

(no clues if you can't work it out, 2 points if you do )



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Message 3/17             17-Mar-05  @  12:33 PM   -   RE: Bell Labs

Janet

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Message 4/17             17-Mar-05  @  12:34 PM   -   RE: Bell Labs

Janet

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Ahh the text to speeh converter, excellent. thanks



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Message 5/17             17-Mar-05  @  03:52 PM   -   RE: Bell Labs

beds

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in the early sixties at bell labs max matthews and others programmed a computer to sing daisy. they were also up to other digital music stuff

in '2001: a space odyssey' kubrik used this song for hal to sing as he was going a bit mad



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Message 6/17             17-Mar-05  @  05:02 PM     Edit: 17-Mar-05  |  05:02 PM   -   RE: Bell Labs

k

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the transistor... That's be pretty important  

and Unix



googling reveals:

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The condenser microphone was developed in 1916 by E. C. Wente at Bell Labs. It was improved over the next 10 years and became in 1926 the Western Electric 394-W microphone used to produce the first generation of sound motion pictures.

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The moving-coil, or "dynamic" microphone was developed by W. C. Wente and A. C. Thuras at Bell Labs in the late 1920's, and was patented in 1931. Unlike the ealier condenser design with a fixed plate behind the vibrating diaphragm, this microphone used a wire coil behind the diaphragm that moved with a "velocity" independent of the sound frequency. The sensitivity of the voltage output depended on the resistance, or "impedance" of the moving coil system. A low impedance of 30 ohms allowed transmission over a long cables without loss of quality. The model 618A was unidirectional and the later model 630A was omnidirectional with a frequency response of 30-15,000 Hz


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1925 Bell Labs develops a moving armature lateral cutting system for electrical recording on disk.

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1931 Arthur Keller and associates at Bell Labs in New York experiment with a vertical-lateral stereo disk cutter.


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1931 In April Leopold Stokowski with his Philadelphia Orchestra used the vertical-cut recorder equipped with a new moving coil pickup with sapphire stylus developed at Bell Labs by Arthur C. Keller to improve the dynamic range of cellulose acetate discs pressed from gold-sputtered wax masters. When Stokowski later at Bell Labs in New York City heard the record of a performance of the "Roman Carnival" by Berlioz made on 1st December 1931, he said it was the finest recording he had ever heard

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1933 Snow, Fletcher, and Steinberg at Bell Labs transmit the first inter-city stereo audio program

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Bell Labs had devised an electromechanical device to simulate a single delay experienced on long distant calls. The device used two springs to transmit the delaying signal and four additional springs to dampen and “center” the driver saddle. While the dampening were housed in long tubes filled with oil, one of the springs transmitting the delay signal ended in a short tube which, by varying the amount of oil in the tube, varied the decay time. After modifying the reverb to create many echoes, it was perfect for Hammond’s needs (hammond organs)

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The history of speech synthesis research at Bell Laboratories goes back several decades, actually predating the digital computer. Dudley's "Voder", demonstrated at the 1939 World's fair, was an early analog system that could be played by an expert and made to produce fairly intelligible speechlike sounds. A description of this device can be found in Dennis Klatt's 1987 review article.

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The first computer-generated music was a brief 17-second composition scored in 1957 by Newman Guttman created using the Music I program written by Max Mathews at the Bell Telephone Laboratories in Murray Hill, New Jersey. Other computer-music centers were soon established at Stanford University, Columbia University, and at IRCAM in Paris. Composer James Tenney at Bell Labs wrote programs involving new mathematical forms such as stochastic processes and has continued to produce acoustic and electronic works of unique originality and beauty. John Chowning developed frequency-modulation (FM) methods for generating computer sound, produced many subtle audio illusions of sounds moving in space, and has used classic proportions such as the Golden Section to create unusual sound spectra.

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negative feedback: The act of comparing a fraction of the output signal to the input signal at the input to an amplifier in such a way that the amplifier will keep this fraction of the output signal always exactly the same as the input signal. Negative feedback is of prime importance in designing with opamps and audio power amplifiers. As applied to audio amplifiers, negative feedback is first attributed to Bell Labs scientist Harold S. Black, as described in the Bell Labs Technical Review, 1934 and his monumental 87 page U.S. patent 2,102,671 filed in 1932

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http://homestudio.thing.net/revue/content/bell-labs.html


1915 - AT&T inaugurated the first transcontinental telephone service for San Francisco World's Fair, made possible by the new vacuum tube amplifier developed Arnold's 1914 tube, from Fagen 1975 by Harold D. Arnold at Bell Labs (see Evolution of Bell Labs for the changing names and corporate structure of the Labs). Arnold had been one of the first to recognize the significance of Lee de Forest's audion tube as a way to amplify telephone signals. After John Stone from the Boston Bell Labs arranged a demonstration of the de Forest tube Oct. 30, 1912, Arnold started his amplifier research project. Using a vacuum pump from Germany, he discovered that removing the air from the tube greatly increased the flow of electrons across the grid electrodes. He built the first amplifying vacuum tube Oct. 18, 1913, and began to install the tubes in telephone amplifiers for long line transmission. Arnold also began a long-term research program to improved the quality of telephone sound, "to get an accurate physical description and a measure of the mechanical operation of human ears in such terms that we may relate them directly to our electrical and acoustical instruments..." (Arnold quoted in Fagen 1975 p. 929). Arnold's program marked a new direction in the "Grand System" of Alexander Graham Bell that would lead to a revolution in sound recording.

1916 - Harvey Fletcher joined the Research Division to work with Irving Crandall on hearing and speech, was director of acoustic research 1927-49, built the Western Electric Model 2A hearing aid and a binaural headset in the 1920's, published the widely-read book Speech and Hearing in 1929 that analyzed the characteristics of sound. Fletcher would lead much of the research on binaural, or what later would be called "stereophonic" sound recording, at Bell Labs.

condenser mic from
Physical Review 1917

1916 - E.C. Wente at Bell Labs developed the condenser microphone to translate soundwaves into electrical waves that could be transmitted by the vacuum tube amplifier. His patent 1,333,744 entitled "Telephone Transmitter" was filed December 20, 1916 and granted March 16, 1920. The device used two condenser plates, one of which was a very thin steel diaphragm .002-inch thick, spaced .001-inch from a large backplate. In his 1917 article, Wente explained "The general construction of the transmitter is shown in Fig. 2, from which the principal features are evident. The diaphragm is made of steel, 0.007 cm. in thickness, and is stretched nearly to its elastic limit. The condenser is formed by the plate B and the diaphragm. Since the diaphragm motion is greatest near the center, the voltage generated, which is proportional to C1/C0, will be greatest if the plate is small." This produced a flat response to 15,000 cycles in the lab. Wente continued to improve the microphone.
condenser mic from
Physical Review 1922
In his 1922 article, he explained, "A sectional drawing of the transmitter is shown in Fig. 1. The transmitter differs from the instrument previously described in several essential respects. The diaphragm, A, is made of 0.002 inch (0.0051 cm.) steel and is stretched so that its natural frequency in free air is 7,000 cycles per second. Annular grooves are cut into the face of the back plate, B, to give the diaphragm the desired natural frequency and damping. The length of the air-gap is 0.001 inch (0.0025 cm.). To keep out moisture, the space surrounding the back-plate is sealed off completely from the outside air. A thin rubber diaphragm, C, is provided to keep the pressure on the two sides of the steel diaphragm substantially equal under all conditions of temperature and atmospheric pressure." Wente made more improvements in 1923: "By a change in the dimensions of the film of air and by the substitution of a duralumin for a steel diaphragm in 1923 a condenser microphone was produced which had a sensitivity 100 times as great as that of previous models. This microphone was sufficiently sensitive to permit the pickup of ordinary sounds at a distance without interference from noise voltages generated in the amplifier, whereas the use of the older models under such circumstances would have been impractical." In 1926 this improved model was sold as the Western Electric 394-W microphone for sound motion picture production.


1918 - Henry Egerton patented on Jan. 8 the first balanced-armature loudspeaker driver, based on the 1882 balanced armature telephone patent of Thomas Watson, and used in the Bell Labs No. 540AW speakers developed by N. H. Ricker Oct. 6, 1922.

1921 - The amplifier, microphone, loudspeaker innovations were combined to create the first public address systems. The largest public demonstration of such as system took place on Armistice Day for the national broadcast of the burial of the Unknown Soldier at Arlington Cemetery, heard over 80 loudspeakers linked by telephone lines in New York, San Francisco, and Arlington. By the next year, standardized p.a. systems were introduced.

1923 - Wente developed the light valve in patent 1,638,555 entitled "Translating Devices", filed May 1, 1923 and granted August 9, 1927. This ". . . . relates to translating devices and has for its object to vary the intensity of a beam of light in response to variations in an electric current." Wente placed a pair of stretched conductors forming a closed loop in a strong magnetic field. Alternating electric currents (representing the signal) passing through the conductors caused them to open and close the slit formed between them. A light beam directed through the slit could then be modulated to form a light record on a moving photographic film. This record could be a sound track or picture elements in a transmission system.

1925 - Henry C. Harrison at Bell Labs developed a matched-impedance recorder to improved the frequency range from the previous narrow 250-2,500 cycles range of acoustic recorders to a wider range of 50-6,000 cycles using the condenser mic, tube amp, balanced-armature speaker, and a rubber-line acoustic recorder with a long tapered horn. This system was licensed to the Victor Talking Machine Co. that used it in April to make the first electrical recording of the Philadelphia Orchestra conducted by Leopold Stokowski. The new system was sold in October by Victor as the "Orthophonic" phonograph capable of playing back acoustically-produced and electrically-produced records.


1926 - Wente developed the moving coil speaker, the Western Electric No. 555 Receiver (Horn driver) is described in patent 1,707,545 entitled "Acoustic Device", filed August 4, 1926 and granted April 2, 1929 . . . ." An object of the invention is to receive and transmit sound with high and uniform efficiency over a wide frequency range." Wente employed a moving coil/diaphragm mechanism moving in a strong magnetic field. It was designed to drive a theater horn and was rushed to the August 6 premier of Don Juan. The important feature was a conical plug in front of the diaphragm which shaped the expanding sound passages from an annular opening at the periphery to a circular aperture at the exit where an exponential horn was to be attached. This provided a fairly efficient transfer of sound from driver to horn with good fidelity at levels required in the theater. The development of the "555" receiver is shared with A. L. Thuras who filed on other aspects as described in patent 1,707,544 with simultaneous dates.

1928 - Wente and A. C. Thuras developed a moving coil, or "dynamic," microphone described in patent No. 1,766,473 entitled "Electrodynamic Device" filed May 5, 1928, and granted June 24, 1930. Thuras filed patents 1,847,702 and 1,954,966 and 1,964,606 in 1931 and 1932 for commercial models of this microphone.

1931 - in April, Leopold Stokowski invited Bell Labs to begin sound recording experiments with his Philadelphia Orchestra. After a series of disappointing radio broadcasts by NBC of his orchestra in 1930-31 that failed to achieve the high quality of reproduction Stokowski was seeking, he helped Bell Labs set up a test room at the Academy of Music in Philadelphia. Arthur C. Keller installed a vertical-cut recorder equipped with a new moving coil pickup with sapphire stylus that extended the dynamic range to 10,000 cycles. Surface noise was reduced by coating the wax master with gold film and a layer of electropated copper, and making the duplicate release copies pressed on ceullulose acetate rather than shellac. In December, the first electrical recordings were made and continued throughout the 1931-32 concert season. 125 of these test recordings have been preserved (a limited edition album of these masters was released in 1980 by Bell Labs).


1932 - in March, several test recordings were made at the Academy of Music using two microphones connected to two styli cutting two tracks on the same wax disk. This recording is the earliest stereophonic recording that has survived, although it was not called "stereo" at that time. Keller had apparently made similar dual recordings in New York in 1928 but were lost; Alan Blumlein made his "stereo" recording of Thomas Beecham and the London Philharmonic in January 1934.


1933 - first public stereo transmission over telephone lines of a concert conducted by Alexander Smallens in Philadelphia to an audience in Constitution Hall in Washington, D.C. on April 27, using a 3-channel system of microphones, amplifiers, loudspeakers and telephone lines. The test was a success , but FM would be used for high-fidelity music broadcasting, not telephone lines.


References:
Daniel, Oliver. Stokowski: a Counterpoint of View. New York: Dodd, Mead & Co., 1982.

Fagen, M.D., ed. A History of Engineering and Science in the Bell System: The Early Years (1875-1925). New York: Bell Telephone Laboratories, 1975.

Fox, Barry. "A Hundred Years of Stereo: Fifty of Hi-Fi," New Scientist 92, December 1981, p. 910.

Mabon, Prescott C. Mission Communications: The Story of Bell Laboratories. Murray Hill, NJ: 1975.

McGinn, Robert. "Stokowski and the Bell Telephone Laboratories: Collaboration in the Development of High-Fidelity Sound Reproduction." Technology and Culture 24, January 1983, pp. 38-75.

Millman, S., ed. A History of Engineering and Science in the Bell System: Communications Sciences (1925-1980). New York: AT&T Bell Laboratories, 1984.

Wente, E. C. "The condenser transmitter as a uniformly sensitive instrument for the absolute measurement of sound density," Physical Review 10, 1917, 39-63.

Wente, E. C. "The sensitivity and precision of the electrostatic transmitter for measuring sound densities," Physical Review 17, 1922, 498-503.

Wente, E. C. "Contributions of Telephone Research to Sound Pictures," Bell Telephone Laboratories, New York, October 29, 1935, paper in AT&T Archives.

___________________________________

I had an idea for a script once. It's basically Jaws except when the guys in the boat are going after Jaws, they look around and there's an even bigger Jaws. The guys have to team up with Jaws to get Bigger Jaws.... I call it... Big Jaws!!!



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Message 7/17             17-Mar-05  @  10:44 PM     Edit: 17-Mar-05  |  10:54 PM   -   RE: Bell Labs

Pongoid

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I met Max Matthews not so long ago. He's a really nice guy. Smart as a whip, too. Yeah, Bell's done all kinds of research, not just in making sound, but also in making silence. You can probably find out about some of their noise elimination technologies if you look around a bit. Obviously much of this predates digital sound technologies as well.

Ape



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Message 8/17             18-Mar-05  @  12:30 AM   -   RE: Bell Labs

Janet

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Guys, I can't tell you how helpful all of this was. You really know your stuff. The trouble I have is translating a lot of the stuff from the web as I find there is a lot of factual information but sometimes I think a certain amount of knowledge about the subject is required prior in order to decipher some of the jargon and make good sense of it all. You have helped me very much, thanks a lot.



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Message 9/17             18-Mar-05  @  10:45 AM   -   RE: Bell Labs

k

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so whats' this for Janet?... college thing?

___________________________________

I had an idea for a script once. It's basically Jaws except when the guys in the boat are going after Jaws, they look around and there's an even bigger Jaws. The guys have to team up with Jaws to get Bigger Jaws.... I call it... Big Jaws!!!



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Message 10/17             18-Mar-05  @  10:45 AM   -   RE: Bell Labs

dARKSTATe

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Intersting how different forums react...

It "Janet" had gone on to the SoS forums and asked for them to do her/his homework, they'd have just said "Fuck off and do your own damn study you lazy student twat"...

You guys are just too nice sometimes...



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