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U.S. Reigns in Audio

04-11-19

Did you know ..

.. FM Radio was invented by an American engineer, Edwin Armstrong, a native of New York City and graduate from Columbia University with a degree in electrical engineering.  Born in 1890, Armstrong came from the Chelsea district of New York City where he was the oldest of three children of John and Emily Armstrong.  John Armstrong worked at the American branch of the Oxford University Press which published bibles and classical works where he later become vice president, and Emily was active in church functions with strong ties to Chelsea.

From an early age, Edwin Armstrong took an interest in mechanical and electrical devices, especially trains.  In 1917 during World War I, Edwin joined the U.S. Army Signal Corps and helped create a communications network for the army in France.

Armstrong was credited for a number electrical engineering achievements including the superheterodyne circuit, still used in radios today.  This circuit made radios more sensitive and selective with the key feature of mixing an incoming radio signal with a locally generated different frequency signal, typically referred to as a mixer.

However, the invention that we know and appreciate the most is FM Radio, which has less static than AM radio.  Armstrong received his first patent on FM in 1933 and shared his invention with the public in 1936 when he gave a demonstration at the offices of the Federal Communications Commission.  He played a music record over AM radio, and then switched it to FM.  It was remarked that it sounded as if the performing orchestra were in the same room. This changed radio forever.

Early radio communication that used amplitude modulation (AM) were bedeviled by the many sources of static interference including electrical equipment and thunderstorms. Armstrong decided to approach the issue differently and encode the radio signal by varying the frequency instead.  This is known as frequency modulation (FM).  Later, Armstrong implemented wide-band frequency modulation which earned five U.S. patents, claimed effective for filtering out noise from within the radio receivers themselves due to the vacuum tubes.

Although heavily invested in developing television, RCA in 1940 offered Armstrong one million dollars for his FM patents.  Armstrong refused the offer because he wanted to be fair to the other licensed companies who paid 2% royalties on their sales.  For some reason, RCA retaliated his refusal and claimed they developed their own FM system and encouraged other companies not to pay royalties to Armstrong.  This caused a headlong law suit and years of litigation. It has been speculated that the stress amounting from this incident is what eventually caused Edwin Armstrong’s death in 1954.

.. The phonograph was invented by American born Thomas Alva Edison in 1877.  This was later called the record player in the 1940s.  The invention consisted of a tinfoil sheet wrapped around a rotating cylinder.  A stylus responded to sound vibrations and produced up and down, or hill-and-dale, grooves in the foil.  A second stylus played back the recorded sounds.  The laboratory of Alexander Graham Bell, in Georgetown, Washington DC, made improvements in the 1880s and caused the stylus to move from side-to-side in a zig-zag groove.  Later, Emile Berliner transitioned the phonograph cylinders to flat discs and founded the United States Gramophone Company in 1894.

The disc phonograph record was the dominant recording medium throughout the 20th century.  During the 1980s, the record (or vinyl LP) took a sharp decline due to the introduction of the compact disc.  However, records are still a favorite among audiophiles and underwent a revival in the 2010s.  Many of the original recordings of musicians are reissued on vinyl LP.  Technically, the highest quality recording is produced on vinyl.

.. The inventors of the speaker to first produce an acceptable quality sound were Rice and Kellog, who patented the moving coil cone loudspeaker in 1924 at General Electric, Schenectady, New York.  Chester Rice was born in Massachusetts and educated at The Albany Academy and Harvard College.  Edward Kellog was born in the state of Washington and a graduate of Phillips Academy in Andover, Massachusetts.  The key difference, compared to previous attempts, was the adjustment of mechanical parameters so the fundamental resonance of the moving system is below the frequency where the cone’s radiation impedance becomes uniform.  Beforehand, only roughly distorted sounds were produced and the primitive horn (which doesn’t use electricity) was still preferred over the muffled sound of the early moving coil loudspeakers.

 

                                      
                                                  

Sound systems of the 1970s

This collection of inventions: FM radio, the record player, and the loudspeaker comprise what people often refer to as their “audio system”, or “stereo system” 1.  It may be of some consequence that these inventions, and their inventors, all originated on America soil.  Radio and reproduced audio are present in just about every home, considered a must for those who drive a car, and a popular choice among many as a mobile device.  The sound reproduced in a theater, especially the movie theater, are highly dependent on the sound quality that accompanies and sells a motion picture.  Globally, the music industry generated 51.5 billion dollars in 2018 - and the United States, considered the biggest market - generated nearly 20 billion of those dollars.


1.  The invention of stereo, or binaural sound, was credited to British engineer Alan Blumlein in 1931.