1906 – The first audio amplifier was invented by Lee De Forest as a form of a triode vacuum tube as this invention was an evolution from the inventor’s prior audio amplifier, the Audion. Unlike the Audion, which has many problems amplifying sound due it only having two elements of amplification, this evolution of the triode consisted of three different elements that make the amplification a little bit easier. This invention was later evolved and edited over many decades.
1910 – The first successfully working pair of headphones was invented by Nathaniel Baldwin in 1910 as was sold to the United States Navy. This invention was an imitation to the ear pieces from telephones that were invented several decades prior, but the first set of headphones didn’t have the best of sound quality as the production of sound was produced by a high sensitivity of amplified current passageways from the coil into the speakers in the headset. The initial usage of the headphone were solely used by the United States Navy, radio and telephone operators.
1919 (October) – The Radio Corporation of America was founded by David Sarnoff and Owen D. Young. This company became one of the key corporations for technological developments and patents invented in the United States as well as different regional inventors representing countries throughout the world. This would include not only patents such as the shelf-checkout system (patented in the 1990s by John C. Goodwin), but many other technological advancements in music and music technology.
1930 – 7 Trios for Three Trautoniums by Paul Hindemith – As Paul Hindemith was one of the primary composers for the instrument, the trautonium is a mechanical keyboard along this like of an electric organ. The trautonium creates sounds by pressing a key on the keyboard of the instrument and a resistor wire would vibrate alongside of a metal plate. Like a piano, dynamics are produced by the pressure placed on the keyboard while vibrato can also be added by slight movements on the wire. Hindemith wrote these seven trios to showcase the sound of the instrument and they have a string-like harmonious ring to them.
1936 – Free Music by Percy Grainger for Theremin – this work comprised of various short pieces written for the theremin. With the first work solely focusing on slides and tonal changes in dynamic contrast. The second focusing on sliding and manipulating tonal centers through chordal structures on the theremin adding and taking away certain notes to build complexity in their chords.
1939 (September) - After the massive rise of Nazi Germany’s leader, Adolf Hitler, the German army’s expanse continued into the invasion of the country Poland. Two days later, countries Great Britain and France declared war on Germany, beginning the Second World War.
1945 (May) - The Axis Powers (comprised primarily of Germany, Italy and Japan) surrender a week following the suicide of their leader, Adolf Hitler, thus ending the Second World War. The conclusion of the war was on May 8th and is known as VE Day (Victory in Europe Day).