A 음의 진동수가 어떻게 바뀌었는지 알아보자

A 음 진동수 440Hz는 자연법칙도 아니고 신이 정해준것도 아니고
관련협회들이 제.정.한것이다

절대음감은 없는거지.

1640 Vienna Franciscan Organ A457.6
1699 Paris Opera A404
1711 John Shore's tuning fork, a pitch of A423.5 He invented the tuning fork, one of which still exists today.
1780 Stines, for Mozart, A421
1780 Organ builder Schulz A421.3
1714 Strasbourg Cathedral organ A391
1722 Dresden's chief Roman Catholic church organ A415
1759 Trinity College Cambridge organ A309
1762 Stringed instruments at Hamburg A405
1772 Gottfried Silbermann built the organ in the main Roman Catholic church in Dresden, and it had a pitch of A 415 at the time.
1780 Organ builder Schulz A421.3
1780 Stein's tuning fork A422.6
1751 Handel's own fork A422.5
1800 Broadwood's C fork, 505.7, which is about half a semitone lower than that of today
1811 Paris Grand Opera A 427
1812 Paris Conservatoire A440, as modern pitch
1813 George Smart adopted for the Philharmonic Society the pitch of A423.3.
1820 Westminster Abbey organ and possibly Paris Comic Opera used a pitch of A422.5.
1828 Philharmonic Society A 440
1834 Vienna Opera A 436.5
1835 Wolfels piano maker A443
1836 Pleyel's Pianos A446
1846 Philharmonic pitch was A452.5 (very high) which lasted till 1854
1846 Mr Hipkins piano tuner (Meantone) A433.5 (Equal) A436.0
1849 Broadwood's medium pitch was A445.9 which lasted till 1854
1858 New Philharmonic pitch C522
1860 Cramer's piano makers of London A448.4
1862 Dresden Opera A 440
1871 Covent Garden Opera House A 440
1877 Collard's piano maker standard pitch was A 449.9
1877 St. Paul Cathedral organ A446.6
1877 Chappell Pianos A455.9
1877 Mr Hipkins piano tuner A448.8
1878 Her Majesty's Organ A436.1
1878 Vienna Opera A447
1879 Covent Garden Opera A450
1879 Erard's factory fork 455.3
1879 Steinway of England A 454.
1879 British Army regulation pitch for woodwinds A451.9
1880 Brinsmead, Broadwood, and Erard apparently used a pitch of A455.3
1880 Steinway may have been using a pitch of A436. According to Steinway of New York, 1880 is right around the time they switched from three piece rims to the continuous rim that is used today. So it is unlikely the pitch was any higher before 1880, yet Steinway of London had a fork A454.7.
1885 In Vienna a pitch of A435.4 was adopted at a temperature of 59 degrees Fahrenheit for A.
1885 At an international exhibition of inventions and music in London a pitch of A452 was adopted.
1896 Philharmonic pitch A439, giving C522
1925 On the 11th of June the American music industry adopted A440.
1936 American Standards Association adopted A440.
1939 At an international conference A440 was adopted.

(출처 : http://www.uk-piano.org/history/pitch.html)