It would be interesting to know why key 'A' on any International standard keyboard instrument is of frequency 440 Hz.
A European Musician and Composer Paul Winter had visited the Egyptian Pyramids. In the 'Kings Chamber', he found that the sound made by hammering the sacred stone called as 'Sacrophagus' was at 440 Hz.
The Pyramids were built in around 3500 BC.
This is the reason that the first note 'A' on the Piano was tuned to 440 Hz. Egyptians were very advanced in Mathematics, Music, and Astronomy, and this frequency may have some spiritual application. If 'A' is at 440 Hz, 'C' comes at 261.6255528 Hz.
Earlier to Paul Winter, various ancient Pianos in old churches in Europe show the key 'C' still playing at 256, 262, 264, 278.4375, and 280 Hz. These differences were unanimously removed in an International Conference held in Europe in 1939 where 'A' was fixed at 440 Hz.
I am very grateful for this website and the enormous wealth of information shared by Dr. Oke!
However, if I may respectfully suggest, I think this article would benefit from some more rigorous research.
To begin with, it was Paul Horn, not Paul Winter, (both are American composers, though trained in the European musical tradition) that recorded his album 'Inside the Great Pyramid' in 1976. In the album's liner notes he said the Kings Chamber was found to be resonant with 438hz.
There has been so much non-sense written online over the past decade about supposed benefits of A=432hz vs A=440, with dubious claims that 432hz was the pitch standard of the ancients. There is no scientific evidence that "ancients" adhered to an absolute musical pitch standard. The concept of an international pitch standard arose in modern times mainly to meet the needs of mass production brought about by the industrial revolution at around the end of the 19th century, and the beginning of the 20th century. This is the reason why A is usually tuned to 440hz on the piano (or any other western musical instrument), not because of the Egyptians!
Before the 20th Century, pianos were really not so common in churches. Organs were very common, and a large church organ often established the pitch standard for it's local village. The pitch of organs and orchestras varied from town to town all over Europe, and later in America. Often there were simultaneously several different reference pitches of 'A' used in any one region for different types of music, one for ecclesiastical music of church organs and choirs, a different pitch for large orchestras, and another for smaller chamber groups.
A.J.Ellis, in his appendix to Helmholtz's book 'On The Sensations of Tone' offers a wealth of information on the topic, and of the tendencies that led to the eventual adoption of A=440 as an international standard.
Table I in section H of appendix XX, 'The History Of Musical Pitch In Europe' on page 495, provides a list of the hundreds of pitches documented as being used for 'A' in Europe between the years of 1361 to 1878, that range from A=373hz all the way up to A=567hz.
https://archive.org/details/onsensationsofto00helmrich/page/494/mode/2up
Still to this day there are many orchestras that tune to A=442hz or even higher.
I have a harmonium from India that was made in the 1990's that was tuned to A=446hz.
It was Paul Horn, not Paul Winter, (both are American musician/composers, trained in the European musical tradition) that recorded his album 'Inside the Great Pyramid' in 1976. In the album's liner notes Mr. Horn said the Kings Chamber was found to be resonant with 438hz. Others have since claimed it to be 117hz. There seems to be no definitive scientific consensus on a specific resonant frequency for the King's Chamber sarcophagus.
A.J.Ellis, in his appendix to Helmholtz's book 'On The Sensations of Tone' offers a wealth of information on the topic that shows the tendencies that led to the eventual adoption of A=440 as an international standard.
https://archive.org/details/onsensationsofto00helmrich/page/494/mode/2up
Table I in section H of appendix XX, on page 495, of 'On The Sensations of Tone', the article titled 'The History Of Musical Pitch In Europe' , provides a list of the hundreds of pitches documented as being used for 'A' in Europe between the years of 1361 to 1878, that range from A=373hz all the way up to A=567hz.
The concept of an international pitch standard arose in modern times mainly to meet the needs of mass production of musical instruments brought about by the industrial revolution, at around the end of the 19th century, and the beginning of the 20th century. This is the reason why A is usually tuned to 440hz on the piano (or any other western musical instrument), not because of the Egyptians!