1. Tuning Forks and Scientific Measurements:
- In the early 1800s, scientific methods started being used to determine precise musical pitches.
- In 1834, French physicist Joseph Sauveur created a tuning fork that produced a pitch close to 440 cycles per second.
2. Early Pitch Standards:
- In the mid-1800s, different countries had their preferred pitch standards, ranging from approximately 430 cycles to 450 cycles per second.
- For example, the Philharmonic Society of London used A = 428.6 cycles per second, while the Paris Conservatoire used A = 439.2 cycles per second.
3. International Pitch Conference:
- In 1885, an International Pitch Conference was held in Paris to discuss standardizing musical pitch.
- The conference suggested adopting A = 435 cycles per second as the standard, but it was not widely accepted.
4. Influence of Concert Pitch:
- In practice, concert pitch gradually increased throughout the late 19th century, driven by the desire for brighter and louder performances in larger concert halls and theaters.
- Orchestras and instrument manufacturers raised their tuning pitches accordingly.
5. Adoption of A = 440 Hz:
- By the early 20th century, the pitch A = 440 cycles per second (or A440) had become widely used and accepted in many countries.
- This was partly due to the influence of influential musicians, such as violinist and orchestra conductor Henry Wood in England.
6. International Standardization:
- Finally, in 1939, at a meeting of the International Standards Organization (ISO), A440 was formally adopted as the international standard pitch.
- The decision was based on the widespread acceptance of A440 in the musical community and its practical suitability for orchestras, vocalists, and instrument makers.
Since its establishment in 1939, A440 has remained the musical pitch standard, ensuring consistent tuning across different regions and musical genres worldwide.