![]() | ||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||
| | Concert PitchEstablished by the International Organisation for Standardisation in 1955, the agreed reference frequency of 440 Hz. for the note called middle A.
| | ||||
| Science & Engineering Encyclopaedia Version 2.4 © 2001-2010 Dirac Delta Consultants Limited | ||||||