Concert pitch, also known as concert tuning or A440, refers to the standard pitch used by musicians and orchestras around the world. It is defined as the pitch at which the note A above middle C vibrates at a frequency of 440 Hz.
Concert pitch is important because it allows musicians from different places and times to play together in harmony. When all instruments are tuned to the same pitch, they can create a cohesive sound that is pleasing to the ear.
Before the standardization of concert pitch, musicians tuned to a variety of pitches depending on the region and time period. This made it difficult for musicians to play together and required constant retuning of instruments.
Today, A440 is the most commonly used concert pitch, although some orchestras and musicians may use a slightly different tuning.