A440, also known as the A above "middle C", and further known as the note most commonly associated with 440 hertz was made the international standard for pitch decided upon in 1955 (ISO 16), and was reaffirmed by the same organization in 1975.
http://en.wikipedia.org/wiki/Pitch_(music)
I can't find any reasoning as to why A has always traditionally been used for the pitch standard. Even when the tuning fork was originally invented, an A was chosen as the best tuning note. My best guess is that it is due to the note's alphabetic significance.
It should also be noted that although some orchestras tune to an electronic tone that is calibrated to 440 hertz, many do not. Many orchestras are primarily concerned with whether or not they're in tune with each other, and as such, the entire orchestra (or band) often tune to an Oboe. The oboe cannot change its tuning, so oftentimes the other members of the band tune to it.
One of the primary reasons for an orchestra, or any group for that matter, to tune to A440 is when there is an instrument whose tuning cannot easily be changed, such as a piano, or organ with a fixed tuning to A440.
Currently in America it is set at A=440, however, some European orchestra like to go a little higher anywhere from 442-5 but in music history A has ranged anywhere from 425-460 if not a wider range of variance
Traditionally, the Concertmaster (usually the first chair violinist) tunes his violin to a known standard pitch like A-440 and then the other orchestral instruments tune to his or her pitch. Sometimes, an oboist provides the pitch tone for tuning. The oboe is used more frequently because its sound penetrates easier to all players of the orchestra.
A standard symphony orchestra can tune to three different members: the principal oboe, the concertmaster, or the solo pianist. The oboist is used to tune whenever there is an oboe in the orchestra, the concertmaster is used whenever there isn't an oboe, and the pianist/keyboardist will play the tuning note if he or she is the soloist for the evening.
Generally a "work" or "piece". The word "song" is never used to describe an orchestral work performed by an orchestra. "Song" is something the Beatles sing.
a above the middle C
Usually a pitchfork tuned to A (440 Hz). In an Orchestra the insturments will all tune to the lead violinist or the piano
Currently in America it is set at A=440, however, some European orchestra like to go a little higher anywhere from 442-5 but in music history A has ranged anywhere from 425-460 if not a wider range of variance
Traditionally, the Concertmaster (usually the first chair violinist) tunes his violin to a known standard pitch like A-440 and then the other orchestral instruments tune to his or her pitch. Sometimes, an oboist provides the pitch tone for tuning. The oboe is used more frequently because its sound penetrates easier to all players of the orchestra.
Right before a performance, they tune their instruments. Usually the concertmaster (1st Chair Violinist) plays A-440, and then a oboist plays the note and the rest of the orchestra tunes to that instrument. The oboe is used because its sound is unique and can be heard better than the violin tone. A-440 (concert A) is sometimes varied a couple cents sharp by some conductors, which is their prerogative to do so. Some go as high as A-446, which produces a much brighter sound.
440 Hertz is the standard frequency used for tuning musical instruments. It serves as a reference point for musicians to ensure that their instruments are in tune with each other.
A standard symphony orchestra can tune to three different members: the principal oboe, the concertmaster, or the solo pianist. The oboist is used to tune whenever there is an oboe in the orchestra, the concertmaster is used whenever there isn't an oboe, and the pianist/keyboardist will play the tuning note if he or she is the soloist for the evening.
Could be a symphony, sonata, or most any other imaginable title. Not really called a tune or song, but rather a Composition.
Generally a "work" or "piece". The word "song" is never used to describe an orchestral work performed by an orchestra. "Song" is something the Beatles sing.
a above the middle C
You want to tune a guitar's 'A' string to 440 hz.
440
The Simpsons theme tune is a really good orchestra piece.