Information about A440

For other uses, see A-440.

A440 is the 440 Hz tone that serves as the standard for musical pitch. A440 is the musical note A above middle C (A4).

In 1939, an international conference recommended that the A above middle C be tuned to 440 Hz. This standard was taken up by the International Organization for Standardization in 1955 (and was reaffirmed by them in 1975) as ISO 16. Since then it has served as the audio frequency reference for the calibration of pianos, violins, and other musical instruments.

Tuning a piano is an example of a simple frequency calibration that is actually done with the human ear. The piano tuner listens to a standard musical pitch and compares it to the same note on the piano keyboard. The piano is then adjusted (by tightening or loosening strings), until it agrees with the audio standard.

The smallest frequency offset that a piano tuner can hear depends on many factors, including the sound volume, the duration of the tone, the suddenness of the frequency change, and the musical training of the listener. However, the just noticeable difference (for a listener, not the piano tuner) is often defined as 5 cents, where 1 cent is 1/100 of the ratio between two adjacent notes on the piano's keyboard, i.e. 1/100 of an equally tempered semitone.


5 seconds of sine wave at 440 Hz
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note has two primary meanings: 1) a sign used in music to represent the relative duration and pitch of a sound; and 2) a pitched sound itself. Notes are the "atoms" of much Western music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis
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La or A is the sixth note (submediant) in the C Major scale. "A" is generally used as a standard for tuning. When the orchestra tunes, the oboe plays an "A" and the rest of the instruments tune to match that pitch.
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Do or C is the first note of the fixed-Do solfege.

In Western music, the expression "middle C" refers to the note "C" (or "Do" in fixed-Do solfege) located exactly between the two staves of the grand staff, quoted as C4 in scientific pitch
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This is a virtual piano with 88 keys tuned to A440, showing the frequencies, in cycles per second (Hz), of each note (i.e. Note frequencies of each note found on a standard piano). This distribution of frequencies is known as equal temperament, i.e.
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19th century - 20th century - 21st century
1900s 1910s 1920s - 1930s - 1940s 1950s 1960s
1936 1937 1938 - 1939 - 1940 1941 1942

Year 1939 (MCMXXXIX
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International Organization for Standardization (Organisation internationale de normalisation), widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations.
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19th century - 20th century - 21st century
1940s 1950s 1960s - 1970s - 1980s 1990s 2000s
1972 1973 1974 - 1975 - 1976 1977 1978

Year 1975 (MCMLXXV
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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piano is a musical instrument played by means of a keyboard. It produces sound by striking steel strings with felt hammers that immediately rebound allowing the string to continue vibrating at its resonance frequency.
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''For the Anne Rice novel, see Violin (novel)

The violin is a bowed string instrument with four strings tuned in perfect fifths. It is the smallest and highest-pitched member of the violin family of string instruments, which also includes the viola and
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piano tuning is the art of making adjustments to the tensions in the strings of a piano so that the instrument is in tune.

Introduction

The meaning of the term in tune
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outer ear is the most external portion of the ear. The outer ear includes the pinnae (also called auricle), the ear canal, and the very most superficial layer of the ear drum (also called the tympanic membrane).
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In psychophysics, a just noticeable difference, customarily abbreviated with lowercase letters as jnd, is the smallest difference in a specified modality of sensory input that is detectable by a human being.
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The cent is a logarithmic unit of measure used for musical intervals. Typically cents are used to measure extremely small intervals, or to compare the sizes of comparable intervals in different tuning systems, and in fact the interval of one cent is much too small to be heard
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An equal temperament is a musical temperament. It is a system of tuning in which every pair of adjacent notes has an identical frequency ratio. Equal temperaments are often intended to approximate some form of just intonation.
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semitone
Inverse major seventh; diminished octave
Name
Other names minor second
or diatonic semitone;
augmented unison
or chromatic semitone
Abbreviation m2; aug1
Size
Semitones 1
Interval class 1

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sine wave or sinusoid is a function that occurs often in mathematics, physics, signal processing, electrical engineering, and many other fields. Its most basic form is:

which describes a wavelike function of time (t) with
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A440

See also

Introduction