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A440 (also known as Stuttgart pitch [1]) is the musical pitch corresponding to an audio frequency of 440 Hz, which serves as a tuning standard for the musical note of A above middle C, or A 4 in scientific pitch notation. It is standardized by the International Organization for Standardization as ISO 16.
The reference point between this scale and normal frequency measurement is defined by assigning a perceptual pitch of 1000 mels to a 1000 Hz tone, 40 dB above the listener's threshold. Above about 500 Hz, increasingly large intervals are judged by listeners to produce equal pitch increments.
A440 Play ⓘ. 440 Hz = 4.21 or 4.39. The Bark scale is a psychoacoustical scale proposed by Eberhard Zwicker in 1961. It is named after Heinrich Barkhausen, who proposed the first subjective measurements of loudness. [1] One definition of the term is "a frequency scale on which equal distances correspond with perceptually equal distances.
A number of different units (some only of historical interest) are shown and expressed in terms of the corresponding SI unit. Conversions between units in the metric system are defined by their prefixes (for example, 1 kilogram = 1000 grams, 1 milligram = 0.001 grams) and are thus not listed in this article.
Scientific pitch, also known as philosophical pitch, Sauveur pitch or Verdi tuning, is an absolute concert pitch standard which is based on middle C (C 4) being set to 256 Hz rather than ~ 261.63 Hz, [a] making it ~ 31.77 cents lower than the common A440 pitch standard.
For standard A440 pitch equal temperament, the system begins at a frequency of 16.35160 Hz, which is assigned the value C 0. The octave 0 of the scientific pitch notation is traditionally called the sub-contra octave , and the tone marked C 0 in SPN is written as ,,C or C,, or CCC in traditional systems, such as Helmholtz notation .
The term temporal frequency is used to emphasise that the frequency is characterised by the number of occurrences of a repeating event per unit time. The SI unit of frequency is the hertz (Hz), [4] named after the German physicist Heinrich Hertz by the International Electrotechnical Commission in 1930.
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. [ 1 ] [ a ] The hertz is an SI derived unit whose formal expression in terms of SI base units is s −1 , meaning that one hertz is one per second or the reciprocal of one second . [ 2 ]