Perception of sound: Audible frequency spectrum

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We have mentioned how the the human ear's audible frequencies go from 20 Hz to 20 KHz. Let's now try and label these frequencies to get a better idea of where they belong in the audible spectrum.

Table 2.2. The frequency spectrum 

NameRangeExtension (octave extension)Comments
Subsonic frequencies1 Hz - 20 Hz4 They are not audible by the human ear. They are generated by earthquakes for example, or by large reed organs in churches.
Very low frequencies20 Hz - 40 Hz1 It is the lowest octave audible to the human ear. The bass drum in a drum kit and the low notes on a piano as well as the sound of thunder or air conditioning are within this range.
Low frequencies40 Hz - 160 Hz2Almost all low frequencies in music are within this range.
Middle-low frequencies160 Hz - 315 Hz1The Central (C) note on the piano (261 Hz) is within this range. This range contains many of the sound signal informations that can be potentially altered by poor equalizing.
Middle frequencies315 Hz - 2.5 KHz3The ear's sensitivity is at its highest in this range. This band's sound quality, if taken individually, is similar to that of telephones.
Middle-high frequencies2.5 KHz - 5KHz1 In this range the isophonic curve [Isophonic curves - Equal loudness contours ] has its highest peak and is therefore the range the ear is most sensitive to. To equalize an instrument in this range increases its presence in the mix, bringing it in front of the other sounds (this is true if you want to obtain the opposite too: if you want to hide an out of tune voice you've been forced to keep in your mix because the singer is the record label's boss' friend's cat's son-in-law, remove the frequencies at 3 KHz and drown it in reverb... it'll become a distant, almost metaphysical presence!).
High frequencies5 KHz - 10 KHz1 It is the range in which we perceive the brightness of sounds because it contains many of the harmonics generated by the notes belonging to the previous ranges. The acoustic energy levels are very low here and the consonants 's', 't' and 'c' belong to this range.
Very high frequencies10 KHz - 20KHz1 Even less acoustic energy is found in this range. Only the highest harmonics of certain instruments are here. They are nevertheless important because they confer the indispensable brightess, without which the mix would become dull.

  • posted on 01-02-2015 02:17
    In spite of international "standards," tuning varies by country, type of music and ensemble--by 5 Hz or more, in some cases. Also, pianos have to use "tempered" tuning, which is a kind of compromise among the various keys a pianist may use when playing. A violin or oboe can be perfectly in tune, but not a piano.
  • posted on 28-09-2011 01:33
    2.5KHz - 5KHz : isophonic curve is at it s highest or lowest peak ? already mentioned that 3KHz is resonance freq of the ear canal so basicaly less amplitude in this range is still perceived loud enough competing with other bands right ?
  • posted on 03-08-2010 14:12
    The typo has been fixed. Than you
  • posted on 30-07-2010 20:31
    "the frequency of the middle C note is approximately 261.626 Hz" - wikipedia while on this page it is 216hz

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