Difference between revisions of "Bark"

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(elaboration of the concept.)
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The bark is the standard unit corresponding to one of the 24 [[critical bands]] representing the width of human hearing system. Human hearing critical bands are narrow at low [[frequency|frequencies]], but become wider at higher [[frequency|frequencies]].
 
The bark is the standard unit corresponding to one of the 24 [[critical bands]] representing the width of human hearing system. Human hearing critical bands are narrow at low [[frequency|frequencies]], but become wider at higher [[frequency|frequencies]].
  
Band Edges:
+
(in Hz) 0, 100, 200, 300, 400, 510, 630, 770, 920, 1080, 1270, 1480, 1720, 2000, 2320, 2700, 3150, 3700, 4400, 5300, 6400, 7700, 9500, 12000, 15500
* 0
+
* 100  
+
* 200  
+
* 300  
+
* 400  
+
* 510  
+
* 630  
+
* 770  
+
* 920  
+
* 1080  
+
* 1270  
+
* 1480  
+
* 1720  
+
* 2000  
+
* 2320
+
* 2700  
+
* 3150
+
* 3700  
+
* 4400  
+
* 5300  
+
* 6400  
+
* 7700  
+
* 9500  
+
* 12000  
+
* 15500
+
  
  
 
converting a ''f'' to it's bark equivalent:  
 
converting a ''f'' to it's bark equivalent:  
  
'''Bark = 13arctan(0.76f / 1000) + 3.5arctan((f / 7500)2)'''  
+
''Bark = 13arctan(0.76f / 1000) + 3.5arctan((f / 7500)2)''  
  
 
[[Image:Cribands.png|none|frame|Figure: Human hearing critical bands versus mp3's 32 equal width subbands]]
 
[[Image:Cribands.png|none|frame|Figure: Human hearing critical bands versus mp3's 32 equal width subbands]]
  
 
Example: Widths of the [[critical band|critical bands]] gets wider towards the higher [[frequency|frequencies]]. [[MP3]]'s 32 equal width [[subband|subbands]] (shown on top) cover the 22.05kHz [[bandwidth]]. The width of 1 [[MP3]] [[subband]] is about 689Hz (32*689=22.05kHz).
 
Example: Widths of the [[critical band|critical bands]] gets wider towards the higher [[frequency|frequencies]]. [[MP3]]'s 32 equal width [[subband|subbands]] (shown on top) cover the 22.05kHz [[bandwidth]]. The width of 1 [[MP3]] [[subband]] is about 689Hz (32*689=22.05kHz).

Revision as of 23:10, 26 November 2005

The bark is the standard unit corresponding to one of the 24 critical bands representing the width of human hearing system. Human hearing critical bands are narrow at low frequencies, but become wider at higher frequencies.

(in Hz) 0, 100, 200, 300, 400, 510, 630, 770, 920, 1080, 1270, 1480, 1720, 2000, 2320, 2700, 3150, 3700, 4400, 5300, 6400, 7700, 9500, 12000, 15500


converting a f to it's bark equivalent:

Bark = 13arctan(0.76f / 1000) + 3.5arctan((f / 7500)2)

Figure: Human hearing critical bands versus mp3's 32 equal width subbands

Example: Widths of the critical bands gets wider towards the higher frequencies. MP3's 32 equal width subbands (shown on top) cover the 22.05kHz bandwidth. The width of 1 MP3 subband is about 689Hz (32*689=22.05kHz).