Difference between revisions of "Bark"

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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]].
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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]].
  
 
''(in Hz) <math>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 </math>''
 
''(in Hz) <math>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 </math>''
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[[Image:Cribands.png|none|frame|Figure: Human hearing critical bands versus Layer 3 32 equal width subbands]]
 
[[Image:Cribands.png|none|frame|Figure: Human hearing critical bands versus Layer 3 32 equal width subbands]]
  
Example: Widths of the [[critical band|critical bands]] gets wider towards the higher [[frequency|frequencies]]. [[MP3]] 32 equal width [[subband|subbands]] (shown on top), based upon PQF filterbank cover the 22.05kHz [[bandwidth]]. The width of 1 [[MP3]] [[subband]] is about 689Hz (32*689=22.05kHz). Both Bark and ERB bilinear transforms are equivalent in representing the critical bands of human auditory system.  
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Example: Widths of the [[critical band|critical bands]] gets wider towards the higher [[frequency|frequencies]]. [[MP3]] 32 equal width [[subband|subbands]] (shown on top), based upon PQF filterbank cover the 22.05kHz [[bandwidth]]. The width of 1 [[MP3]] [[subband]] is about <math>689Hz (32*689=22.05kHz)</math>. Both Bark and ERB bilinear transforms are equivalent in representing the critical bands of human auditory system.  
  
==Additional Reading:==
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==Additional reading:==
  
* [http://citeseer.ist.psu.edu/smith99bark.html Bark and ERB Bilinear Transforms, Julius O. Smith (1999)]
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* [http://citeseer.ist.psu.edu/smith99bark.html Bark and ERB Bilinear Transforms, Julius O. Smith and Johnathen Abel (1999)]
 
* [http://ccrma.stanford.edu/~jos/bbt/Bark_Frequency_Scale.html The Bark Frequency Scale (condensed), Julius O. Smith (2005)]
 
* [http://ccrma.stanford.edu/~jos/bbt/Bark_Frequency_Scale.html The Bark Frequency Scale (condensed), Julius O. Smith (2005)]

Revision as of 00:00, 17 January 2006

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 = 13*\arctan{(0.76f \div 1000)} + 3.5*\arctan{((f \div 7500)^2)}

Figure: Human hearing critical bands versus Layer 3 32 equal width subbands

Example: Widths of the critical bands gets wider towards the higher frequencies. MP3 32 equal width subbands (shown on top), based upon PQF filterbank cover the 22.05kHz bandwidth. The width of 1 MP3 subband is about 689Hz (32*689=22.05kHz). Both Bark and ERB bilinear transforms are equivalent in representing the critical bands of human auditory system.

Additional reading: