Equalizer

Discussion in 'Mac Programming' started by Resister, Apr 23, 2012.

  1. macrumors newbie

    Joined:
    Apr 23, 2012
    #1
    Hello,

    Does anyone know and/or have an example of how to build and equalizer like that in iTunes ? I don't mean a graphical one, I want to make one like this:
    http://hints.macworld.com/images/eq_big.jpg

    Appreciate the help. :D

    Thanks.
     
  2. macrumors 68000

    Joined:
    Mar 29, 2009
    Location:
    USA
    #2
  3. thread starter macrumors newbie

    Joined:
    Apr 23, 2012
    #3
    Yeah, I'm just wanting to know if anyone has any code for the "brains" of it.

    I've read that Apple's AudioUnits would need to be used, but thats a bit above me.
     
  4. macrumors G5

    gnasher729

    Joined:
    Nov 25, 2005
    #4
    A digital equaliser requires some rather complex maths, FFTs, manipulating the frequencies, transforming back, doing everything very carefully to avoid audible glitches, so I think going through the documentation for audio units is your best chance.

    BTW. If you find something in there that allows changing playback speed without changing pitch I would be interested in hearing about that, just out of curiosity.
     
  5. macrumors regular

    Joined:
    Mar 20, 2006
    #5
  6. macrumors regular

    Joined:
    Aug 21, 2011
    Location:
    Stockholm Sweden
    #6
    Free software

    You might want to search for free open software doing audio editing. Reading the source code might help in understanding how the algorithms work. You might also have a starting point for experiments.

    The projects coming to my mind are
    Audacity -- I believe it only runs equalizer in "batch" mode
    Ardour -- source code available

    //gunnar
     
  7. macrumors 603

    Joined:
    Jul 29, 2003
    Location:
    Silicon Valley
    #7
    Core Audio on Mac OS X includes the AUTimePitch Audio Unit.

    On iOS, Dirac reportedly sells a commercial time pitch library.
     
  8. macrumors 603

    Joined:
    Aug 9, 2009
    #8
    Audacity > Effect > Change Tempo
     

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