Update: SoniaHelper should be renamed FFTHelper and integrated into unlekkerLib, but that hasn’t happened yet. The best way to use it right now is to download the code examples from the VJ workshop I did at Cimatics 2007. That has the code you need as well as some examples of practical usage.

I’ve put together a hack for normalizing the FFT analysis values produced by Sonia’s LiveInput.getSpectrum(). It looks at the maximum values produced, and scales them according to the most recent maximum values. That way, quiet sections will produce relative differences according to the current maximum value, so that both quiet and loud sections give dynamic results.

It also allows you to dampen the values so that the rate of change in values can be controlled. This can be used to make the values change appropriately according to the quality of the music, making it easier to use them for visuals that match the music.

You initialize SoniaHelper like this:

  // SoniaHelper(int _n, int _nbands,boolean doAvg)
  // Start up Sonia
  LiveInput.start(spectrumLength);

  // ...or start up Ess
  Ess.start(this);
   myChannel=new Channel("hello.aiff");
  myChannel.setupFFT(512);

  // init SoniaHelper
  ffthelper=new SoniaHelper(spectrumLength,32,false);
  ffthelper.setMaxLimits(200,2000);
  damperval=0.1f;
  ffthelper.setDamper(damperval); 

Update SoniaHelper inside draw() by passing spectral values from Sonia or Ess:

void draw() {
  ...
  LiveInput.getSpectrum();
  ffthelper.update(LiveInput.spectrum); 

// Ess equivalent
  myChannel.loadSpectrum();
  ffthelper.update(myChannel.spectrum);

  for(int i=0; i< spectrumLength; i++)
	ellipse(i,height/2,
		100*ffthelper.spectrum[i], 100*ffthelper.spectrum[i]);
  ...
}

See the sample code in the ZIP file for more code examples.

• SoniaHelper_0.1.zip.