How to make "Equalizer" with Processing

joh

(I am japanese…so, if above is not good English, please ask me. I'm using Processing 2.0)

Hi, I am beginner on Processing.

I want to make something like "Equalizer" with Processing. but, I can't understand the meaning of the function fft.getband(int i) getband(int i) method "Returns the amplitude of the requested frequency band. " (Please see http://code.compartmental.net/minim/javadoc/ddf/minim/analysis/FourierTransform.html#getBand(int))

What is the amplitude?

the amplitude changes with fft.timeSize ?

What is the difference with "db" ?

Following is my code.

---

import ddf.minim.spi.*;
import ddf.minim.signals.*;
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.ugens.*;
import ddf.minim.effects.*;


Minim        minim;
AudioPlayer  ap;
FFT          fft;


void setup()
{
  int timeSize = 2048;
  size(1280, 720);
  minim = new Minim(this);
  ap = minim.loadFile("sound_file.mp3", timeSize);
  fft = new FFT(ap.bufferSize(), ap.sampleRate());  
}


void draw()
{
  background(0);
  stroke(255);
  fft.forward(ap.mix);
  ap.play();
  for(int i = 0; i < fft.specSize(); i++)
  {
    float band = fft.getBand(i);
    float vo = height - band * 16;
    line(i + 128, height, i + 128, vo);
    }
  } 
}


void stop()
{
  ap.close();
  minim.stop();  
  super.stop();
}

---

(Please refer "File > Examples > Libraries > minim > AnalyzeSound")

When I change timeSize, the amplitude changes as almost large as timeSize.

How can I make EQ with Processing ? It itn't the best way coding with Processing?

Please help me…