By: wray

wray — Mon, 20 Apr 2009 18:18:20 +0000

I was curious if this is the sort of thing that needs to be implemented so that I can play a sound slower than it is meant to be played — like a record player. I’ll see if I can figure it out……

By: pietro

pietro — Tue, 24 Mar 2009 20:55:38 +0000

yes, it would be nice to have the possibility to do FM in minim.
I’m teaching electronic music and I would love to use processing and minim in a more extensive way, but it is not always possible.
I got stuck in a main problem: I can “get” the samples of any audio buffer into an array, but I don’t know how to “write” a processed array into a buffer in an easy way.
This does neither allow a straightforward implementation of FM or AM algorithms nor a basic thing such as the modulation of the amplitude of a signal by an amplitude envelope.

…really hope that I will be able to use more processing and minim for my electronic music course! It’s a great environment.

here it is an implementation of the AM algorithm (actually a simple ring modulator) done as an AudioEffect:

class Amplitude_Modulation implements AudioEffect
{ // the mono version doesn’t do anything
void process(float[] samp)
{
float[] AM = new float[samp.length];

for (int j = 0; j < samp.length; j++) AM[j] = samp[j];

// we have to copy the values back into samp for this to work
arraycopy(AM, samp);
}

void process(float[] samp1, float[] samp2)
{
float[] AM = new float[samp1.length];

for (int j = 0; j < samp1.length; j++) AM[j] = samp1[j]*samp2[j];
// we have to copy the values back into samp for this to work
arraycopy(AM, samp1);
arraycopy(AM, samp2);
}
}

///////////////////////////////////////////////////////////////////////////////

import ddf.minim.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;

Minim minim;

AudioOutput out1;

SineWave sine1;
SineWave sine2;

Amplitude_Modulation AM;

void setup()
{
size(512, 200, P3D);

minim = new Minim(this);
// try changing the buffer size to see how it changes the effect
out1 = minim.getLineOut();

AM = new Amplitude_Modulation();

sine1 = new SineWave(400, 0.4, out1.sampleRate());
sine1.setPan(1);
sine2 = new SineWave(50, 0.4, out1.sampleRate());
sine2.setPan(-1);

out1.addSignal(sine1);
out1.addSignal(sine2);
out1.addEffect(AM);

}

Comments on: Frequency Modulation Is Easy

By: wray

By: pietro