What's the simplest way to generate a sine wave sound at any frequency in Java? A sample size more than 2 bytes would help, but it doesn't really matter.
14
votes
7 Answers
11
votes
See Beeper for a self-contained example.
Perhaps something simpler?
That 51 lines of snippet (repeated below - spaced out for single line & in-line comments) as shown at the top of the linked answer, is about as simple as generating a tone gets (OK, you can take out 5+ lines for the harmonic).
People seem to assume it should be a method built into the toolkit to produce a pure tone. It is not, and takes a little calculating to make one.
/** Generates a tone, and assigns it to the Clip. */
public void generateTone()
throws LineUnavailableException {
if ( clip!=null ) {
clip.stop();
clip.close();
} else {
clip = AudioSystem.getClip();
}
boolean addHarmonic = harmonic.isSelected();
int intSR = ((Integer)sampleRate.getSelectedItem()).intValue();
int intFPW = framesPerWavelength.getValue();
float sampleRate = (float)intSR;
// oddly, the sound does not loop well for less than
// around 5 or so, wavelengths
int wavelengths = 20;
byte[] buf = new byte[2*intFPW*wavelengths];
AudioFormat af = new AudioFormat(
sampleRate,
8, // sample size in bits
2, // channels
true, // signed
false // bigendian
);
int maxVol = 127;
for(int i=0; i<intFPW*wavelengths; i++){
double angle = ((float)(i*2)/((float)intFPW))*(Math.PI);
buf[i*2]=getByteValue(angle);
if(addHarmonic) {
buf[(i*2)+1]=getByteValue(2*angle);
} else {
buf[(i*2)+1] = buf[i*2];
}
}
try {
byte[] b = buf;
AudioInputStream ais = new AudioInputStream(
new ByteArrayInputStream(b),
af,
buf.length/2 );
clip.open( ais );
} catch(Exception e) {
e.printStackTrace();
}
}
9
votes
Use the Java Sound API, and Math.sin to create the actual wave levels.
http://www.developer.com/java/other/article.php/2226701 has an excellent tutorial around this that I had referenced some time ago. http://jsresources.org/examples/ was another useful reference.
8
votes
If you want some easy code to get you started, this should help
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.SourceDataLine;
public class SinSynth {
//
protected static final int SAMPLE_RATE = 16 * 1024;
public static byte[] createSinWaveBuffer(double freq, int ms) {
int samples = (int)((ms * SAMPLE_RATE) / 1000);
byte[] output = new byte[samples];
//
double period = (double)SAMPLE_RATE / freq;
for (int i = 0; i < output.length; i++) {
double angle = 2.0 * Math.PI * i / period;
output[i] = (byte)(Math.sin(angle) * 127f); }
return output;
}
public static void main(String[] args) throws LineUnavailableException {
final AudioFormat af = new AudioFormat(SAMPLE_RATE, 8, 1, true, true);
SourceDataLine line = AudioSystem.getSourceDataLine(af);
line.open(af, SAMPLE_RATE);
line.start();
boolean forwardNotBack = true;
for(double freq = 400; freq <= 800;) {
byte [] toneBuffer = createSinWaveBuffer(freq, 50);
int count = line.write(toneBuffer, 0, toneBuffer.length);
if(forwardNotBack) {
freq += 20;
forwardNotBack = false; }
else {
freq -= 10;
forwardNotBack = true;
} }
line.drain();
line.close();
}
}
2
votes
The createSinWaveBuffer() method in these answers does not produce good waveform data for playing continuously. Need to have the last byte be near zero to have a complete waveform. Better example -
protected static final float SAMPLE_RATE = 16 * 1024;
public static byte[] createSinWaveBuffer(double freq) {
double waveLen = 1.0/freq;
int samples = (int) Math.round(waveLen * 5 * SAMPLE_RATE);
byte[] output = new byte[samples];
double period = SAMPLE_RATE / freq;
for (int i = 0; i < output.length; i++) {
double angle = 2.0 * Math.PI * i / period;
output[i] = (byte)(Math.sin(angle) * 127f); }
return output;
}
1
votes
In a first I advice create class Note, which return frequences of note, and convert it to byte array.
Then stream it very easly
protected static final int SAMPLE_RATE = 8 * 1024;
public static void main(String[] args) throws LineUnavailableException {
final AudioFormat af = new AudioFormat(SAMPLE_RATE, 8, 1, true, true);
SourceDataLine line = AudioSystem.getSourceDataLine(af);
line.open(af, SAMPLE_RATE);
line.start();
// fist argument is duration of playing note
byte[] noteDo = Note.DO.getTone(1, SAMPLE_RATE);
byte[] noteRe = Note.RE.getTone(0.5, SAMPLE_RATE);
byte[] noteMi = Note.MI.getTone(1.5, SAMPLE_RATE);
line.write(noteDo, 0, noteDo.length);
line.write(noteRe, 0, noteRe.length);
line.write(noteMi, 0, noteMi.length);
line.drain();
line.close();
}
public enum Note {
DO(0.0f), DO_DIEZ(1.0f),
RE(2.0f), RE_DIEZ(3.0f),
MI(4.0f),
FA(5.0f), FA_DIEZ(6.0f),
SOL(7.0f),SOL_DIEZ(8.0f),
LYA(9.0f),LYA_DIEZ(10.0f),
SI(11.0f);
private final double mPhase;
Note(double phase) {
mPhase = phase;
}
public double getNoteFrequencies() {
double index = getmPhase()/ 12.0d;
return 440 * Math.pow(2, index);
}
public static Note getNote(double phase) throws Exception {
Note findNote = null;
for (Note note : Note.values()){
if (note.getmPhase() == phase){
findNote = note;
}
}
if (findNote == null)
throw new Exception("Note not found: Ilegal phase " + phase);
else
return findNote;
}
public byte[] getTone(double duration, int rate){
double frequencies = getNoteFrequencies();
int maxLength = (int)(duration * rate);
byte generatedTone[] = new byte[2 * maxLength];
double[] sample = new double[maxLength];
int idx = 0;
for (int x = 0; x < maxLength; x++){
sample[x] = sine(x, frequencies / rate);
}
for (final double dVal : sample) {
final short val = (short) ((dVal * 100f));
// in 16 bit wav PCM, first byte is the low order byte
generatedTone[idx++] = (byte) (val & 0x00ff);
generatedTone[idx++] = (byte) ((val & 0xff00) >>> 8);
}
return generatedTone;
}
private double sine(int x, double frequencies){
return Math.sin( 2*Math.PI * x * frequencies);
}
public double getmPhase() {
return mPhase;
}
}
1
votes
if you are looking for just a class to call for a beep, then try this: (some code borrowed from Thumbz)
package ditdah;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.SourceDataLine;
public class Beep {
protected static final int SAMPLE_RATE = 16 * 1024;
public void play(double freq, int length) {
final AudioFormat af = new AudioFormat(SAMPLE_RATE, 8, 1, true, true);
try {
SourceDataLine line = AudioSystem.getSourceDataLine(af);
line.open(af, SAMPLE_RATE);
line.start();
byte[] toneBuffer = this.createSinWaveBuffer(freq, length);
say.it(toneBuffer.toString() + " " + toneBuffer.length);
int count = line.write(toneBuffer, 0, toneBuffer.length);
line.drain();
line.close();
} catch (LineUnavailableException e) {
say.it(e.getLocalizedMessage());
}
}
public byte[] createSinWaveBuffer(double freq, int ms) {
int samples = (int) ((ms * SAMPLE_RATE) / 1000);
byte[] output = new byte[samples];
//
double period = (double) SAMPLE_RATE / freq;
for (int i = 0; i < output.length; i++) {
double angle = 2.0 * Math.PI * i / period;
output[i] = (byte) (Math.sin(angle) * 127f);
}
return output;
}
}
0
votes
I'd just like to point out that there is a very efficient algorithm for generating sine waves.
DSP Trick: Sinusoidal Tone Generator http://www.dspguru.com/dsp/tricks/sine_tone_generator
