Sine Wave Sound Generator in Java

Question

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.

Answer 1

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;
    }
}