@Override
    public void startEvent(){
        try{
            sourceVelocity = Double.parseDouble(df_1.format(Double.parseDouble(inputVelocitySource.getText())/2));
            observerVelocity = Double.parseDouble(df_1.format(Double.parseDouble(inputVelocityObserver.getText())/2));
            frequency = (int)((1/(Double.parseDouble(inputFrequency_doppler.getText())))*100);
            refreshRate = (frequency*sourceVelocity);
            if(sourceVelocity<1 && sourceVelocity>=0.5){
                fade = fadeRate*25;
            }else if(sourceVelocity<0.5){
                fade = fadeRate*80;
            }else{
                fade = sourceVelocity/(400-((1.5-sourceVelocity)*410));
            }
            produceSoundWave(0);
            dopplerAnimationTimeline.play();
        }catch(Exception ex){
            JOptionPane.showMessageDialog(null, error);
        }        
    }