Android Visualizer FFT / waveform affected by device volume?

I was also facing the same problem, but it is working when i am enabled the Eqaulizer and Visualizer for same seession id.I dont know the reason for it ,i checked it remove the equalizer from visualizer class in api demos it is working as you said.

 Equalizer mEqualizer = new Equalizer(0, SessionId);
 mEqualizer.setEnabled(true); // need to enable equalizer
 Visualizer mVisualizer = new Visualizer(SessionId);