Could you try that code snippet?
MediaPlayer mPlayer = new MediaPlayer();
AssetFileDescriptor descriptor = getAssets().openFd(soundName);
long start = descriptor.getStartOffset();
long end = descriptor.getLength();
mPlayer.setDataSource(descriptor.getFileDescriptor(), start, end);
mPlayer.prepare();
mPlayer.start();
while (mPlayer.isPlaying()) { }
mPlayer.prepare();
mPlayer.start();