747-400x startup sound problem

I recently started my pmdg and noticed that i realy did not hear the engines spool up so i went into the sound file and played the I recently started my pmdg and noticed that i realy did not hear the engines spool up so i went into the sound file and played the startup engines WAV file and heard nothing. Is this a problem or just me.Here is a video of what im talking about http://www.youtube.com/watch?v=49KI_IKaVHA