unless your back is straight
  you are not listening
  you are not listening
  unless your eyes are closed

Try as many or as few of these at the same time as you wish or are
able to:

*) Close your eyes.

*) Listen to everything, not just what you think you're supposed to.

*) Put your fingers in your ears.  Play with your ears, and see how
   this changes the sound.

*) Be sure you're not too hungry, too full, too thirsty, or otherwise
   uncomfortable for easily resolved biological reasons.

*) Relax.  Take a deep breath.

*) Straighten out your back.

*) Try to pay attention to something other than what you're hearing.

*) Answer this question: "What does the sound remind me of?"

*) Promise yourself that you will never discuss what you think of the
   sound with anyone else.  Resolve to free yourself from having to
   come up with opinions you think your peers will find acceptable (or
   conversely, opinions you think might anger your enemies).