[MBAtarga]

Can't help you along the lines of your playback sound idea, however, I do have a suggestion as an alternative.

Years back my wife and kids (young at the time) took a day trip to Chattanooga TN. There was a museum with a scientific exhibit on bats that we just happened to drive by and looked interesting so we decided to stop.

One of the neatest parts of the exhibit was a platform you stepped on/into and placed your head at the correct level to match the openings in some scaled up bat ear mock-ups (made of fiberglass or maybe paper mache'.) IIRC, they were almost 2 fight high. They allowed a human to experience how well bat's can "hear" - because of their exaggerated size. You could rotate the platform to point the ears across the room and pick up conversations from far away.