Sun's Audio file format is a binary format with the exception that the first 4 
bytes -- a identification of ".snd" or otherwise in hex as 0x2e736e64.

Successful ways to reduce the size of .au audio files:

1) Removing the entire header and description sections of a AU audio file will 
   still allow the file to play and makes the file smaller.

2) Empty air may be removed from a file by removing large chunks of 'ÿ's.