166b084d.46410f77.ffdf4bad.36c20550.cdata is an audio file from the computer game Command & Conquer 3 by Electronic Arts. It contains audio data compressed with either an EA variant of ADPCM aparently known as XAS or an EA variant of Mpeg Layer 3 audio. (we dont know how to tell which files are compressed with which codec yet) There may or may not be a header attached.