Following up on his unique method for Ethereal Morphing Letters (Radio Waves of Autotraced text masks), Satya Meka has a new tutorial at AEtuts. In Create a Sound Reacting 3D Waveform Animation without 3rd Party Plugins, he uses audio data to control wave frequency of a Wave World height map and adds Ball Action with a Brighten Twist. Brute force alternatives for isolating audio frequencies may or may not be more time consuming, but you also get background on how Expression Controls can be implemented and how he created the preset.
See Satya's blog Gutsblow for additional thoughts on his tutorials (and Presets). Here's samples of sound reacting ball waves and ethereal morphing:
more ethereal morphing from gutsbl'w on Vimeo.