Playing with computeSpectrum() and PV3D 2.0 alpha (Great White). The mesh reacts to sound by having its vertices moved along the Z axis (X and Y coordinates are fixed). Had a problem with FlatShadeMaterial failing to render on regions of coplanar faces; small creases were made in the mesh to fix it.
Sound analysis was made with SoundMixer.computeSpectrum(), FFTMode set to true (a frequency spectrum results in a more interesting visualization) and stretchFactor set to 4. Increasing the stretchFactor value means analyzing a smaller frequency range of the sound —thus ignoring non-audible high frequencies. The 16×16 vertex grid represents the average values of left and right channels.
Music Is Music As Devices Are Kisses Is Everything (5:20) by 65daysofstatic (from the 2007 album The Destruction Of Small Ideas) is the song; a nice fit for this visualization because of the contrasting quiet and loud parts —the visualization of the piano notes in the quiet sections is very clear.
View SWF (5MB, move mouse on X direction to change rotation, music plays 10 times)
Update: comments closed because of spam.
Update #2: this experiment was featured on PV3D blog — 9 Cool Experiments in 3D.