The audio visualizer code available here for download is for the Java ONE 2009 presentation A Music Visualizer with the Java Media Framework API and JavaFX Technology, TS-4842.

This download is also from my book JavaFX Special Effects: Taking Java™ RIA to the Extreme with Animation, Multimedia, and Game Elements.

The book offers a more complete description of how the classes work than the PDF available from the presentation page.

Here is the download:
Audio Visualizer source code.