Audvis - Audio Visualization
Why is this so fast?
All the expensive math is done once per frame or subframe. Calling "driver(from,to)" is cheap, because all analyzing was done before and here you are only reading from one prepared result and making much simpler math.
How to escape Party Mode?
Press ESC, or press Alt+F4, or just switch windows by Alt+Tab
How to fix random Blender crash while rendering scene with AudVis Shape Modifier?
Short answer: use Render -> Lock Interface.
More info: https://developer.blender.org/T60094