Haasenfeffer was inspired by the Haas effect (http://en.wikipedia.org/wiki/Haas_effect). You can use Haasenfeffer to add subtle adjustments to the perceived "space" of stereo or mono sound sources. Delay times can be panned, or set independently for each channel. The filter frequency is adjusted around a center value, and each filter can be linked or panned as well. The X-Y pad approximates a sonic space by adjusting the balance of delay times and filter levels.
While playing around with this effect, I decided it would be beneficial to have two modes for how the filters interact in the X-Y display. One mode has the L/R frequencies linked, the other mode has them "pan" so that they go in sort of opposite directions. I may add LFOs to the X-Y pad in future versions, but these can be easily automated by some other great Max for Live devices available at http://www.maxforlive.com/.