From the X24 users manual...
6-1 FOXMOTION
FOXMOTION is a unique feature that allows you to “move” the sound between the internal speaker and an external speaker at varying rates to portray an effect of the sound (animal) moving. There are 5 different rates or speeds at which you can have FOXMOTION operate. The lower the setting, the more gradual the transition from one speaker to the other will be. To activate FOXMOTION, turn on the X24 and X24 remote. Begin sound playback like normal. Access the X24 remote main menu24and select the FOX FEATURES item. Select FOXMOTION and change it to“ on.” Then select the Rate item directly beneath it to adjust the speed that FOXMOTION operates at.