How can a f-curve be used in an animation in BGE? I created some f-curves for different frequencies from an MP3 files, using the "bake sound from f-curve" function from the Key menu in the f-curves editor. The curves are assigned to a keyframe and scale the cubes while the music plays the MP3 has been added as a sound strip in VSE (looks like spectrum analyzer).

How could the f-curves be used in the BGE, could they possibly assigned to an action?
F-curve is generally used for controlling actions, I assume that you were asking "how to use action in BGE".

The simplest way is to set the Actuator type to Action. Then choose the action you want, and tweak a few settings within it, as shown below. Hope I didn't misunderstand that.





EDIT: I'm feeling that I sort of misunderstood that, did I? :-\