Using audio to adjust the Y positioning of an object

Here's the workflow:

1. Select the Both Channels Audio Amplitude value in the Timeline and open the Graph Editor
2. Make sure the Graph Editor is set to Value and look for the maximum and minimum values and make a note of them
3. Make a note of the minimum and maximum Y value you want for the Pogo Stick character
4. Start an expression for the Pogo Stick character's position value
5. Add the following expression to Position:

t = thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider");
y = ease(t, MinBothChannelValue, MaxBothChanelValue, -MaxUpMove, 0);
[value[0], value[1] + y]

If your minimum Both Channels value was 2.4 and the maximum was 8.5, and you wanted to Pogo Stick to move up 400 pixels, then the second line would look like this:

y = ease(t, 2.4, 8.5, -400, 0);

Because a pogo stick makes the loudest noise when it hits the ground, accelerates with some smaller noises, and then is quiet, you won't get a perfect motion. A better option would be to have a single bass drum or timpani sound for every jump. You will get a smoother arc.

If you want a perfect emulation of a pogo stick bouncing, animating three keyframes (bottom, top, bottom) and adjusting the Speed Graph to give you a nice smooth arc, then adding a simple loopOut() expression might get you a much better look with a lot less fiddling. 

Compare that to what I get from a pogo stick recording: