You could use the ease expression to limit the min and max of the zoom. Ease takes an input(in this case both channels) that has numbers from say 0 to 12 and converts them to other numbers say from 0 to 100 proportionally.
Alt click your logo layer’s scale and try this expression:Min = [50,50];
Max = [100,100];
myMusic = thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider");
ease(myMusic,0,30,Min,Max)
The Min would be 50% scale, the Max 100%(You can change these variables)
In my example the numbers 0 and 30 represent the low and high volume of the audio I was using. Select your both channels and using the graph bottom you can quickly see what the low and high volume points are and should change those numbers accordingly.
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.