The acoustic signal along with normal engine vacuum or fuel signal causes fuel to be delivered to the engine. We have all heard the sound of a fat, over-jetted engine such as you hear at high altitude or very warm weather riding. It's the whaaa whaaa sound. This is a slow, fuel rich reversionary pulse wave in the intake tract. The reverse of this is also true.
Detonation is an extreme lean condition that generates a sharp reversionary pulse wave.
Remember that we are moving a very light weight emulsified fuel charge. This is the reason it is so responsive to the engine's fuel needs over such a broad range. Throttle response is extremely fast and smooth. Throttle lag is virtually eliminated. Throttle lag is where the airflow in your carburetor out accelerates your fuel, which finally catches up.