We know the speed depends on the kinetic energy. Imagine that we have 3 iron balls equally spaced and kept in space (zero gravity condition).
If i push the first ball slowly it would travel slowly and hit the middle ball and it would travel much more slower to hit the final ball. But if i had pushed the first ball with higher energy the collision would have been much faster.
But why isn't this happening with air? We know air molecules are spaced and if i push air with higher velocity, why wouldn't the speed of sound increase?