To control noise at the source, it is first necessary to determine the cause of the noise and
secondly to decide on what can be done to reduce it. Modification of the energy source to
reduce the noise generated often provides the best means of noise control. For example, where
impacts are involved, as in punch presses, any reduction of the peak impact force (even at the
expense of a longer time period over which the force acts) will dramatically reduce the noise
generated.