To be able to reply to the above mentioned question, one should seek understanding the boundaries of the human sense of hearing. Many people understand that the human ear cannot pick up sounds a large number of animals are able to detect. For instance, people don’t pick up the sound produced by a dog whistle, though a dog pricks up the ears of its anytime a man blows into such a whistle. Those good waves have a frequency which goes beyond the boundaries of what the human ear can hear. A sensitive car audio equalizer can recognize a lot of the audio waves which remain undetected by the human ear.
