Pitch is related to the frequency of sound wave. The higher the frequency, the higher the pitch of the sound seems to be. The frequency ranges for different living things vary, for example, human can hear frequency range from about 20-20,000 Hz, while dogs can hear as low as 15Hz. That is why some people says in order to test genuine Sony headphones (genunine ones can produce frequencies lower than human can hear), put in on the dog's ear and if the dog screams then the headphone is genuine product, nto a counterfeit.