What is the purpose of the outer ear?

The outer ear includes: auricle (cartilage covered by skin placed on opposite sides of the head) auditory canal (also called the ear canal) eardrum outer layer (also called the tympanic membrane)

The ear canal – the auditory canal. Once the sound waves have passed the pinna, they move two to three centimetres into the auditory canal before hitting the eardrum, also known as the tympanic membrane. The function of the ear canal is to transmit sound from the pinna to the eardrum. Hope this helped :)

pitch- the definition of pitch is as follows:

"the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone."