The Nature of Hearing

Question 1

What is sound?

Answer 1

A vibratory energy transmitted by [pressure waves] in the air or other media. For example, a hammer applying pressure to a nail causes vibration through the air, the hammer, nail, and the wood.

Question 2

Requirements for sound to exist:

Answer 2

1. There needs to be a source of vibratory energy
2. That energy will then be delivered to and cause a disturbance to any medium (as long as it has mass, is compressible or elastic)
3. The disturbance from the medium will carry in the form of sound waves moving away from the source, conforming a compression (condensation) followed by an expansion (rarefaction)
4. Condensation and rarefaction will result in pressure changes propagated through the medium.

Question 3

Simple Harmonic Motion (Sinusoidal Motion)

Answer 3

Back-and-forth movement

Question 4

Sinusoidal Waveform

Answer 4

The graphic representation of a simple harmonic motion. As the displacement of the air molecule vibrates through the pressure wave, the SHM also describes the pressure changes of sound over time.

Question 5

Intensity (Properties of Sound)

Answer 5

The magnitude of a sound. (Perception of loudness)

Question 6

Two ways Intensity can be described

Answer 6

• Units of power (the amount of energy transmitted per second over a specified area of 1 square meter)
• Acoustic power/intensity level is expressed in watts/meter^2
• Expressing level of sound

Question 7

Formula to measure sound power:

Answer 7

dB IL = 10 log (power/reference power)

Question 8

Formula to measure sound pressire:

Answer 8

dB SPL = 10 log (power/reference power)^2 or

dB SPL = 20 log (pressure/reference pressure)

Question 9

Frequency

Answer 9

The speed of vibration and is related to the perception of pitch. The number of cycles occurring in 1 s, expressed in hertz (Hz).

Question 10

Outer Ear

Question 11

Middle Ear

Question 12

Inner Ear

Question 13

Auditory Nervous System

Question 14

Absolute Sensitivity of Hearing

Question 15

Differential Sensitivity

Question 16

Properties of Pitch and Loudness

Question 17

Role of physical properties of sound and what they play in the generation of sound

Question 18

Identify the properties of sound and their psyhcologic equivalents

Question 19

Define the quantities of the physical properties of sound and explain how they are used to describe hearing ability

Question 20

Identify the three major components of the ear and their specific anatomic structures

Question 21

Explain the roles of the anatomic structures of the ear in perceiving sound

Question 22

Identify the nuclei of the NCS

Question 23

Hydraulic Energy

Question 24

Sensory Cells

Question 25

Cortex