Acoustics

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Cards (39)

How is sound converted into an electrical signal?
Through a series of remarkable steps in the ear
What generates sound when someone speaks?
Vocal chords in the larynx vibrate
What is the main task of the auditory system?
Receive and decode sound information
What do sound waves represent?
Periodic air pressure variations
What is the role of the ear?
Convert sound waves into electrical impulses
How does the ear transmit information to the CNS?
Via the auditory nerve
What are the two types of waves mentioned?
Mechanical wave and electromagnetic wave
What characterizes mechanical waves?
Local oscillation of material without moving far
What is a sound wave?
A travelling periodic pressure vibration
What is sound defined as?
The vibration of matter perceived by hearing
What are the generic properties of sound waves?
Frequency, wavelength, period, amplitude, intensity, speed
What is frequency a measure of?
The number of occurrences of a repeating event
What is the formula relating frequency and period?
$f =$ $\frac{1}{T}$
How is pitch determined?
Primarily by frequency
What is the audible frequency range for humans?
16Hz to 20000Hz
What are infrasound and ultrasound?
Vibrations below 16Hz and above 20000Hz
How does hearing ability change with age?
Upper frequency limit generally decreases
What is wavelength in relation to sound?
The distance between repeating units of a wave
What is the formula for wavelength?
$\lambda =$ $vT$
What does amplitude measure?
The magnitude of change in oscillating variable
What is wave speed?
How fast a wave travels through a medium
What is the speed of sound in dry air at 21 °C?
344 m/s
How does the speed of sound vary?
Depends on the medium and temperature
What is sound intensity defined as?
Sound power per unit area
What is the threshold of hearing intensity?
The minimum sound level detectable by normal hearing
What is the decibel scale used for?
To quantify sound levels relative to a reference
What are the three parts of the ear?
Outer ear, middle ear, inner ear
What does the outer ear include?
Pinna, ear canal, tympanic membrane
What is the function of the middle ear?
Contains ossicles and Eustachian tube
What is the role of the inner ear?
Includes the cochlea and hearing nerves
How does sound travel through the ear?
From outer ear to inner ear via vibrations
What causes hearing loss?
Interference with sound transmission in the ear
What is conductive hearing loss?
Interference in sound transmission to inner ear
What is sensorineural hearing loss?
Damage to the auditory nerve pathway
How is hearing loss measured?
In decibels hearing level (dBHL)
What is considered normal hearing range?
0 to 20dB
What are the thresholds for different types of hearing loss?
Mild: 25-39dBHL, Moderate: 40-69dBHL, Severe: 70-94dBHL
What is pure tone audiometry (PTA)?
A key hearing test for identifying thresholds
What are the steps of sound transmission through the ear?
Outer ear collects sound waves
Sound waves travel down the ear canal
Ear drum vibrates
Middle ear bones amplify vibrations
Vibrations transmitted to inner ear (cochlea)
Fluid movement in cochlea activates hair cells
Electrical signal sent via auditory nerve to the brain