Lecture 3: Audition Flashcards
What are the 4 major features of sound?
- waveform
- phase
- amplitude
- frequency
Perception of sound corresponds to what 2 things?
loudness and pitch
Pressure amplitude is responsible for what?
loudness
Frequency is responsible for what?
pitch
What is compression/condensation?
when neighboring air molecules are pushed together
What are pure tones?
sounds produced by objects vibrating in simple harmonic motion
What does wave form project?
how projection of sound moves in time and space
What is sound wave propagation?
sound wave moves through the air as each particle sets its neighbor in motion
What is the sinusoidal function?
simple harmonic motion that generates a sine wave
Low frequency is related to what type of vibration?
slow
High frequency is related to what type of vibration?
rapid
What is a phase shift?
relationship between 2 sine waves with the same frequency that are displaced in time
What is the range of human hearing?
20-20000 Hz
What is the range for uncomfortable loudness?
100 dB
At what range would humans feel pain?
120-140 dB
At what range do humans have the best hearing?
6000-8000 Hz
What shape of the extrernal ear contributes to what?
- protection
- sound gathering providing a high frequency boost >3000 Hz
- sound localization and elevation detection
- alters effective spectrum of sound
What shape of the extrernal ear contributes to what?
- protection
- sound gathering providing a high frequency boost >3000 Hz
- sound localization and elevation detection
- alters effective spectrum of sound
Where does the middle ear start?
tympanic membrane/eardrum
What is the middle ear space?
malleus, incus, stapes which attach to the oval window
What is the smallest bone in the body?
stapes
What is impedance matching?
when sound goes from air to water, they reflect and undergo a 30 dB loss in intensity
What is the most helpful impedance matching?
area advantage
What are the 3 types of impedance matching?
- area advantage: 27 dB
- ossicular lever action: 1.3 dB
- curved membrane buckling mechanism: 6 dB
What is the inner ear a site for?
transduction of sound pressure waves to action potential
What is the vestibular portion of the inner ear?
cochlea
Where does actual hearing begin?
What are the 3 parts of the cochlea?
- scala vestibuli (perilymph)
- scala media (endolymph)
- scala tympani (perilymph)
What are the characteristics of the scala vestibuli?
- located at the top
- similar to extracellular fluid
What are the characteristics of the scala media?
- located in the middle
- has its own fluid
What are the characteristics of the scala tympani?
shares fluid with vestibuli
What is tonotopic organization?
organized with purpose to recognize different frequencies
In a “stiffness gradient”, high frequencies cause vibrations where?
near the base
In a “stiffness gradient”, low frequencies cause vibrations where?
near the apex
What is the organ of corti comprised of?
sensory hair cells and other supporting cells
How many rows are there of inner and outer hair cells?
- 3 rows of outer
- 1 row of inner