Lesson 11 Flashcards
what is sound?
physical = sound is pressure changes in the air or other medium
perceptual = sound is the experience we have when we hear
condensation
vibrations push the surrounding air molecules together. Causes a slight increase in the density of molecules near the diaphragm
rarefaction
speaker diaphragm moves back in, air molecules spread out to fill in the increased space
sound wave
pattern of air pressure changes
pure tone
occurs when changes in air pressure occur
in a pattern described by a mathematical function called a sine wave
frequency (Hertz- Hz)
number of cycles per second that the pressure changes repeat
amplitude
the size of the pressure change
tone chroma
notes separated by octaves sound the same
tone height
increase in pitch that happens when the frequency is increased
what does timber depend on?
- tone’s steady-state harmonic structure
-time course of the attack and decay of the tone’s harmonics.
what does loudness depend on?
amplitude AND frequency
what is the outer ear composed of?
-pinnae
-auditory canal (3cm)
-tympanic membrane/eardrum
resonance
occurs in the auditory canal when sound waves that are reflected back from the closed end of the auditory canal interact with sound waves that are entering the canal
middle ear (small cavity - volume = 2 cubic cm ), composed of what?
ossicles (3 smallest bones):
1. malleus/hammer
2. incus/anvil
3. stapes/stirrup
oval window
middle ear muscles
inner ear
cochlea (cochlea partition)
organ of Corti (contains hairs, the receptors for hearing)
basilar membrane
tectorial membrane
1 row of inner hair cells
3 rows of outer hair cells
phase locking
firing at the same place in the sound stimulus- associated with pitch
temporal coding
major mechanism of pitch perception
what is the path the brain sound takes?
auditory nerve fibers from the cochlea synapse subcortical structures:
1.cochlear nucleus
2.superior olivary nucleus
3. inferior colliculus
4.medial geniculate nucleus
5. primary auditory cortex (A1)
(SONIC MG)
which brain area is associated with pitch?
anterior auditory cortex
