Pitch Perception

Exam 3

pitch

perceptual correlate of frequency

pure tone

1 frequency

complex tone

combination of multiple frequencies

harmonic complex tones

repeated over time, resolved/unresolved

resolved harmonics

low numbered, separate rep. in cochlea, heard

unresolved harmonics

high numbered, no individual peaks of excitation, not heard

how are complex tones represented in the cochlea

time waveforms at output of filters

low numbered (resolved) harmonics

resemble pure tones
diff. firing pattern of AN

high numbered (unresolved) harmonics

not resembling pure tone
produce complex wave form

how does pitch change with frequency

magnitude estimation method

mel scale

unit of pitcch

mels associated with a 1000 hz tone

1000 mels

pitch increases in the mel scale when frequency ___, but not linear

increases

T/F pitch can be affected by intensity

true

how is pitch affected with high frequencies

pitch increase with intensity increase

how is pitch affected with mid frequencies

pitch does not change with intensity

how is pitch affected with low frequencies

pitch decreases with intensity increase

frequency discrimination

smallest frequency difference of sound that is detected

weber’s fraction for frequency discrimination

Δf/f

is weber’s fraction for frequency discrimination constant?

no, varies with frequency

webers fraction with frequencies below 1500 Hz

decreases with frequency

webers fraction with frequencies above 1500 Hz

increases with frequency

place code theory

pitch determined by place of max excitation of BM

temporal code theory

relies on phase locking

freq. represented by time between spikes

problem with temporal code theory

phase locking only until 5k Hz

what theory is place coding for complex tones based on

helmholtzs place theory

place coding for complex tones

pitch of complex tone determined by place of max excitation in cochlea

pitch is extracted from

low order, resolved harmonics

do resolved harmonics need to be present in place coding for complex tones

always need to be present

temporal coding for complex tones

pitch perceived by measuring periodicity of info from resolved/unresolved harmonics

temporal coding for complex tones - resolved harmonics

nerve fibers phase lock to temporal fine structures

temporal coding for complex tones - unresolved harmonics

nerve fibers phase lock to the envelope

do resolved harmonics need to be present for temporal coding for complex tones

do not need to be present for pitch perception

missing fundamental

even if f0 not there, you can hear pitch

place code theory problem

pitch heard when only unresolved harmonics present - cannot explain pitch of missing fundamental

pitch of harmonic complex determined by

first 5-8 harmonics

pitch perception uses

temporal and place coding