Exam 2 PHYS 147

auricle (pinna)

collects sound and helps determine where sound comes from

auditory canal

carries sound waves toward the eardrum

tympanic membrane (eardrum)

vibrates in response to sound

malleus

received vibrations from eardrum

incus

transfers vibrations between malleus and stapess

stapes

transfers vibrations to oval window

eustachian tube

balances air pressure in middle ear

cochlea

converts mechanical vibrations into neural signals

basilar membrane

separates sound by frequency

hair cells

convert vibrations into neural activity

auditory nerve

sends sound information to the brain

oval window

recieves vibrations from stapes

round window

allows pressure relief for cochlear fluid

helicotrema

tip of cochlea; associated with low frequencies

masking

when one sound makes another sound harder to hear

critical band

a frequency range where sounds stimulate overlapping regions of the basilar membrane

combination tones

extra tones created by nonlinearities in the ear when two tones are played simultaneously, especially at higher levels

organ of corti

contains hair cells that convert mechanical vibrations into electrical signals

outer hair cells

they amplify the motion of the Basilar membrane, especially for low amplitude vibrations

lungs

push air upward to produce airflow

trachea

carries air from lungs toward the larynx

larynx

houses the vocal folds

vocal folds

vibrate to produce voiced sound

glottis

opening between the vocal folds

pharynx

passage above the larynx; part of the vocal tract

tongue

changes vocal tract shape to form different speech sounds

hard palate

firm roof of the mouth

soft palate

can raise to close off the nasal passage

lips

shape or obstruct airflow at the mouth

nasal cavity

resonates when sound/air is directed through it

lowpass filter

attenuates the higher frequencies above its cutoff

highpass filter

attenuates the lower frequencies below its cutoff

bandpass filter

attenuates frequencies below and above the passband

feedback

information the child recieves about their own speech after producing it

reference

a target or model the child compares their speech against

burst energy

a brief release of energy, often associated with stop consonants such as /p/, /t/, or /k/

voice energy

periodic energy from vocal fold vibration (in a spectrogram it may appear as a regular horizontal harmonic bands)

noise energy

aperiodic energy, often appearing as irregular or diffuse energy (fricatives such as /s/ and /ʃ/ involve noise energy

formants

resonant frequency regions of the vocal tract, commonly shown as prominent bands in a speech spectogram

prosodics

features of speech beyond individual consonants and vowels, such as pitch/fundamental frequency, loudness, duration and rhythm, stress and intonation

additive noise

extra unwanted sound is added to the speech signal (speech becomes harder to distinguish)

bandwidth limitations

some frequencies are removed or reduced because the communication systems only transmits a limited frequency range (parts of the speech sound are lost)

peak clipping

the highest and lower amplitude peaks of the waveform are cut off (the waveform is distorted and the shape of the signal changes

signal-to-noise ratio

how strong the desired signal is compares with the unwanted noise (positive SNR: signal level is higher than noise level; SNR=0: signal and noise levels are equal; negative SNR: noise level is higher than signal level)

sampling frequency

the number of times per second a signal is measured

Nyquist frequency

the highest frequency that can theoretically be recorded without aliasing is the half of the sampling frequnecy

bit resolution

tells you how many bits are used to represent the amplitude (loudness level) of each sample