Handout 5: Vocal Acoustics Flashcards
opening and closing of the VFs during phonation results in a generation of a complex periodic sounds w a certain ____ ______
fundamental frequency
fundamental frequency is
lowest freq of a periodic waveform
what does Hz represent
cycles per second
the frequency of a waveform can be determined by
- the period is inversely related to freq
- need to measure the duration of a single cycle of vibration (peak to peak measurement)
then you need to divide 1000 ms by the durtion of the period, lets say its 10 ms
1000 ms / 10 ms = 100 Hz aka 100 cycles per second
frequency
of cycles per second (Hz)
pitch
quality of sound governed by the rate of vibrations - inc freq, inc pitch
Praat is an example of a…
automaic pitch detection program
have been developed to automatically and continuously measure pitch periods over long periods of speech
no program or algorithm is 100% accurate; abnormal voices can be very difficult to measure pitch
average fundamental frequency is
F0 average over the duration of a speech task or sample of connected speech
average fundamental frequency by age and gender…
infants - 350-400 Hz
children - 270-300 Hz
young F - 220 Hz
young M - 120 Hz
Older F - 180 Hz
Older M - 140 Hz
frequency variability
emotion, stress, or accent on syllables, grammatical forms all contribute to prosody and F0 variability
what does too much or little F0 variability indicate
may sound abnormal and indicate a voice prob
F0 range is
the diff bw the highest and lowest F0 in a sample of connected speech
frequency variability gender and age diffs
infants - 1200 Hz
Children - 150-200 Hz
YM - 65 Hz
YF - 95 Hz
OM - 78 Hz
OF - 100 Hz
certain voice disorders can have a sig reduced F0 range called
monopitch
during prolonged ____ the F0 range should be v low .. higher values indicate a prob with ____ _____
vowels
pitch control
maximum phonational frequency (MPFR)
obtained while producing stepping or gliding tones
range from the lowest to the highest tone that a person can sustain
max phonational frequency range males vs females
males = 600 Hz range
females = 850 Hz range
trained singers will have a ____ MPFR and those with voiced disorders may have a ____ MPFR
Wider
narrower
speech amplitude is largely determined by …
the amplitude of sound that is created by phonation - speech and voice amp is roughly equivalent
average amplitude level
- very dependent on speech activity/context
- measured by taking the average value over the duration of a speech sample
average amplitude level of a normal average conversation is
68-70 dB at 12 inches
age gender effects for average amplitude?
lower for children, women slightly less than men, older = younger
amplitude variability
amplitude variations due to emotions, stress, or accent on syllables, grammatical forms
what is the standard deviation of amplitude on neutral sentences
about 10 dB SDofA
what is monoloudness
when people w voice disorders show reduced range/SDofA
dynamic range
softest phonation to max loudness of phonation - about 50 dB to 115 dB
when is there concern about dynamic range
if its less than 30 dB in the midrange of F0
what is a voice range profile or phonetogram
dynamic amplitude plotted across F0 range
what are cycle to cycle variations
an estimate of the average variation in each adjacent cycle of vocal fold vibration
jitter
average cycle to cycle vibration in the time (period/freq) of vibration
normal jitter is
less than 1% or less than 0.1 ms
Shimmer
average cycle to cycle variations in the amplitude of vibration
normal shimmer value
0.5 dB
harmonics to noise ratio
the ratio bw periodic and non periodic components of speech sounds - i.e. desired signal to the level of background noise
the amplitude of the voice signal at the specific frequency of F0 and all of the related harmonics are determined and this harmonic amplitude is divided by the amplitude of other non F0 harmonic frequencies (vocal noise)
what are the non F0 harmonic frequencies considered to be in the HNR
vocal noise
what will a normal voice have for HNR
relatively small amplitude of vocal noise frequencies relative to the high amplitude of the F0 harmonic signal frequency
about 15-20 dB
a ____ HNR is associated w a poor voice, ____ with a normal voice
lower, higher
voice problem will have a HNR below ____
15 dB
cepstral peak prominence (CPP)
- another measure of intensity/amplitude/prominence of vocal harmonics relative to the vocal noice
- involves second freq analysis - freq is called quefrency
– createds a new plot called a cepstrum - original harmonics appear as prominent peak relative to surrounding vocal noise
CPP values obtained from prolonged “ah” that are ____ are abnormal
below 15 dB
4 ways to measure voice quality
jitter
shimmer
HNR
CPP
