Flashcards in Voice Production Deck (29)
What is the vocal apparatus?
The set of organs that we use when we speak:
the lungs - generates air flow
the supra laryngeal vocal tract - the pharynx, the south and the nasal cavity
What is the source filter theory?
Believes we have 2 functional components which are responsible for speech
Source filter theory - stage 1
The source - a periodic wave is generated in the larynx (the source) by vibration of the vocal folds. The rate of vibration determines the fundamental frequency of the signals, affected the perceived pitch of the voice
What does the rate of vibration in the larynx determine?
The fundamental frequency of signals, and the pitch
if high rate - high pitch
if low rate - low pitch
Source filter theory - stage 2
The wave is filtered in the supra laryngeal cavities of the vocal tract (the filter), creating broad bands of energy called vocal tract resonances or formants - energy is distributed homogeneously - when we speak, changing shape of supra laryngeal
What is the source?
What is the filter?
The vocal tract
The larynx has a set of cartilage which all do different things
Phonation (production): vibration of the vocal folds
When we speak, we use our vocal cords inside the larynx
air expelled out of the lungs provides energy to the oscillators = the vocal cords
this cyclic opening/closing of the glottis generates a sound wave called the glottal wave
How many times does the opening and closing of the glottis occur when we speak?
130 times for males
240 times for females
What is the most common organ used in communication?
What are typical vocal sounds composed of?
Several sinusoidal waves which appear on spectrograms as evenly spaced, parallel, narrow, frequency componants
What is the fundamental frequency?
The lowest of the parallel frequency components
The fundamental frequency determines the pitch
the variation of it with time determines the fundamental frequency contour
What are harmonics?
Multiples of the fundamental frequency
What is the pitch of a voice?
The perceived height of a voice
determined by the fundamental frequency
What controls the vocal folds vibration rate?
The length, mass, tension and stiffness of the vocal folds affect the fundamental frequency: the longer and heavier the folds, the lower the pitch (I you want to speak low pitch, relax folds so mass is heavier, if you tense, speak with high)
Gender/age variation - children have shorter folds than women, than men
Age and gender affects on fundamental frequency
strong sexual dimorphism: males have longer vocal folds
in pre puberty, there are no differences in vocal fold length and pitch, however, there is a dramatic enlargement of the larynx which occurs in males at puberty. Castrated males have female voices, females with testosterone develop males voice
How much bigger is the male larynx?
pitch is 80% lower
male - 24mm
female - 17mm
This is the vocal tract
What happens to the larynx in the first few years?
It descends - newborns can suckle and breathe at the same time, but adults will choke if they do this
What is the bad thing about having a descended larynx?
We could choke - evolutionary cost
What cavity is created when the larynx descends?
The pharynx - a two tube vocal tract, with the tongue in the middle
What are vocal tract resonances?
Formants (concentration of energy) - they shape the spectral structure of the speech signal, they are central to human speech as they provide the acoustic variation at the basis of vowels and consonants
What do longer vocal tracts produce?
Is the distribution of energy homogeneous?
Not across frequencies, some frequencies have more energy than others
What do peaks and valleys represent?
The resonances that take place in the cavities of the vocal tract
How does the vocal tract length affect voice gender in adults?
Males are 10% taller than females, the descent of the larynx results in a 1.2 sexual dimorphism in vocal tract length
the adult male vocal tract (16.5cm) is longer than the female vocal tract (14cm). as a consequence, formants are on average 20% lower in adult males than females
How does the vocal tract length affect voice gender in kids?
In children, body size is identical and vocal apparatus is not sexually differentiated before puberty, however we can discriminate between girls and boys