Fundamental Frequency , Voicing and Pitch

Question 1

Explain the source filter theory of production

Answer 1

It is based on the idea that there are two main stages in speech production

1. the generation of the basic sound source
2. Filtering of a basic sound source

most of the filtering of a source spectrum is carried out by the part of the vocal tract anterior to the sound source
In the ase of the glottal sound source, the entire supra-glottal vocal tract is the filter.

Question 2

What do periodic or aperiodic sound sources mean?

Answer 2

A periodic sound source= voicing,
An aperiodic sound source = whispering or voiceless fricative /h/
They may also be mixed, e.g breathy voice.
These are all examples of glottal sound sources

Supra- glottal sound sources are used contrastively in speech and are aperiodic (e.g random noise)

Question 3

Explain the characteristics of the voiced glottal source

Answer 3

has its own spectrum which includes spectral fine structures (harmonics and some noise) and a characteristic spectral shape sloping downwards at approximately -12 db/octave

Fundamental frequency is a characteristic of voiced glottal source acoustics (perceived as vocal pitch)

Question 4

What are the 4 Types of sound sources?

Answer 4

Voicing= phonation associated with all the vowels and diphthongs of English

Noise= Associated with whispering, voiceless fricatives and the aspire /h/

Transients= Pulse like energy associated with the initial bursts of plosives [t] and [p]

Silence= periods of silence associated with the stop pharse of plositves [p] and [t]

Question 5

What does quasi periodic voice source mean?

Answer 5

It means that if you look at the time domain of human speech ,you’ll find that voiced sounds (e.g voiced plosives /b/ /d/ /g/ or nasals /n/ /m/ or liquids etc..) each of the identifiable repeating patterns are called a cycle. The duration of each cycle is called period length or glottal pulse duration.It is known as ‘quasi periodic’ because each cycle has a slight variation.

Question 6

What is the aerodynamic myoelastic theory of phonation?

Answer 6

it is the idea that muscular forces of the larynx and pressure forces of air exiting the lungs act to set the vocal folds into motion by a series of rapid opening and closing.

Question 7

What is fundamental frequency?

Answer 7

It is a property of the source and is perceived by the ear as pitch. It is the frequency of vocal fold vibration and correlates with changes in vocal fold tension an sub glottal air pressure. The F0 of the adult human male averages 100 hz whilst females = 200 hz. The F0 is a measure of how high or low the frequency of a persons voice sounds.

Question 8

How is F0 measured?

Answer 8

It is measured by 1000/tms (glottal pulse duration)

Question 9

What are harmonics?

Answer 9

the vocal signal is a complex periodic wave made up of several simple periodic waves. Each simple wave is called a harmonic. The F0 is the first harmonic or H1. there is a harmonic at each interval of the F0 up to infinity.

Harmonics decrease in amplitude as frequency increases.

Question 10

How does F0 differ with age?

Answer 10

• There are differences that exist before and after puberty
• Different in older women F0
• differences between men and women as they grow older

Question 11

What studies support the F0 differences in age?

Answer 11

Lee et al 1999- Acoustics of children’s speech : Developmental changes of temporal and spectral parameters.

Whiteside Hodgson and Tapster (2002) Vocal Characteristics in pre-adolescent and adolescent children : a longitudinal study

Question 12

How does F0 differ with Sex ?

Answer 12

• Females have a higher F0 than males (males= bigger larynges and thicker vocal folds)
• Puberty changes in males and females are different (males= dramatic, females = slow steady and decrease over time)

Question 13

What studies support the sex differences in F0?

Answer 13

• Whiteside 2001 - sex specific fundamental and formant frequency patterns in a cross sectional study
• Lee et al 1999 - Acoustics of childrens speech : developmental changes of temporal and spectral parameters
• Whiteside, Hodgson and Tapster (2002) Vocal characteristics in pre=adolescent and adolescent children : a longitudinal study

Question 14

What study supports similarities in F0 as a result of family resemblance ?

Answer 14

Whiteside and Rixon : Speech tempo and fundamental frequency patterns : a case study of male monozygotic twins and an age and sex matched sibling.

Question 15

How do Accent differences affect F0?

Answer 15

Different languages use different registers - F0’s are different

• Even within the UK accent can affect F0.

Question 16

What did Mennen et al (2011) find regarding accent differences?

Answer 16

speakers of different anguages or dialects may use characteristically different F0 ranges and provide validation of the anecdotal belief that female speakers of english and german differ in F0 range

Question 17

what did Fry (1955) find regarding accent differences?

Answer 17

• found that the perceptual cues to accent are pitch legnth and loudness (pitch is a perceptual correlate of F0!)
• F0 differences in itself is sufficient for listeners to percieve accent and that the magnitude of the f0 change is insufficient.

Question 18

How can F0 be manipulated in Language?

Answer 18

1. slowing the rate of our vocal folds (creating creaky voice/vocal fry are low F0’s whilst falsetto = high F0
2. Potraying different linguistic messages e.g Stress (increases F0), intonation and prosody (questions=rising F0, statements=falling F0)
3. In mandarin they use F0 to imply completely different messages by using the same phonemes just changing the F0

Question 19

How do emotions impact on F0?

Answer 19

emotions impact on F0 as if somebody is sad then they will have a low F0 but if they are happy, their F0 will appear much higher.

Question 20

What sex differences does Lee et al’s (1999) study show regarding F0?

Answer 20

• F0 differences between male and female become significant beginning from 12 years
• females have a pitch drop from age 7 however only small and no change after age 12. (V different to the 78% drop in males)
• appears to be an over-shoot of acoustic parameters before reaching adult levels in both males and females
• a bigger within subject variability for female speakers- maybe due to the inherent differences in vocal fold physiology of high voice.

Question 21

What age differences does Lee et al’s (1999) study show regarding F0?

Answer 21

• for male speakers there is a 78% drop in F0 between the age of 12 and 15.
• There is no significant pitch change after 15 years.
• From age 5-8 there is a 50% decrease in variability with no change in F0 average (suggesting stabilisation of pitch control)

Question 22

What do Whiteside Hodgson and Tapster (2002) believe is important to be wary of regarding voice development in adolescence?

Answer 22

There is a considerable amount of variability. e.g hollein et al 1994 - although males demonstrate onset of adolescent voice change between the ages of 12.5 to 14.5 on average - some began the process as early as 10.5 years and in others its onset did not begin until 16.5 years.

Also , important to take in to consideration voice classification (tenor, baritone or bass) and voice type on the F0 data of age groups.

Question 23

What did Whiteside, Hodgson and Tapster (2002) find regarding F0?

Answer 23

F0 data showed decreases between T1 and T2 for both males and females of all age groups.

• Boys of all ages displayed decreases in F0 but none had values within +1 SD of the young adult mean value of 96.4 Hz at T2
• Girls were either within +1 SD of the young adult mean of 202.2 Hz or below it by time 2. (suggesting that some girls may achieve F0 values within adult female range by the age of 9.5 and that the change in female larynges from pre-adolescence through adolescence may be minimal in some females.

Question 24

What did Whiteside , Hodgson and Tapster (2002) theorise about why females as young as 9.5 years had similar F0 to young adult females?

Answer 24

May be that the young adults are adopting a particular speech style, contributing to their higher laryngeal setting and higher fundamental frequency values.

Question 25

What did Whiteside and Rixon (2013) find regarding family similarities and fundamental frequency?

Answer 25

They found that in a study of two MZ twins and an age and sex matched sibling,there was evidence for greater between twin similarities in mean F0 compared to their age and sex matched control.

However, though mean F0 had more twin similarities (indicating greater genetic influence here) other parameters such as more global variation petterns in F0 and more loca F0 changes within voiced stretches of speech utterances are shaped more by environmental factors such as accent dialect reading style speaking style and multilingualism.

Question 26

What did Mwangi et al (2009) find on the effects of aging on F0?

Answer 26

as the body ages the anatomy of the larynx changes, and therefore the vocal cords do not vibrate at the same frequency throughout. gneeral trend = considerable decrease between the ages of 26-43 followed by a marginal decline between 43-70.

Question 27

What did Mennen (2012) find regarding cross language differences in F0?

Answer 27

speakers of differene languages use characteristically different F0 ranges and provides validation for the anecdotal belief that female speakers of English and German differ in F0 range.

The linguistic measures used in his study highlighted the different points in the intonation contour , alongside some differences in the typical frequency of distribution of tones. (F0 range influence by the phonological and or pohnetic conventions of the language being spoken not solely an artifact of physiological factors or cultural differences.