Speech Science Quiz 1 Flashcards
What is wave?
disturabance being composed of vibrations that move within a medium
The speed of the wave is….. not dependingn on ……
constant
amplitude and frequency
Do particles travel with the wave?
No! They don’t! They oscillate back and forth. It’s the disturbance that travels with the wave.
When molecules constantly move around in random patterns @high speeds refers to ……
Brownian motion
Wave that the particles move in a parallel to the direction of the wave
longitudinal wave
Wave that the particles move perpendicularly to the direction of the wave
transverse wave
Pulse wave refers to
single disturbance
Examples of pulse wave
1 stone thrown into a pond
row of dominoes falling
a single clap
Voiced & voiceless plosives; African clicks
Frequency is
cycles per second (Hz)
Cycle is
1 alternating compression and rarefraction
Frequency range of sound vibrations that humans can hear
20Hz - 20,000 Hz
Sounds too low in frequency to be audible are called ……
subsonic
Sounds too high to be audible
ultrasonic
Speech frequency
100-5,000 Hz
Fundamental frequency of the human voice created by the vocal cords is in the ….….. Hz range
80-500 Hz
Audible harmonics of the fundamental frequency and sounds made in the oral cavity are extended to ……
5,000 Hz
Period is
time to complete one cycle
Relationship of Frequency and period
Frequency = 1/t Period = 1/frequency
If frequency = 100 Hz, the t =
1/100 = 0.01
If t= 0.005, the frequency =
5/1000 = 200 Hz
Period and frequency of a wave are inversely related
Explain the relationship
Higher f shorter period
Lower f longer period
Wavelength
distance traveled during 1 cycle
Wavelength depends on
frequency and speecd of sound
Relationshop between frequency and wavelength
Explain
inverse relationship
Higher frequency shorter wavelength
Lower frequency longer wave length
Amplitude is
the size of the local disturbance (compression and rarefaction of air molecule)
Magnitude of the oscillation
Intensity is
the power per unit area
proportional to the square of the amplitude
Unit of amplitude
dB
Intentisy scale
dB SPL
Decibels are
a manageable measurement of wide range of human hearing
1 decibel = …… of a bel
1/10th
An increase of 10 dB represents
sound level: ten-fold increase (10x)
perceived loudness: twice
Base indicates
how much each unit increases
Exponent indicates
how often the base is multiplied by itself
Does 0 dB mean there is no sound?
No! It means the sound present is the same as the reference sound
0dB
the reference sound for the threshold for normal human hearing
below which the sound waves are too small to be perceived
30 dB is ….. time as intense (compared to 0 dB)
1000x
30 dB is perceived as …… time louder (compared to 0 dB)
8 times
Intensity diminishes with increasing …….
distance
Each doubling of distance from the source to the listener reduces the SPL by …..dB
6 dB
Frequency is perceived as …..
pitch
Amplitude /Intensity is perceived as
loudness
Duration perceived as …..
length
Duration is
time domain measured in seconds (words, phrases & sentences)
in milliseconds (individual vowels & consonants)
We have greater sensitivity to the dofferences between ….. compared to …….
Lower pitches
Higher pitches
Localization of high f (~1500Hz) is dependent on …….
head shadow effect
The head casts shadow that in turn attenuates sound by at least …. dB or up to ….. dB
6dB/ 20dB
Why higher frequencies tend to get blocked by the head
because the wavelength is short
The ear located the nearest to the source of the sound is called
the leading ear
The ear located opposite to the source of the sound is called
the lagging ear
Waveform is ….
a graphical display that represents the alternating compressions and rarefractions of air molecules that make up the longitudinal sound pressure wave
Compression is
When molecules are tighly packed
Rarefaction is
when molecules are spread apart
Instrument that displays any sound as a waveform
oscilloscope
Sine (sinusoid) waves are simple ways that represent ….
a pure tone (single frequency)
Complex waves represented ……
the sum of simpler waveforms
Complex waves contain …… frequency (s)
more than 1 frequency
many soundwaves of different frequencies
Complex waves can be ….. or …..
periodic or aperiodic
Periodic complex waves are produced by
How is the pattern?
irregular vibration
repetitive pattern (simple (pure tone) or complex)
Examples pf periodic complex waves
sine waves, waves created by most musical instruments
Aperiodic waves have cycles of …..
They are random vibration and repeatable pattern
different length
Examples of aperiodic waves
noise (most natural sounds) ocean, Leaves rustling dishes clattering clap snare drum (lack of perceived single frequency)
When an aperiodic signal produces a noise of short duration, it is considered…..
(transient/ continuous signals)
transient
Examples of transient signals
dropping a book
clicking your tongue
one clap of your hands
Examples of continuous signals
hiss, wind blowing , paper rustling
Sub-type signals of aperiodic waves
Transient & continuous signals
In normal speech, …… acts as a source of periodic sound
the larynx
Voice is treated as ……….. wave
complex periodic wave
quasiperodic
In whispered speech, the larynx acts as a source of ……. sound
aperiodic
……… can provide sources of aperiodic sound
Articulators
Speech sounds that are catogorized as periodic
Vowels/ diphthongs
Nasals
Liquids
Glides
(All create resonance within yhe vocal tract > repeatable signal)
Aperiodic speech sounds
Fricqtives, africates, stops/plosives
Produced by constriction of an airway with the articulators creating a noisy sound
Speech sounds categorized as both or mixed periodic and aperiodic and why?
Voiced fritcatives, affricates and stops
because voicing has a periodic feature
Speech sounds categorized as continuous sounds
vowels/ diphthongs Nasals Liquids Glides Fricatives
Speech sounds categorized as transient sounds
stops/ plosives
Affricates
Interference occurs when
waves are combined
- frequency generated from 2 sources
- reflected from a barrier and competing with itself
Types of interference
constructive & destructive interference
What is constructive interference?
when the net effect of the interaction of 2 or more wave > a new wave with a larger amplitude
What is destructive interference?
when the net effect of the interaction of 2 or more wave > a new wave with a lower amplitude
Boundaries are
the inteface between 2 mediums
The nature of the boundary ….. the sound.
influences
Possible boundary behaviors:
reflection (bouncing backwards off a boundary)
diffraction (bending around an obstacle without going through a boundary)
transmission (going through a boundary)
Reflection of sound waves off of surfaces can lead to 1 of 2 phenomena
an echo or a reverberation
Reverberation is determined by
the size of a room (physical vol.) and amount of acoustic reflection
Early reverberation …… speech perception since …..
Critical distance
enhances/ they arrive soon enough to be integrated with the direct sound
~ 8 ft.
Late reverberation arrives ….. to
too late to be integrated with the direct signal or the early reverberation components (more than 0.1 of a second)
The ……. the reverberation time (RT), the more …… speech is
longer/ unintelligible
If the level of reverberationis still high enough, they …..
interfere with the direct sound by creating masking
Echos occur when
a reflected sound wave reaches the ear more then 0.1 seconds after the original sound wave was heard
1st sound will have died out
2nd sound arrival perceived as the second sound rather than the prolonging like reverberation
Fundamental frequency is
the basic frequency of a vibrating body
the lowest frequency contained in a complex periodic waveform
Abbreviation of fundamental frequency
F-zero or F-nought
A sound’s fundamental frequency is the main info telling your ear …..
how low or how high a frequency is (pitch)
Harmonics
complex waveforms +more than 1 frequency of vibration
Fundamental frequency is …… harmonic
first
A resonator is
sth set into a forced vibration by another vibration
2kinds of resonators
- Mechanical resonators
2. Acoustic resonators
Key characteristics of a resonator
- it does not initiate the vibration energy
- vibration created elsewhere
- vibration forces the resonator to vibrate in sympathy
Resonance is
The tendency of a body to vibrate more readily @certain frequencies
Natural frequency is influenced by mechanical characteristics of the object, including
stiffness
mass
length
included air vol
Objects that act as filters …..
add or subtract from the complex input waveform
Acoustical resonator
Enclosed container that the air is inside is set into vibration
Examples of acoustic resonators in our body
the vocal tract & ear canals
Any tube with one closed end and one open end, are called
quater-wave resonators
Difference between waveform and line (power) spectrum
Waveform: time (x-axis) and amplitude (y-axis)
Line (power) spectrum: Amplitude & frequency > snapshot
The spectogram is
graphic representation of sound in terms of their component frequencies
Horizontal axis (x) of spectogram
time
Vertical axis (y) of spectogram
frequency
Darkness in spectogram shows
Intensity of each frequency
2types of band spectogram
wide band
narrow band
Wide band
combines harmonics
vocal fold pulses show as vertical lines
Narrow band
individual harmonics
formant displayed horizontally
no vocal pulses shown
