Hearing science

Mass (kg)

Amount of matter that is present

Propagation

the process by which a sound wave, carrying energy, travels through a material medium like a gas, liquid, or solid

Sound Generation

applying energy to cause rapid back-and-forth motion in an object, such as plucking a guitar string or striking a drum

Source Filter Theory for vowel prod

• peaks are formants

• Source and filtering

–P(f) = U(f) T(f) R(f)

–U(f) and R(f) is considered to be constant

fundamental physical quantities of a wave

mass, time, length

Derived (secondary) physical quantities

Displacement, velocity, acceleration, force, pressure

Vowel sound source

vocal folds and glottis

Phonation

Rapid variation of the narrow glottis aperture to produce a pulsing sound source

Phonation mechanism

A series of high-speed

cinematography for one cycle

of glottal action on phonation

Glottal area/airflow

The waveform of the glottal sound source

Spectrum

Two characteristics of the glottal ____

–F0 and the harmonics

–The amplitude pattern of the components over frequency: -12 dB/octave

Length (meter)

Distance between two points

Time (t)

Standard unit: second

Displacement (meter)

Change in spatial position

Vector

Direction sensitive (how much + which way) (ex: Force 50N downward)

Scalar

Direction independent (size, amount, value) (ex:temp and speed)

Velocity (v)

The displacement in a unit of time (m/s)

Acceleration (a)

Change in velocity in time (a= v2 - v1/ t)

Force (N)

Push or pull that generates acceleration (F=m x a)

Pressure (p)

The force applied on an area (p= F/Area(m2))

Amplitude/ Magnitude (dB

Maximum displacement (bigger means louder)

Frequency (Hz)

How fast? (Cycles per second) (pitch

To find Frequency

1/T

Pitch

Highness or lowness of sound

Elasticity

Ability for object to return to its original state after being deformed

Angular velocity

object's angular position changes over time (how fast it rotates or revolves

Inertia

Resistance to changes in motion

Sine wave

simplest sound in nature
- d = Amp sin(2 pi f t)

Acoustic parameters of sine wave

amplitude, frequency, phase

Ratio

Ix/Ir (Ix= the target sound intensity, Ir= 10^-12 w/m² reference sound intensity

logarithm

math tool that helps to compress giants numbers to smaller (finding the exponent) 2_?=8 = log₂ (8)

dB IL

10 Bel = 10 log₁₀ (Ix/Ir)

Bel: to compress a big number into a much smaller number

log₁₀ (Ix/Ir)

millisecond and second

1 sec = 0.001 ms

Sound acoustic energy

1 second/ meter²

Sound Intensity (w/m² )

amount of sound energy transmitted in one second over and area of m2

Intensity range of Sound

10^-12 w/m² ~ 1 w/m2

dB SPL

deciBel Sound Pressure Level

dB IL

deciBel Intesity Level

I(intensity sound level), p(sound pressure), Z(acoustic impedance)

I=p(2nd power)/Z

Sound Power (watt)

The amount of sound energy that is transmitted in one second

Phase = 0

Starts at 0 moves +

Phase = pie/2

Starts at max displacement on the + side

Phase = 3pie/2

Starts on the max displacement on - side

Phase = pie

Starts at 0 moving -

Scientific motion

change in an object's position over time relative to a frame of reference.

Simple harmonic motion

repetitive, back-and-forth movement where the restoring force (the force that pulls the object back to its center) is always directly proportional to the object's displacement from its equilibrium (or middle) position and always acts in the opposite direction of the

Uniform circular motion

object moving along a circular path at a constant speed

Complex sound

the sound that is composed of two or more than two sine waves

• any sound that is not sinusoidal

Source-filter theory of
speech production

• Glottal sound source

• Filter by the vocal tract

• Radiation characteristics of the mouth-opening

Phonation Mechanism

A series of high-speed

cinematography for one cycle

of glottal action on phonation

The waveform of the glottal sound source

contains:

• area

• airflow

Spectrum

Two characteristics of the glottal ___

• F0 and the harmonics

• The amplitude pattern of the components over frequency: -12 dB/octave

Shaping of the Vocal Tract

Model of the pharyngeal-oral tract

• Vowel shaping by the configuration of the pharyngeal-oral tract.

• Tube model: resonate the vocal sound

Spectrum of the neutral vowel /ə/

• Resonant frequencies

500, 1500, 2500 Hz …

Spectrum Format

• Resonance of the vocal tract

• - Formant: F1, F2, F3, and F4 …

• Location of formant frequency

1. Length of the vocal tract

2. Location of the constriction

3. Degree of the narrowness of the constriction

F1 Rule

Pharyngeal Constriction = Longer = lower __

(vertical)

ex: females have higher __ cause their pharyngeal constriction is shorter

F2 Rule

Oral Cavity smaller = Higher ___ freq

(horizontal)

Lip Rounding rule

Used for back vowel

Radiation Characteristic

• The additional filtering effect when the speech sound is radiated beyond the month into the atmosphere.

High-pass filter: +6 dB/Oct

(U)s

• glottal sound

(T)s

(P)s

Vertical lines: harmonics

• has 3 Resonant peaks

(R)s

Vowel Formants

Includes: (constrictions) Front, Back, and Central Vowels: shorter = higher F2, longer pharyngeal = lower F2

• Talker difference

Adults – children, male – female

• Phonetic context difference

• different adjacent consonants or vowels

Acoustic Analysis of Speech

• Spectral information

Spectrum

Spectrogram

• F0

F0 and f0 contour

• Amplitude

Speech intensity and intensity contour

• Duration

Misperception

taking past information of formants to fill in blanks of sound they think/ or didnt hear 

ex: hearing loss, foreign language