Speech Science-important stuff lec 2-5

quiz 1

Frequency

Hz

Pressure

Dynes

Pitch

Mels

Power

Watts

Intensity

dB SPL

Loudness

Phon

Intensity Level

Watts/m²

Sound Pressure Level

SPL

Human hearing threshold

20-20KHz (20,000)

Comprehension range

100-5,000Hz

Vocal Cord Vibration

80-500Hz

Speed of sound in air velocity

c= 344 m/s

Speed of sound in sea velocity

c= 340 m/s

Period vs Wavelength

period is cycle/time

wavelength is distance

speed of sound is NOT dependent on

frequency/wavelength

Inertia and elasticy have a

inverse relationship for (inertia and elasticity)

What is pitch affected by?

by intensity

(higher intensity=higher pitch)

What is the perceptual correlate of frequency?

Pitch

What is the perceptual correlate of intensity?

Loudness/Amplitude

What is affected by frequency?

Loudness is affected by frequency

Speed of sound is determined by 2 things

1) density of a medium: solid, liquid, gas

2) phase of a medium: tighter bonds of solid transmit sound energy faster (tuning fork on table vib faster)

Wavelength is inversely related to?

frequency

higher Fo=shorter wavelength; (reflect off)

lower Fo=longer wavelength; (travel through barriers)

2 things about pitch

1) ear is not equally sensitive to all frequency changes

(120-220Hz is good; 1000-1100Hz is bad)

2) can perceive lower frequencies(pitch) more easily than higher ones

Frequency and Pitch are related in a ?

non-linear way

higher pitch= higher frequency

wavelength depends on?

speed of sound and frequency

λ= c/f

what is the special property of harmonics?

harmonics decrease in amplitude as the frequency increases

3 boundary behaviors

1) reflection: bounce off

2) diffraction: bending around

3) transmission: going through

3 types of interference

1) constructive interference: 1 + 2= 3 (higher amplitude)

2) destructive interference: 1 + 1= 0 (cancellation/silence)

3) complex interference: mixed parts w both

3 types of phase

1) in phase: compression meets compression, higher amplitude

2) 90 degrees out of phase: slightly off, ear wont notice diff/little effect on speech

3) 180 degrees out of phase: compression meets rarefaction= silence

what is interference?

2 or more waves meet

what are complex tones?

when 2 or more pure tones of different frequencies are added

2 types of complex wave

1) complex periodic wave: vibration patter repeats (ex: voice, piano, bells)

2) complex aperiodic wave: no Fo, no harmonics, no pattern (ex: most natural sounds)

3 types of noise

1) continuous: ocean, rustle of leaves, wind, white noise

2) transient: clap, headphones, drum beat

3) combination: street noise

2 types of vibration

1) free: the obj/medium vib freely after initial disturbance

2) forced: 1 medium sets another into vibration; driven by an outside source that’s an oscillator

what is natural/resonant frequency?

object vibrates most easily and with the widest amplitude

resonant freq= speed/wavelength

propertied of a medium

1) stiffness: more stiff=higher frequency

2) mass: more mass=less frequency (inverse)

3) length: more length= less frequency (inverse)

2 types of resonators

1) mechanic: objects

2) acoustic: air in a completely or partially enclosed container

volume of container influences resonant frequency

more volume=less frequency

less volume=more frequency

2 types of tuning

1) sharply tuned: light damping; small range of Fo (vibs at a long time)

2) broadly tuned: heavy damping; large range of Fo (vib dies quickly)

what are formants?

natural frequencies that get intensified

physical

Frequency

Amplitude/Intensity

Duration

Perceptual

Pitch

Loudness

Length

Algebraic relationship between periodicity/frequency

to find freq: F=1/T (cycles)

to find period: T=1/P (time)

sound has no

mass or weight

sound travels in a

longitudinal wave

newtons 1st law of motion/inertia

“an object in motion stays in motion an object at rest stays at rest”

will accelerate/decrease only if acted upon by an outside force

what 2 things are needed for an object to vibrate?

inertia and elasticy

newtons 3rd law of motion/ equivalent exchange

“for every action (force) there is an equal or opposite reaction”

what is density?

amount of material packed in a given volume

(less volume=more density; more higher=less density)

d= mass/volume

solid liquid gas

solid= holds shape and volume

liquid= maintains volume and takes shape of container

gas= no shape or volume

what is pressure?

force exerted by collision of molecules with each other and wall of container

less pressure=more volume

more pressure=less volume

period

time to complete 1 cycle

cycle

1 vibration (compression + rarefaction)

frequency

number of cycles completed in 1 sec

damping

decrease in amplitude of displacement over time

compression

increased pressure

rarefaction

decreased pressure

soundwave is a

compression and rarefaction

the ___ the frequency, the ____ the period

the higher the frequency the lower the period

the lower the frequency the higher the period

Simple harmonic motion is represented as

a sine wave

sound needs 3 things

1) source of energy

2) vibrating source

3) medium of transmission