Properties of Sound and Speech Acousrics - AUD EXAM 1

Acoustics

the phyical properties of sound, how they travel and interact with objects

psychoacoustics

(mind) how we perceive sound

how is a sound produced?

when an object is set into motion (plucking a guitar string)

pure tones

simple and repetitive (sound)

simple vibration

pure tones(isolated sound), what they use in hearing test

complex vibration

multiple pure tones, everyday noise

Fast Fourier Transformation (FFT)

process of translating sound from complex to simple, vise versa

sound propagation

the movement of sound energy through a medium (like air, water, or solids)

rarefraction

air particles are farther apart (low density + pressure)

condensation

air particles are closer together (high density + pressure)

longitudinal wave

vibrate back and fourth (parallel, side to side)

Transverse Wave

vibrate at right angles (perpendicular, up/down)

speed of sound in air

343ms (1126ft/s)

inertia

tenacity of an object to resist change (object in motion want to stay in motion)

elasticity

structures ability to return to og place after being displaced/deformed

frequency

number of cycles per second (Hz)

frequency formula

F = 1/T

period

time it takes to complete 1 cycles

human audible range

20 Hz - 20,000 Hz

period formula

T = 1/F

Wavelength

distance it takes to complete 1 cycle

reflection

bounces off

diffraction

how a wave bends around an opening

refraction

how a sound bends as it changes medium (under water)

absorption

when a sound wave is absorbed

ex of absorption

cinderblock wall = reflect, tile ceiling = absorb

doppler effect

a slight increase or decrease in frequency as the sound source moves toward or away from you

why does doppler effect occur?

wavelength in front gets shorter and the wavelength behind the moving source get longer

starting phase

where vibration begins and is express in degrees

instantaneous phase

where the wave is within that 360-degree circle at a given millisecond