[BU3] Module 2: Sound Theory, Longitudinal and Transverse Waves, Frequency

sound

the sensation stimulated in the organs of hearing by mechanical radiant energy transmitted as longitudinal pressure waves through the air or other medium

physics

in _______, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid

human physiology and psychology

in _______, sound is the reception of such waves and their perception by the brain

sound level

intensity of sound (energy, loudness, strength, amplitude)

frequency

repetition of a periodic event (pitch, tone, wavelength)

propagation

originationn of transmission of sound energy (path, elapsed time)

sound generation

produced when pressure oscillations are generated in an elastic mediium at rates that are detectable by a hearing medium

sound generation

a form of energy produced by vibrating objects

sound generation

a waveform that travels in matter

sound generation

occurs whenever there is a disturbance of an elastic medium, when pressure is generated as rates detectable by a hearing medium, or when physical phenomenon stimulates hearing

sound transmission

occurs through an elastic medium by means of wave motion

sound wave

a pattern of disturbance caused by the movement of energy traveling through a medium as it propagates away from the source of the sound

sound waves

created by object vibrations and produce pressure waves

sound wave

longitudinal pressure wave in air or an elastic medium occuring once sound isi generated and then trannsmitted

wave length

the distance from any one point to the next point of a corresponding phase within a sound wave

wave length

can be measured as the distance from crest to crest or from trough to trough

amplitude

the maximum deviation of a wave from its average value; maximum amount of displacement of a particle on the medium from its rest position

crest

the point on the medium that exhibits the maximum amount of positive; upward displacement from the rest position

trough

the point on the medium that exhibits the maximum amount of negative or downward displacement from the rest position

decibel

originally used to relate the intensity of sound to an intensity level corresponding to human sensation; a unit for expressing the relative pressure or intensity of sounds on a uniform scale

sound power

describes the strength at the source, and sound intensity or sound pressure; describes the strength of the receiver, accounting for disitance room, surface sound absorption, room geometry and other environmental effects

sound phenomenon

similar to acoustic phenomenon, referred to as dispersion of a sound wave separating into its component frequencies as it passes through a material or a medium

reflection

in which the resultant sound energy returned from a surface that is not absorbed or otherwise dissipated upon contact with surface

echoes

reflection of sound waves also lead to _________

parallel

________ reflective surfaces can cause echoes and flutter

true

[t/f] echoes are different than reverberations; echoes occur when a reflected sound wave reaches the ear more than 0.1 seconds after the original sound wave was heard

rough

______ walls give a room a feel of full and lively sound

smooth

______ walls fail to give the room a feel of full sound

refraction

the change in the direction of waves as they pass from one medium to another

refraction

bending of the path of waves

true

[t/f] waves passing from one medium to another will undergo refraction

diffusion

refers to the reflection of sound off a convex or uneven surface; the process of spreading or dispersing radiated energy so that it is less direct or coherent

concave

___ surfaces focus sound

convex and splayed

_____ and ____ surfaces diffuse sound

diffraction

refers to the bending of the travel of sound caused by an obstacle in its path; being of waves around small obstacles and the spreading out of waves beyond small opening

diffraction

involves a change in direction of waves as they pass thru an opening or around a barrier in their path

true

[t/f] the amount of diffraction increases with increasing wavelength and decreases with decreasing wavelength

wave

a disturbance that propagates energy from one place to another without transporting any matter

longitudinal wave

in this type of wave, the medium or the channel moves in the same direction with respect to the wave/parallel to the direction of the wave propagation

longitudinal wave

in this type of wave, the movement of the coils is from left to right and forces other particles to vibrate

rarefaction zones

zone in longitudinal wave where medium expands

compression zones

zone in longitudinal wave where medium compresses

longitudinal

sound waves are _____ waves

longitudinal

sound waves in the air

longitudinal

primary waves of an earthquake

longitudinal

ultrasound

longitudinal

the vibration of a spring

longitudinal

fluctuations in a gas

longitudinal

tsunami waves

transverse wave

the medium or the channel moves perpendicular to the direction of the wave

transverse wave

here, the coils move up and down as the waves move horizontally

transverse

ripples on the surface of the waters

transverse

secondary waves of earthquakes

transverse

electromagnetic waves

transverse

waves on a string

transverse

ocean waves

longitudinal

it acts in one dimension

transverse

it acts in two dimensions

longitudinal

the wave cannot be polarized or aligned

transverse

the wave can be polarized or aligned

longitudinal

the wave can be produced in any medium such as gas, liquid or solid

transverse

the wave can only be produced in solid and liquid's surface

longitudinal

made of rarefactions and compressions

transverse

made of trough and crests

frequency

refers to how often the particles of the medium vibrate when a wave passes through the medium

pitch

the number of times per second that a sound pressure wave repeats itself

high-low

sound waves with high frequence produce ____-pitched noise, and low frequency produce ____-pitched noise

880 hz

hertz considered high pitch

55 hz

hertz considered low pitch

20 hz

hertz considered infrasound

20000 hz above

hertz considered ultrasound

hertz

number of waves that pass through a particular place in a second

infrasound

humans cannot hear _________ because it is too low pitched

20hz-20000hz

sounds with frequence of _____ are generally audible to humans

ultrasound

humans cannot hear __________ because it is too high pitched

dogs

this species can detect sounds with frequencies until 50000 hz

high

if the wavelength is more compressed, the frequence and pitch are ____

low

if the wavelength is more loose, the frequency and pitch are _____

pitch

determined by the frequence of vibration of the sound waves that produce them

pitch

the quality of sound that distinguishes an acute or strident note from a grave or flat note