Audiology Week 2

What is a waveform?

a graphic representation of the shape of a wave that indicates its characteristics (like frequency or amplitude)

What is periodic motion?

motion that is repetitive and repeats itself on regular time intervals

What is the cycle of a waveform?

a cycle of a waveform is when the motion completes one full repetition

What is frequency?

number of cycles per second

F= number of cycles/time (seconds)

unit is Hertz (Hz)

What is a period?

how long it takes to complete 1 cycle

Period (T)= time (seconds)/ number of cycles

unit is just time, so typically seconds or milliseconds

What is the perceptual correlate of frequency?

pitch

What happens to pitch if frequency increases?

the pitch of the sound will increase

What type of relationship does frequency and period have?

an inverse relationship

when one goes up the other goes down

f= 1/T or T= 1/f

What is wavelength?

the distance in space between two adjacent identical points on a wave

What is the relationship between frequency and wavelength?

frequency is inversely related to wavelength

high frequency, short wavelength

low frequency, long wavelength

What is the relationship between period and wavelength?

period and wavelength are directly related

as period is longer, wavelength gets longer

What is amplitude?

the maximum magnitude

What is the perceptual correlate of amplitude? What is the relationship between them?

volume

if amplitude increases, volume increases

What is the phase relationship?

describes the difference between phases of two periodic waveforms as they cycle through time

What is in-phase?

when two waveforms have the same frequency and same starting phase

What is out-of-phase?

when two waveforms have the same frequency but different starting phases

What happens when something is 180 degrees out-of-phase?

sound is cancelled out

how noise cancellation headphones work

What are mechanical waves?

mechanical energy is transferred from one molecule to another

What is a medium?

in order for waves to be able to move they need something to move through (called a medium) this is the matter that occupies a space

a medium can be solid, liquid, or gas (basically anything that is made up of molecules)

What are the two common types of mechanical waves?

transverse waves

longitudinal waves

What are transverse waves?

the particles in the medium move perpendicular to the direction the wave is traveling

What are longitudinal waves?

the particles in the medium move parallel to the direction the wave is traveling

Are sound waves longitudinal or transverse?

longitudinal

What is condensation?

spots where particles are bunched together creating increased density

What is rarefaction?

spots where particles are spread apart creating decreased density

What do the particles look like when there is a high peak?

particles are close

What do the particles look like when there is a low peak?

particles are far apart

What is sound diffraction?

sound can bend around stuff

low frequencies can bend around stuff due to their long wavelengths

What is the Doppler Effect?

what causes the pitch of a siren to change as an ambulance approaches you and then passes

a shift in the frequency of a sound wave resulting from the movement of a sound source

What is reflection?

if sound doesn’t get absorbed then it gets reflected

sound waves bounce off hard slick surfaces like tile, concrete, hardwood

What is reverberation?

when sound bounces around in a space

What is absorption?

sound doesn’t just travel on forever; the energy gets absorbed by either:

• friction between the air molecules

• by materials in the environment

opposite of reflection

What is constructive interference?

occurs when you add two in-phase waves are added together and the magnitude increases

What is destructive interference?

occurs when you add two out-of-phase waves together and the magnitude decreases

What are beats?

slow periodic amplitude fluctuations caused when two waves that are very close in frequency interfere with one another

How do you calculate how many fluctuations you hear in one second?

f_beats= f₂ - f₁