Introduction to Hearing Sciences Exam 1 Review

Sound

A form of energy, a condition of disturbance of particles in a medium

How many kilometers are in a meter?

0.001

How many centimeters are in a meter?

100

How many milligrams are in a gram?

1000

How many micrograms are in a gram?

1000000

X⁰ = ?

1

X¹ = ?

X

X⁻ʸ = ?

1/(Xʸ)

Aᵇ x Aᶜ = ?

A⁽ᵇ⁺ᶜ⁾

Aᵇ / Aᶜ = ?

A⁽ᵇ⁻ᶜ⁾

(Aᵇ)ᶜ = ?

A⁽ᵇ*ᶜ⁾

What does Y equal? X=logₐy

Y=aˣ

logₐa = ?

1

logₐ1 = ?

0

logₐaˣ = ?

x

log₁₀10 = ?

1

log(a*b) = ?

loga + logb

log(a/b)

loga - logb

logaᵇ = ?

b(loga)

Scalar Quantity

Only contains magnitude

Vector Quantity

Contains magnitude and direction

Area(Ar) Equation

L*L (m²)

Velocity(c) Equation

d/t (m/s)

Acceleration(a) Equation

c/t (m/s²)

Force(F) Equation

m*a (N)

Pressure Equation

F/a (Pa)

Sound is created by _____ of objects in our everyday world

vibrations

Vibrations create _____ _____ which propagate through a medium

pressure waves

Pressure waves are received and perceived by the auditory system as _____

sound

All sounds have _____ and _____

mass, elasticity

Mass

The amount of matter in an object as characterized by weight and density

Elasticity

The ability of an object to return to its original state after a force has been exerted

Vibration

The movement that results when a force is exerted on an object

Resistance causes a vibration to _____

stop

Speed of Sound Equation

√Elasticity/Density

Wavelength(λ) Equation

c/f

Does a higher frequency create a longer or shorter wavelength?

Shorter

Frequency(f) Equation

1/t

Period(t) Equation

1/f

Sine wave equation

d(t) = Asin(2πft + Θ)

Displacement

The amount of movement away from a state of equilibrium at any given point

Peak Amplitude

Minimum and maximum displacement

Peak to peak amplitude

+A to -A

Intensity

Power/Area

Pressure

Force/Area

The softest sound that a human can hear (IL)

10⁻¹²

The softest sound that a human can hear (SPL)

2(10⁻⁵)

Bel Equation

log₁₀(x/reference)

Decibel Equation (IL)

10log(x/10⁻¹²)

Decibel Equation (SPL)

20log(x/2(10⁻⁵))

Phon

Used to indicate an individuals perception of loudness

The sone scale is used to measure the _____ of loudness

growth

1 sone = ___db at 1000Hz

1

Sones Equation

2⁽ˢᴾᴸ ⁱⁿ ᵈᴮ⁻⁴⁰/¹⁰⁾

We do not hear vibrations directly, the vibration sets off a chain of moving _____

molecules

Molecules of the medium are disturbed by the initial _____

vibration

Air molecules immediately adjacent to object move in the _____ direction of the vibration and disturb molecules _____ to them

same, adjacent

Propagating medium must have _____ and _____

mass, elasticity

In longitudinal waves, the molecules do not keep traveling through the air but are pulled _____ to _____ _____

back, rest position

Areas of Condensation

When molecules are close together with increased density and pressure

Rarefaction

When molecules have increased distance between them with decreased density and pressure

When amplitude is higher, pressure is _____

higher

When amplitude is lower, pressure is _____

lower

In actuality, sound propagates in a _____ fashion in all directions

spherical

Wavelength

The distance between successive areas of condensation or rarefaction

Speed of sound in air

343m/s

Stiffness

The ability of an object to resist being deformed

Does greater stiffness equate to an increased or decreased speed?

Increased

Density

Space between molecules

Does greater density equate to increased or decreased speed?

Decreased

Transmission

The passing of sound through and between materials

Reflection

The bouncing back of a wave when it hits a surface

Absorption

The loss of sound energy when sound waves come into contact with absorbent materials

Diffraction

The bending of a wave as it moves around an obstacle

The amount of sound reflected depends on the _____ of the object it encounters

size

If object is _____ than wavelength, then sound will bend around it and move past it without being affected (diffraction)

smaller

If object is much _____ than wavelength, then sound will be mostly reflected

larger

Interference

Overlap of reflected soundwaves

Constructive Interference

Overlap of two points of rarefaction or two points of condensation resulting in a greater rarefaction or condensation

Destructive Interference

Overlap of rarefaction and condensation that results in lesser rarefaction or condensation

Impedance

The overall opposition to the propagation of sound

The greater the differences in impedances, the more sound will be _____

reflected

Impedance is composed of _____ and _____

resistance, reactance

Resistance is produced by particles rubbing _____ eachother

against

Reactance is a form of opposition produced by the _____ and _____ of the medium

mass, stiffness

Is resistance dependent on frequency?

No

Is mass dependent on frequency?

Yes

Is stiffness dependent on frequency?

Yes

Inverse Square Law

The further away someone is from a sound source, the softer the sound becomes

Does increased distance equate to increased or decreased intensity/pressure?

Decreased

Increased square law only applies to a _____ sound field

free

Reverberation Time

The time needed for a sound to decrease by 60dB

The three physical properties of a sine wave

Amplitude, Frequency, Phase

Frequency

Number of vibrations per a unit of time

Period

The amount of time needed for an oscillation to complete one cycle

Sinusoid

A curve representing periodic oscillations of a constant amplitude

Starting phase

When t=0

In-phase

Same phase

Out of phase

Different phases

Two forces that generate vibration

Inertia, Elasticity