SLHS 305 (Audiology) Exam #2

What is Longitudinal wave motion? Hint: What's the air particle doing in relation w/ a wave? What system is being used?

*air particles is moving horizontal or parallel motion to wave motion *uses spring mass system * how we are perceiving sound

What is Transverse wave motion? Hint: What's the air particle doing in relation w/ a wave?

*air particles is moving up and down or perpendicular to wave motion

What happens when frequency is above resonance in mass and compliant reactance graph? Hint: Z _______; amplitude of vibration ______; ________ dominant

-Z increases - Amplitude of vibration decreases - Mass dominant (Xm>Xc)

What is pendular motion dictated by?

Interaction between mass and surface

What makes the spring mass system stop?

Interaction between mass and surface

Is mass equivalent to weight?

No

*density decrease (when concerning the movement of air particles) *(air particles are wider; the gap between compressed air particles)

Rarefaction

Complex Wave : Triangular wave *identical starting phases * similar to square wave but ramp is steeper * _____ integer multiple * rejection rate: ______ dB per octave step

odd; -12

Frequency of vibratory motion (f) *The number of cycles per second (cps). *_____ cycle - movement from equilibrium to maximum displacement, back to equilibrium, to maximum displacement in the opposite direction, then back to equilibrium. *Unit of measure = _________ - 1 Hz = 1 cps

one; Hertz (Hz)

Transformation of energy (Pendular Motion) 1. Motion ultimately ceases because of frictional resistance. 2. Frictional resistance is a force that _______ motion and limits velocity. 3. _________ transformed to thermal energy (heat). 4. Result is damping or ________ vibration. - reduction in vibration due to opposing force - decrease in displacement as a result of an opposing force *1-4 leads to ______ in motion * perfect sine wave = _____ decrease in displacement over time

opposes; kinetic energy; damped; decrease; no

Acoustic impedance *If a system engages in simple harmonic motion, then it is moving as free vibration at is own natural frequency (f nat). *These vibrations will continue until a force acts in _______ of them. * Forces exist that oppose or impede motion: __________ (Z). * Total impedance has two components 1. Resistance (R) 2. _________ (X) -mass reactance (Xm) - complaint reactance (Xc)

opposition; impedance; reactance

Band-_____ filter *Passes energy between some fL and fu, attenuates energy below fL and above fu * overlapping of low-pass and high-pass filters **look at lecture #6 pg 5 for more info

pass

Transformation of energy (_______ Motion) - _____ is not depleted, it is either transferred or transformed. - Potential energy (PE) - ______ energy - ______ energy (KE) - energy of motion.

pendular; energy; stored; kinetic

*High-pass filter *Passes energy above some fL, attenuates energy below fL -high frequencies pass _____ some _____ cutoff frequency *Two parameters: fL (________ cutoff frequency) and attenuation rate * bandwidth of high-pass filter _____ be determined

above; lower; lower; can't

Diffraction A: Sound wave encounters a barrier. Some energy is reflected back. Wave fronts scatter or ______ around the obstacle. Wave fronts then reform and continue after the barrier. Loss of acoustic energy after the barrier and when some energy is reflected back B: Sound wave encounters a hole in the barrier. Some energy is reflected back. Portions of the wave pass through and then reform as the ______ wave.

bend; plane

Refraction A: Sound travels in no wind, wave fronts are not ______. B: Wind speed increases higher above ground. C: Sound travels against wind and wave is refracted _____. D: Sound travels ______ wind and wave is refracted down.

bent; up; with

Reflection from convex surfaces *Obstacle surface is convex toward the source of sound. *Reflected rays _______ and sound energy is scattered.

diverge

What is the conversion from Hertz (Hz) to megahertz (MHz)?

divide by 1,000,000

What is the conversion from microsecond to seconds?

divide by 1,000,000

What is the conversion from microsecond to milliseconds?

divide by 1000

System Tuning: Broad Tuning * good ______ of sound *goal is to take in _______ frequencies - Higher R (_______) - _______ damping - _______ free vibrations - Vibrate over a wide range of frequencies *passes more efficiently in different frequency Ex: telephone

receiver; many; resistance; more; brief

Band-_______ filter *Rejects energy between some fL and fu. *non-overlapping low-pass and high pass filter **look at lecture #6 pg 5 for more info

reject

Periodic waves - A wave that ______ itself over time. - Also called a period time function *A complex periodic wave is _______ sinusoidal

repeats; not

Speed of Sound *Speed of sound = 331 m/s at ______ level, and if the temperature = 0 degrees C. *Speed of sound ______ by .61 m/s for each 1 degree increase in temperature. *When we change the medium, speed of sound ______ *Elasticity component increases more when density component increases

sea; increases; increases

Simple harmonic motion 1. Spring-mass system undergoes _____ harmonic motion. 2. Simple harmonic motion is characterized as projected uniform ______ motion.

simple; circular

Sinusoidal motion *Simple harmonic motion can be called _______ motion. *Projection of sinusoidal motion is called a _____ wave or sinusoidal wave.

sinusoidal; sine

Frequency of vibratory motion (f) 1. Frequency of vibration of the source is determined by characteristics of the ________. 2. Frequency of vibration of air particles is the ______ as frequency of the source.

source; same

Dimensions of the sine wave - wavelength * Wavelength (λ) relates frequency and speed of sound. *λ = s/ f *λ = distance traveled during one period; unit of measure is meters * s = ____________; unit of measure is meters per seconds (m/s) * f = ____________; unit of measure is cycle per second (c/s)

speed of sound; frequency

Four steps of the __________ system 1. Displace the mass. 2. Spring is compressed. 3. System is set into ________. 4. System engages in simple, harmonic, or sinusoidal motion.

spring mass; vibration

Movement of air particles When a tuning fork is _____, the tines are set into _________. This motion sets the air particles around the tines into motion. There is a _____ and thinning of air particles. *air particles give a domino effect

struck; motion; crowding

-The log of the ratio absolute intensity (Ix) and relative intensity (Ir). -Can be positive or negative

the bel

a quantity expressed in seconds (s), minutes (min), hours (hrs), etc.

time

*A plot of change in amplitude of displacement (x) over time.

waveform or sine wave

What is an aperiodic wave?

- A wave that lacks periodicity. *A wave with no fixed pattern - Vibratory motion is random and it sometimes is called a random time function. Ex: white noise or the /sh/ sound

What happens when frequency is below resonance in mass and compliant reactance graph? Hint: Z _______; amplitude of vibration ______; ________ dominant

- Z increases - Amplitude of vibration decreases - Compliance dominant (Xc > Xm)

What are the 5 parameters of filters? Hint: fc; fu; fL; Δf; _____ rate *which ones can we dictate and which ones depends on whether we know the frequencies

1. Center (natural) frequency, fc 2. Upper cutoff frequency, fu 3. Lower cutoff frequency, fL 4. Bandwidth, Δf 5. Attenuation (rejection) rate * 1-3 we can dictate * 4 & 5 depends on whether we know the frequencies

What are the 5 derived physical qualities?

1. Displacement (x) 2. Velocity (c) or (v) 3. Acceleration (a) 4. Force (F) 5. Pressure (p)

What are the 5 dimensions of sine waves? Hint: F.P.A.P.W

1. Frequency 2. Period 3. Amplitude 4. Phase 5. Wavelength

What are the 4 types of filters?

1. Low-pass 2. High-pass 3. Band-pass 4. Band-reject

f0 Harmonic Octave 250 250 250 500 500 750 1000 1000 2000 * To get 750 (which is ____rd harmonic), you add _____ * Octave - Refers to a doubling (2f) or halving (1/2f) of frequency. - 2000 Hz is one octave _____ 1000 Hz and two octaves above _____ Hz. - 500 Hz is one octave below _____ Hz.

3; 250; above; 500; 1000

What is a decibel?

A decibel is 1/10 of a bel.

What is weight?

A gravitational force

To vibrate, a sound source must have two properties... What are they? The medium must have what two properties?

A. Mass (m) B. Elasticity (E)

To transmit sound, what must a medium be capable of?

Must be capable of being set into vibration.

*The time-rate change in velocity over time - (Vector quantity) a =Δc / t = (c2 - c1) / t *unit of measure: meters per seconds squared (m/s^2)

Acceleration (a)

What is the rule of inertia?

All bodies remain at rest or in a state of uniform motion unless another force acts in opposition.

________ reactance (Xc) *Measured in ohms (Ω). *Xc= 1 / 2πfc *Xc is inversely proportional to frequency. *as f ________, Xc ( ________ component: stapedus and tensor tympani [muscle of middle ear]) increases **look at graph on pink sticky note

Compliant, decreases; stiffness

*density increase (when concerning the movement of air particles) *(air particles are close together)

Compression

__________________: less motion of whatever system - Oscillating systems encounter opposition to motion: friction or frictional resistance. - Friction limits velocity. - Amplitude of vibration diminishes over time. - Vibrations are damped. * every time we damp, amplitude _______

Dampening; decreases

What is the conversion from milliseconds (ms) to seconds (s)?

Divide by 1,000

What is the conversion from Hertz (Hz) to Kilohertz (kHz)?

Divide by 1000. *1000 Hz = 1 kHz.

Energy Principle 1. ______ is something that a body/system possesses. 2. Body/system must _____ a supply of energy in form of force or pressure 3. Energy is something that can produce a ______ in matter.

Energy; receive; change

*A push or pull, the product of mass (m) and acceleration (a) *F=ma (version of Newton's 2nd Law is a =F/m) *Object has a mass (inertia) which opposes change in motion, (F) is applied to overcome inertia *Unit of measurement is newton (N)

Force (F)

*Rate of vibratory motion *the rate, in Hz, at which a sinusoid repeats itself. * how many cycles completed

Frequency (f)

What are the two characteristics of sound/sine wave propagation?

Frequency and period

The amount of matter present. Applies to gases, liquids, and solids

Mass

______________ reactance (Xm) *Measured in ohms (Ω). *Xm = 2πfm *Xm is directly proportional to frequency * as frequency goes up, Xm goes _____ > the system impedes _____ frequency **look at graph on pink sticky note

Mass; up; high

What is the conversion from Kilohertz (kHz) to Hertz (Hz)?

Multiply by 1,000

What is the conversion from seconds to milliseconds (ms)?

Multiply by 1,000. *2 s = 2000 ms.

What does 0 dB mean?

Not absence of sound, less than absolute threshold

Dimensions of the sine wave - amplitude *amplitude's unit of measure = _______ * amplitude = amount of distance from equilibrium 1. Instantaneous amplitude - have to be given time 2. Maximum amplitude 3. Peak-to-peak amplitude - max top + max bottom 4. Root-mean- square (rms) amplitude - RMS is standard deviation of all instantaneous ____________. - The square root of the mean of the squared deviations of instantaneous values - rms = A(.707) - unit of measure is ______ *** look at lecture #2 bookmark 2

Pascal (Pa); amplitudes; Pascal (Pa)

*Rate of wave propagation *how much time it takes to complete one cycle

Period (T)

*bending of sound waves due to a change in speed of propagation. *When a wave encounters an obstacle offering a large impedance, the wave is reflected with no change in speed of propagation.

Refraction

Summation of sine waves: ________ waves *Sine waves with identical starting phases. *Each component is an odd integer multiple of f0 (_____________). *_________ periodic wave *rejection rate : ____ dB per octave step > seen in ________ spectrum

Square; fundamental frequency; complex; -6

Dimensions of the sine wave - phase *__________ phase - the angle, in degrees, at the moment rotation begins. *____________ phase - angle of rotation at a specified moment in time.

Starting; instantaneous

T of F The inverse square law *Intensity is energy / s / m2 (energy per second per meter squared). * If power remains constant and the surface area increases, intensity must decrease. *Inverse square law only holds strictly in a free, unbounded medium with no obstacles. -If a sound wave encounters an obstacle, it will be: reflected, refracted, diffracted, or absorbed

T

T of F Waveform and spectrum 1. Waveform - plot changes in some variable as a function of time. 2. Amplitude spectrum - a graphic alternative to the waveform. Also called the amplitude spectrum in the frequency domain. 3. Phase spectrum defines the starting phase as a function of frequency. Amplitude and phase spectra describe the waveform completely in the frequency domain.

T

T or F * Frequency-selective filters A: Amplitude spectrum of input signal. - present/send a broad band of frequencies to the system B: System transfer function. - only allows certain frequencies to pass through system C: Amplitude spectrum of output signal. - outcome

T

T or F *don't know what we are studying >Use broad tuning in order to receive a broad arrange of frequency * use narrow tuning when you know what range of frequency you are studying

T

T or F Attenuation rate in dB/octave 1. The rate at which energy for frequencies < fc or > fc is rejected (attenuated). 2. The slope of the filter curve, expressed in dB/octave. 3. Rejection rate or roll-off rate.

T

T or F Spherical waves *Compressions form a spherical shell that is called a wave front. Wave front moves outward from the sound source. *At some distance from the source the spherical wave becomes a plane wave.

T

T or F Waveform and spectrum *Aperiodic waveform has a continuous amplitude spectrum. A continuous amplitude spectrum has energy present at all frequencies within certain lower and upper frequency limits.

T

T or F: A system outside of resonance takes what steps to get back to equilibrium? 1. Impedance 2. Damping

T

Does a 1000 Hz tone travel faster or slower than 500 Hz tone?

They travel at the same speed b/c frequency isn't included in speed of sound

Newton's ____ Law of Motion -With every force there must be an ____ and opposite reaction force -For ______ motion, elasticity is the reaction force to inertia. *What is the reaction force to inertia for vibratory motion? > _______

Third; equal; vibratory; elasticity

Bandwidth (Δf) *Δf defines the range of frequencies passed by the filter **Δf=fu (_________) - fL (_________) *Δf quantifies how narrowly or broadly tuned the filter is **look at lecture #6 pg 3

Upper cutoff frequency; Lower cutoff frequency

_____ cutoff frequency (fu) *That frequency above fc for which amplitude of response is ____ dB less than response at fc The 3 dB down point or the half- power point **look at lecture #6 pg 3

Upper; 3

* The amount of displacement per unit time *The time-rate of displacement. - (Vector quantity) *how long and in what direction *speed does not equal (c) b/c speed= distance/time and c = displacement (x) / time (t) *unit of measure: meters per second; centimeter per second; miles per hour

Velocity (c)

_______ Motion/ Tuning Fork Motion -The interaction of two opposing forces: inertia and elasticity. -the opposition of two forces is consistent w/ Newton's ______ law * when you look at a tuning fork, x = equilibrium/ no motion during x; y = maximum displacement _____; z = maximum displacement ______ *When you strike a tuning fork .... -@ 1st strike, there is maximum displacement of x & y > after the 1st strike, the displacement of x & y will _______ -When you strike a tuning fork, it displaces to y > set to vibration > passes through equilibrium > goes to z(maximum displacement) **( one cycle = ____ to x to __ to x to y)

Vibratory; third; inward; outward; decrease; y; z

Do sine waves decrease in displacement over time?

Yes

Lower _____ frequency (fL) *Frequency below fc for which amplitude is 3 dB less than at fc **look at lecture #6 pg 3

cutoff

Sound wave Motion *Sound is characterized by propagation of _______ changes through an _______ medium. *There are other physical quantities that need to be considered.

density; elastic

A ___________ is a quotient or product of two fundamentals, or of fundamental and derived, physical quantities. 1. Displacement (x) 2. Velocity (c) or (v) 3. Acceleration (a) 4. Force (F) 5. Pressure (p)

derived quantity

when a wave bends around an obstacle.

diffraction

Types of wave motion *Classified by _______ of vibration of medium or the direction of wave propagation. *Two types: -Transverse -Longitudinal

direction

*____________(x): A change in position. - A _____ quantity that incorporates both magnitude and direction. - Contrast with a scalar quantity that has only _________(e.g., mass)

displacement; vector ; magnitude

A property that enables recovery from distortion of shape or volume. -b/c of E, systems will come back to rest or its equilibrium *ability for either sound generator, sound medium, or sound receiver to recover from distortion ex: vocal folds abduct

elasticity (E)

Spring-mass system *maximum displacement > goes/pass through ________ > goes to max displacement in ________ direction > goes through equilibrium *________ resistance is what brings mass to equilibrium (or its motion comes to a stop) in spring mass system -interaction w/ mass and the surface ex: _______ surface = longer motion

equilibrium; opposite; frictional; smoother

Summation of sine waves: sawtooth wave *Sine waves with identical starting phases. *The components are odd and ______ integer multiples of f0 (__________). *complex _________ wave *rejection rate : ____ dB per octave step > seen in amplitude spectrum

even; fundamental frequency; periodic; -6

** Newton's _____ Law of Motion -Magnitude of inertia is directly proportional to the mass, and as a result is measure of inertia. *things that are at rest will stay at rest and things that are in motion will stay in motion unless another force acts in opposition - higher mass = ___ inertia - _____ mass = lower inertia

first; higher; lower

Reflection from concave surfaces *Obstacle surface is concave toward source of sound. *Reflected waves converge, sound energy is concentrated at a ______ point where energy intensity is _______. * acoustic energy will sound louder @ focal point

focal; maximal

Magnitude of damping *Magnitude of displacement depends on ______ applied. *Duration of vibration depends on magnitude of damping.

force

Reactance (X) *Forces that oppose motion in a _____ selective way: frequency dependent. *Reactance depends on _____ and compliance of the system. *Both mass and compliance oppose, or impede, motion but in ______ ways. *Energy is _____.

frequency; mass; opposite; stored

Two components of X: Xm and Xc *When one reactance component stores energy, the other _____ energy. *They are 180 degrees out of phase with one another. *They act in ______ to one another.

gives up; opposition

What makes pendular motion stop?

gravity

Sound wave traveling and temperature A: Early morning - warmer air is ______ and has less density. Less density leads to increased speed of sound. Wave fronts are refracted downward. B: Midday - warmer air is lower and sound waves are refracted ______.

higher; upward

Spring-mass system *Hooke's Law - magnitude of restoring force is directly proportional to magnitude of displacement. - ________ x = increase Fr (________) *Fr = -kx , where k is the stiffness constant of the spring, _____ is the displacement, and the [-] is opposite direction *The direction of the restoring force (Fr) is opposite *the more further you push object forward, the object wants to go in _______ direction

increase; restoring; x; opposite

Resistance (R) *Friction, or frictional resistance, occurs: _____ energy is transformed into thermal energy. *Resistance measured in ohms (Ω). *Resistance is ______ of frequency. -fluid in cochlea is the anatomic system that is an acoustic _______ *Energy is dissipated ( _________ ).

kinetic; independent; impedance; scattered

a measure of distance, the amount of spatial separation between two points

length

System Tuning: Narrow Tuning *good ____ of sound - _______ R (resistance) - Less damping - Longer free vibrations at fnat > _____ frequency * goal is to generate pure tones b/c it's ____ to pure tones Ex: tuning fork

less; longer; generator; similar

* _______ -pass filter -Passes energy below some fu (____ cutoff frequency), attenuates(_____) energy above fu -Two parameters: fu and attenuation rate ** low frequencies pass threw the upper cutoff frequency ex: if fu=250 Hz, 100 Hz can pass through it b/c it's lower than 250Hz ?What is the bandwidth of a low pass filter when fu= 250 Hz? _______

low; upper; reduce/reject; Bandwidth = 250Hz

Harmonic relations - In a harmonic relation each sinusoid in the series must be an integer multiple of the ______ in the series. - Each of the components is called an harmonic. - First harmonic = _________ frequency (f0) - Second harmonic = ______ overtone

lowest; fundamental; first

the quantity of matter present, defines the magnitude of inertia

mass

Center/natural/resonant frequency (fc) *Frequency corresponding to maximum amplitude of vibration. *Xm (________) = Xc (_______) *Z is minimal at fc **look at lecture #6 pg 3

mass reactance; compliant reactance

Mass and compliant reactance *If Xm (_______) = Xc (_________), X (_______) =0, then Z (impedance) = R (resistance). *Impedance is ________ + Amplitude of vibration is largest = Resonance or natural frequency. **look at graph on pink sticky note

mass reactance; compliant reactance; minimal

The principle of resonance (the frequency to which objects vibrate ____ easily) *Periodic force is applied to an elastic system. *System is forced to vibrate at frequency of applied force, not at the fnat of the system. *The closer the frequency of the applied force to the natural or resonant frequency, the _____ the amplitude of the vibration (loudness increases). ex: 500 Hz to 1500 Hz * gradually gets louder and then once frequency goes ____ resonant frequency, it gets lower

most; greater; above

What is the conversion from megahertz (MHz) to Hertz (Hz)?

multiply by 1,000,000

What is the conversion from seconds (s) to microsecond ?

multiply by 1,000,000

Absorption *infinite impedance = ____ absorption - Opposition to sound transmission will exist at any boundary where the impedances differ. *If impedance is infinite, intensity of reflected wave will equal intensity of incident wave. *Ir =Ii *If impedance is not infinite, some sound energy will be absorbed by the new medium. - Intensity of the reflected wave will be _____ than intensity of incident. *Ir <Ii

no; less

Reflection of sound waves *With no obstacle, wave fronts would continue to sound source. Because of the obstacle, sound wave is reflected back to the source with ____ change in speed of propagation and energy is the ____ (no energy is lost)

no; same

Complex waves - A complex wave is any sound wave that is _____ sinusoidal. - Complex wave consist of a series of simple sinusoids that can ______ in amplitude, frequency, and phase. -Called a Fourier series. - A Fourier series can be derived by a process called Fourier analysis.

not; differ

Force per unit area * p = F /A * Units of measure for pressure N/m2 dyne/cm2 ** 1 pascal (Pa)

pressure (p)