Sound Waves Flashcards by Simone Van Huyssteen

Name 4 types of amplitude

Instantaneous Amplitude
Peak Amplitude
Peak to peak amplitude
RMS amplitude

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Period (T) is time taken to complete one full cycle of motion T/F

True

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Wavelength will_______ with and increase in pressure

decrease

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Give the symbol for speed of sound in air and value

33 600 cm/s

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Define sinusoidal motion / simple harmonic motion

Motion represented by a sine wave

It is simple, periodic, continuous oscillations

expressed as a Sine function.

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2 parameters for simple harmonic motion

Amplitude
Frequency
Phase

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Define science

Procedural pursuit of knowledge

that is evidence based

and is based on observations, investigations, theoretical explanations and experimentation.

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Is speech and hearing a science? Why?

Yes - pursuit of knowledge, uses systematic procedures and communicates knowledge to others for evaluation and replication, combines other sciences

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Define speed and velocity and speech

Speed: Distance travelled by an object over time

Velocity - distance travelled by a object over time and include directional information

Speech: Production of phonemes which forms words.

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How is speed and velocity used in speech

We look at the Velocity and speed of the different articulators

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Define Newtons first law of motion and give an example in speech and hearing.

An object in motion will remain in motion unless acted upon by an outside force. An object at rest will stay at rest unless acted upon by outside force.

Used to discuss vocal folds self-oscillation. Vocal folds start moving due to air pressure and airflow from the lungs. they will continue moving until acted upon by outside force (muscle movement)

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Define kinetic and potential energy. Relate it to speech and hearing

Kinetic energy is the energy of motion
Potential energy is the energy that is stored in an object. It can be stored i the stapes when it is pulled back ready to be released and transforming into kinetic energy as it is pressed on the oval window

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λ = c/f What does each respresent?

λ lambda wavelength
c speed of sound in air
f frequency

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Define phase angle of a sound wave

Shows the angle of sinusoidal motion compared to arbitrary position

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What is the unit for impedance

Ohm Ω

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What is the sound intensity (Ir) reference point value

10^-12 W/m^2

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Harmonic motion is expressed in ________ and _______

sines
cosines

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W=Fxd (what does each represent)

W Work
F Force
d displacement

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Where is a pendulum at equilibrium

In the middle

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What is newtons third law

For every action (force) there is an equal and opposite reaction (force)

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F = ma describe which newton law? What is each component

Second law: Net force on an object causes object to accelerate in same direction of force. a directly proportional to F, inversely to mass
F net force
m object mass
a accelleration

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Name 3 important properties of a transmitting medium

Mass
Elasticity
Density

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Define stiffness

Degree to which an object resists being deformed

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Define elasticity

Ability of an object to spring back to its shape when deforming forces are removed

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Unit for power

Watt (W)

Define speed of sound

Distance sound travels over a period of time and is a constant value Distance travelled per unit time and is a constant value

D = A sin (2πft + θ) What does each letter represent and its unit

D displacement (m) A amplitude (m) f frequency (Hz) t time (s) θ phase wave is at 2π circular origin

Define acceleration and deceleration

Acceleration: increase in velocity as a function of time Deceleration: decrease in velocity as a function of time

What is the two components of impedance

Resistance Reactance

10 dB = 1 Bel T/F

True dB = 1/10 bel

2 types of energy

Potential Kinetic

Unit for intensity level

dBIL

Sound pressure (Pr) reference point value

20 uPa

The shape of a complex wave is only dependent on amplitude T/F

False

Two loudness scales are the phon and tone scales T/F

False

Spectrogram only displays f and A

False

If a complex wave has the following frequency components 100, 200, 300, 500, 700. The first harmonic and first overtone is?

First harmonic 100 First overtone 300

Threshold of hearing is_____ a sound 10x as intense is______ dB

1000Hz assigned as 0 dB 10dB

Wavelength _______ when frequency decrease

increase

Define Sound pressure level

Difference between interest pressure and standard pressure - dB

The psychoacoustic correlate of intensity is pitch

False

Pressure = what divided by what

Force divided by area

Unit for Force

Newton

Give the unit for intensity, intensity level, power, sound pressure level

intensity W/m^2, intensity level dB IL, power watts, sound pressure level dB SPL

If signal level is more than noise level the signal to noise ratio is negative

False

What is waveform synthesis

Process of using superposition to combine several individual sine waves into single complex wave form

Pitch is measured by Mel Scale

True

Higher pitches are perceived as louder

True

Unit for work

J joules

Define work and power

Work = force exerted over a distance Power = rate at which energy is expended (work done per unit time)

Decrease in pressure if surface are increases

True

Define pressure and give formula

Force divided by area P = F/A kPa

Density is the number of molecules in a cubic inch air

True

Positive pressure is when density is lower than Patm

False - density is higher than Patm

T=1/f T=1/f Name symbols

T = period/ time taken to complete 1 cycle of motion f frequency/ cycles per second

Define phase relationship

Describes the difference between phases of two periodic waveforms through time

Define sound

Mechanical vibration from a sound source transmitted through elastic medium

Two classes of mechanical waves

Transverse waves Longitudinal waves

Speed of sound depends on

Elasticity Modulus of medium (K) and density (p)

What is instantaneous magnitude

Magnitude (displacement) of a waveform at any given moment

Maximum magnitude (highest displacement) = peak amplitude

True

Define friction

Force that opposes motion of 2 objects in contact

The effect of friction on a vibrating system is called______ resulting in _________

damping damped vibration

Forced vibration is when a system allowed to vibrate freely

False System not allowed to vibrate freely but forced by continuous force

Define resistance and reactance

Resistance - opposition to motion due to friction Reactance - opposition to motion due to mass & stiffness. Depend on F0

Define intensity and give unit

Power per unit area W/m2

If I = 10^-12W/m2 then the intensity is 0 dB IL

True

What is sound pressure and its unit

Force per unit area Pa

Two loudness scales

Phon and Sone scale

Loudness is the perceptual psychoacoustic correlate to intensity

True

2 Sound measurement scales

Sound level meter Filters

Pitch is the subjective (psychoacoustic) correlate to frequency

True

1000 Hz is the reference tone

True

The Mel scale compare tone against _______

reference tone

If 1000 mels = 1000 Hz 500 mels is a tone half as high in pitch as the reference tone 2000 mels means a tone is________

Twice as high as the reference tone

We hear bigger differences between two lower frequencies than between higher frequencies

False

Fundamental frequency in males and females

Males 120 Hz Females 220 Hz

What is a semitone

smallest distance between two pitches

All complex waves can be represented by the sum of a number of sine waves of differing amplitudes

Ture

What is a Fourier series

Series of sine waves added to form a specific complex wave (square wave)

Shape of a complex wave depends on

Frequency, magnitude and duration

What is fundamental frequency (F0)

Lowest repeating frequency of a complex tone

If a complex periodic wave consists of these frequency components, then... * 100, 200, 300, 400, 500 --- What is F0? * 100, 300, 500, 700, 900 --- What is F0? * 100, 300, 400, 500, 600 --- What is F0?

100 100

F0 = first harmonic F1

True

Second harmonic is 2x the fundamental frequency

True

Overtones is harmonics below F0

False - above

1st overtone = 2nd harmonic

true

Name x and y axis of a spectrum and waveform

Waveform: x time and y A Spectrum: x f and y A

Sound Waves Flashcards

(88 cards)