Sound Waves Flashcards
Name 4 types of amplitude
- Instantaneous Amplitude
- Peak Amplitude
- Peak to peak amplitude
- RMS amplitude
Period (T) is time taken to complete one full cycle of motion T/F
True
Wavelength will_______ with and increase in pressure
decrease
Give the symbol for speed of sound in air and value
c
33 600 cm/s
Define sinusoidal motion / simple harmonic motion
Motion represented by a sine wave
It is simple, periodic, continuous oscillations
expressed as a Sine function.
2 parameters for simple harmonic motion
Amplitude
Frequency
Phase
Define science
Procedural pursuit of knowledge
that is evidence based
and is based on observations, investigations, theoretical explanations and experimentation.
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
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.
How is speed and velocity used in speech
We look at the Velocity and speed of the different articulators
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)
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
λ = c/f What does each respresent?
λ lambda wavelength
c speed of sound in air
f frequency
Define phase angle of a sound wave
Shows the angle of sinusoidal motion compared to arbitrary position
What is the unit for impedance
Ohm Ω
What is the sound intensity (Ir) reference point value
10^-12 W/m^2
Harmonic motion is expressed in ________ and _______
sines
cosines
W=Fxd (what does each represent)
W Work
F Force
d displacement
Where is a pendulum at equilibrium
In the middle
What is newtons third law
For every action (force) there is an equal and opposite reaction (force)
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
Name 3 important properties of a transmitting medium
Mass
Elasticity
Density
Define stiffness
Degree to which an object resists being deformed
Define elasticity
Ability of an object to spring back to its shape when deforming forces are removed
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
