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49 Cards in this Set
- Front
- Back
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Sound is a form of _________ and is a wave ____________ that ________ through any _________.
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energy
disturbance travels medium |
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How does sound differ from other vibrating motion?
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Sound waves in free air are 3 dimensional. Humans are accustomed to hearing sound propagated through air.
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What are the three properties necessary to produce sound waves?
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force (intensity of the wave)
vibrating mass elastic medium |
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Sound waves are produced by __________ ___________ because of the ___________ _______ that are created when molecules are packed closer together (__________) or spread further apart (___________) than normal.
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molecular vibration
pressure states compression rarefaction |
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As molecules undergo ___________, successive ___________ followed by __________ are passed along the lines of ____________ at the _________ of _______.
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oscillation
compressions rarefactions particles speed sound |
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What is the description of waves in terms of how often they move from maximum rarefaction to maximum compression and then return to their point of origin?
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frequency of the wave
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What is a force that moves a wave to its maximum amplitude?
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intensity of a wave
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What is a series of moving impulses set up by a vibration?
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wave
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What are the to-and-fro movements of a mass?
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vibrations
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What is the number of complete oscillations of a vibrating body per unit of time?
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frequency (pitch)
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In acoustics, what is the unit of measurement?
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cycles per second (cps)
or hertz (Hz) |
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What is the ability of a mass to vibrate at a particular frequency with a minimum application of external force?
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resonance
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What is the speed of a sound wave in a given direction?
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sound velocity
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What is the distance between the exact same point (in degrees) on 2 successive cycles of a tone?
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wavelength
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What is the relationship in time between 2 or more waves?
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phase
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What are waves behaving in simple periodic oscillation - the waveform of a pure tone showing simple harmonic motion?
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sine waves
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What is a sound wave made up of a number of different sinusoids, each with a different frequency? They produce the quality of a timbre of a sound.
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complex waves
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What is the amount of sound energy per unit area?
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intensity (loudness)
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Sound may be regarded objectively if we consider its waves in terms of what 4 things?
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frequency
intensity phase spectrum |
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Sound may be regarded subjectively if we consider it in terms of what 3 things?
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pitch
loudness interactions of signals producing masking or localization |
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What is the measurement for intensity?
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decibel
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The decibel is a ratio between what?
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2 sound pressures
or 2 sound powers |
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dB is a ____________ unit of measurement that expresses the ___________ of physical __________ relative to a specific __________ level.
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logarithm
magnitude quantity reference |
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The reason that dB is widely used is that human ears perceive sounds in __________ _________ instead of __________ _________ in both ___________ and __________ domain.
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logarithmic scale
linear scale frequency amplitude |
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What is the range of the dB?
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0 to 140
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What designates the lowest point in intensity that a person can perceive the stimulus?
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threshold
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If the stimulus is made less intense, we're below the individual's ___________. If you deliver the sound above the intensity, they begin to ______ it.
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threshold
hear |
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0db does not mean what?
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the absence of sound
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What is the unit of measure for intensity?
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watt per square meter
watt/m2 |
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What is the rate at which energy is consumed?
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the absolute measure of acoustic power in watts
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Intensity level only exists when there is a _________ given.
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reference
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As the intensity output increases, the ratio __________, raising the power of the _____ and ______________ the number of __________.
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increases
log increasing decibels |
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A difference of ten decibels means the sound is _______ as loud.
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twice
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What is the nominal threshold of human hearing?
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dB SPL
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Pressure = ?
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force per unit area
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unit of force = ?
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Newton (N)
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1 Newton = ?
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force that will accelerate
1kg (mass) 1 meter (distance) in 1 second (time) |
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What are units of sound pressure called?
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Pascals (Pa)
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1 Pa = ?
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N/m2
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By convention, it was decided that 0 dB SPL would equal how many Pascals?
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20 micro Pa
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What is the smallest, softest sound pressure variation required to produce a just audible sound to healthy young ears?
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20 micro pascals or
0.00002 Pa |
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This was designed as an instrument to test hearing sensitivity at different frequencies.
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audiometer
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What is the range of human hearing in Hz?
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20 to 20,000 Hz
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How do we define the amount of hearing loss that a person has?
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It is based on their threshold at a given frequency
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The human ear is not ________ _________ to all ___________. As you change _________, the _____ changes.
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equally sensitive
frequencies frequency SPL |
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What does ANSI stand for?
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American National Standards Institute
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What is the ANSI 2004 standard for audiometric testing?
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The difference between SPL and HL at 1000 Hz is 7.5 dB.
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What is used to designate an intensity level above the auditory threshold of an individual?
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dB sensation level (SL)
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If the patient had a threshold of 25 dB and you wanted to present a stimulus at 20 dB, what stimulus would you deliver?
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45 dB
20 dB sensation level 45 dB hearing level |
