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47 Cards in this Set
 Front
 Back
is related to the distance that the soundproducing body (the vibrator) moves during vibration. The greater the distance from the point of rest, the greater the _______.

Amplitude


the excursion distance at any point in time

instantaneous amplitude


greatest point of displacement

peak amplitude


statistical average of all amplitudes at all times

RMS (rootmeansquare) amplitude


vibration that is not repeatable over time. Sounds produced by this are generally classified as noise

aperiodic vibration


an instrument for measuring hearing thresholds. Hearing measurements are typically obtained for both pure tone and speech signals. The stimuli produced are presented to the listener through a pair of earphones, a bone conduction vibrator, or loudspeaker. The level of the stimulus is controlled by the examiner until a threshold level is obtained. The results are plotted on an audiogram.

audiometer


the frequency difference between the lower and upper noise band limits. More generally, however, the ______ of any device or system is the range of frequencies within which the performance of the device or system remains above a specified level.

bandwith


a periodic sound wave that consists of a fundamental frequency combined with other sine wave components at different frequencies

complex tone


occurs when the air particles are pushed together; this condition increases the resting air pressure

compression


the property of a medium or a body that enables it to return to its original shape after it has been deformed; may be considered a restoring force; the greater the _______ the more resistant the medium or body to deformation

elasticity


the number of complete cycles that a periodically vibrating source passes through in a 1second time period; is expressed in Hz

frequency


the lowest frequency component in a complex tone

fundamental frequency


pure tone components of a complex tone that are integral multiples of the fundamental frequency

harmonics


a complex sound wave that consists of a fundamental frequency together with other pure tone components at integral multiples of the fundamental

harmonic series


the unit of measurement for frequency; named in honor of an important German physicist Heinrich ______. It is synonymous with the formerly used expression cycles per second (cps)

Hertz


The ability of a body to continue doing what it has been doing; If the body is at rest, it will tend to remain at rest. If the body is in motion, it will tend to remain in motion

inertia


the condition in which two waveforms of the same frequency coincide exactly in their phas angles (phase difference). That is, both waves correspond exactly in their minimums and maximums at the same instants in time

in phase


the amplitude of a vibratin source at any instant in time

instantaneous amplitude


the amount of acoustic energy that passes through a unit of area in a given time span. May be measured in units of power or pressure directly, but more frequently it is measured in decibels, which are logarithmic ratios

intensity


noise that is restricted in its frequency range. The spectrum is continuous (no gaps), and the frequency components are all of equal amplitudes. Like white noise, there is no regard to phase of the pure tone components

narrowband


any undesired sound

noise


those frequencies below or above which there is no apprecialbe noise energy. In practice, the band limit frequency is often taken as the point where the energy content is 3 dB below the average energy in the pass band

noise band limits


the maximum instantaneous displacement of a vibrating source from its point of rest

peak amplitude


the amplitude of a vibrating source, measured from the maximum positive peak to the maximum negative peak

peaktopeak amplitude


the time it takes to complete one cycle of vibration. is defined as 1/f, where f is the frequency of vibration. The ______ of a 1000 Hz tone is then 1/1000 or one onethousandth of a second

period


vibration that repeats itself regularly over time; both pure tones and complex tones are examples of this

periodic vibration


that portion of a cycle (Hz) which has elapsed at a given instant in time, relative to some arbitrary starting point. Because of the relation between simple harmonic motion (SHM) and projected circular motion, the phase angle may vary between 0 degrees and 360 degrees

phase angle


the difference inphase angles between two periodic waveforms at any instant in time; relative to some arbitrary starting point. For example, if two 1000Hz tones are started onefourth cycle apart, their _____ __________ will be 90 degrees

phase difference


the condition in which two waveforms of the same frequency are exactly onehalf of a cycle (180 degrees) out of ophase. That is, when one wave is at its maximum value, the other is, at teh same instant, at its minimum value. Thus, the two waveforms always assume opposite but equal positions relative to the baseline

phase opposition


a sound with a definite tonal quality. The waveform of the vibrating body that produces this is a sine wave. The frequency of this represents the completed number of cycles the vibrating source passes through in a 1sec time period

pure tone


occurs when air particles are separated. this condition results in a decrease in the resting air pressure

rarefaction


represents the effective amplitude of the source. mathematically, this is equal to the square root of the mean of all the squared instantaneous amplitudes. For the case of a sine wave, this equals .707 times the peak amplitude

rootmeansquare


a symmetrical to and fro motion of a body over a rest position. When the amplitudes of the body are plotted as a function of time, the resulting pattern is a sine wave. Pure tones are produced by this

simple harmonic motion


an instrument that measures sound levels in decibels with a specific reference of .0002 dyne per cm squared; it consists of a microphone, amplifier, output meter or digital display, adn several frequencyweighting networks. The purpose of the networks is to simulate the response characteristics of hte normal human ear

sound level meter


a plot showing the frequencies and amplitudes of the individual components of the wave. It is also used to denote a range of frequencies that possess a common characteristic, such as the audiofrequency spectrum

spectrum


a spectrum in which the energy in the wave is at only one or more discrete frequencies (a pure or a complex tone)

line spectrum


a spectrum in which there is a continuous and unbroken band of frequencies

continuous spectrum


the character of a musical tone that distinguishes one musical instrument from another; it depends upon the relative intensities of the harmonic frequencies produced by each instrument

timbre


a plot that shows the instantaneous amplitudes of the signal over time

waveform


consists of a continuous spectrum across the auditory range. Although the amplitudes of all the frequency components that comprise the noise are equal, there is no regard to the phases of the frequency components

white noise


the distance in space between two corresponding points (phases) in two consecutive cycles in a periodic sound wave; it is related to the velocity of sound and frequency by the formula "wavelength = velocity/frequency"

wavelength


graphic representation of a signal

sine wave


process whereby friction causes sound to weaken and eventually stop vibrating in a medium

damping


more than 1 wave together

complex wave


unit value used to measure sound

dyne


logarhythmic scale used to measure sound

decibel


amount of intensity at an individual frequency

audiometric zero
