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Definition
| The time required for the completion of one cycle of a periodic motion. |
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Definition
| The number of cycles per second. |
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Definition
| Any back and forth movement between two states. |
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Definition
| Mechanical oscillation with elasticity acting as the restoring force. |
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Definition
| The motion of an object in which changes in displacement, velocity, and acceleration are sinusoidal functions of time. |
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Definition
| A motion that repeats itself in regular intervals until stopped by an external force. |
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Definition
| A motion in thich the acceleration of the object is directly proportional but opposite in direction to the displacement of the object from its equilibrium position. |
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Definition
| A function representing changes of any physical quantity as a function of time. |
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Definition
| Process of conveying energy through space via a wave motion. |
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Definition
| Transfer of mechanic energy from one molecule to another. |
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Definition
| A substance that occupies a space; can be solid, fluid, or gas. |
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Definition
| Any event that causes a change in medium at a specific location. |
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Definition
| Waves in which the particles of the medium are displaced in the same direction as the wave propagation. |
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Term
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Definition
| Bunching of particles causing increased density. |
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Term
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Definition
| Spreading of particles causing decreased density. |
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Term
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Definition
| Particles of a medium are displaced in a directon that is perpendicular to the direction of wave propagation. |
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Definition
| Complex waves created when a mechanic disturbance arrives at a border between two media having different densities; combination of transverse and longitudinal waves. |
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Definition
| A disturbance in an elastic medium that propogated through the medium as a longitudinal wave; a stimulus that causes an auditory sensation. |
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Term
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Definition
| The rate at which energy propagates through a medium. |
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Term
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Definition
| The distance in space between two adjacent identical points of a propagating wave. |
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Term
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Definition
| The energy transferred from the vibrating source to the medium and propagates through the medium in the form of density changes. |
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Term
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Definition
| Very low frequency sounds that cannot be heard (below 20Hz). |
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Term
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Definition
| Very high frquency sounds that cannot be heard (above 20kHz). |
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Term
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Definition
| Tone with only one frequency. |
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Term
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Definition
| Tone with more than one frequency. |
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Definition
| Sounds where maginitude at different points in time can be predicted. |
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Term
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Definition
| Sounds where future behavior cannot be predicted; random. |
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Term
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Definition
| Random sound with acoustic properties that do not vary much over time. |
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Term
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Definition
| Noise content and intensity change randomly and noise properties cannot be predicted over time. |
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Term
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Definition
| The absolute difference between that phases of two waveforms with neither considered as a point of reference; maximum difference = 180 degrees. |
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Term
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Definition
| The relationship between the phase of one waveform and another where one is considered the point of reference. |
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Term
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Definition
| When two waveforms have the same frequency and phase. |
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Term
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Definition
| When two waveforms have the same frequency, but different phases. |
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Term
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Definition
| The magnitude of a waveform observed at any given time. |
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Term
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Definition
| The maximum/peak magnitude of a waveform. |
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Term
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Definition
| The whole range of magnitude changes within one period. |
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Term
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Definition
| The average value of the magnitude calculated across the whole period of a waveform. |
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Term
| Root mean square (RMS) magnitude |
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Definition
| Constant magnitude derived from the root of the mean of the squares of the instantaneous magnitudes calculated across the waveform's period. |
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Term
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Definition
| A mechanical property of an elastic object that describes its opposition to the change of its dimensions by an external force. |
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Term
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Definition
| A system that does not exchange its energy with the environment; no loss of energy. |
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Term
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Definition
| A system that loses part of its energy to the surrounding environment due to the effect of friction. |
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Term
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Definition
| The back and forth vibration of a system in which no additional energy is added once it is set into motion. |
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Term
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Definition
| The natural frequency at which a system will vibrate when left alone. |
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Term
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Definition
| A vibration in which a system is forced to vibrate by an applied force. |
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Term
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Definition
| The force that opposes the relative motion of two bodies in contact and causes the conversion of system energy into heat. |
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Term
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Definition
| The loss of energy in a vibrating system due to dissipation to the surrounding environment; causes a gradual decrease in amplitude. |
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Definition
| Very little system friction. |
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Term
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Definition
| Indicates the most rapid response to a sudden change of force without overshooting the equilibrium. |
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Term
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Definition
| A lot of system friction. |
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Term
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Definition
| Specifies time in seconds after which the amplitude of vibration decreases by ~63%. |
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Term
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Definition
| The overall duration needed to change from 10% to 90% of a waveform's peak. |
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Term
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Definition
| The time period during which a waveform has a relatively constant amplitude. |
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Term
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Definition
| The time needed for a waveform to change from 90% to 10% of its peak value. |
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Term
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Definition
| The dependence of the amplitude of vibrationof the frequency of the driving force. |
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Term
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Definition
| The sum of two or more simple vibrations. |
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Term
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Definition
| Any complex waveform is the sum of various sinusoids of varying amplitude, frequency, and phase. |
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Term
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Definition
| A vibration without a repeating pattern. |
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Term
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Definition
| Vibratory motion in which an object returns to the same point in space at equal periods of time during the motion. |
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Term
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Definition
| The process of combining several sine waves into a complex waveform. |
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Term
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Definition
| Whole-number multiple frequency components of a complex waveform. |
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Term
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Definition
| The largest common factor from a group of harmonically related components is equal to its fundamental. |
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Term
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Definition
| When the GCF of a set of harmonics is not present in the waveform. |
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Term
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Definition
| The concept that a periodic waveform repeats itself for an infinite amount of time. |
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Term
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Definition
| Random sequence of events resulting from the combination of a large number of unrelated frequencies. |
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Term
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Definition
| A brief, single event that ceases to exist after a very short time. |
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Term
| Complex inharmonic motion |
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Definition
| The sum of a finite number of frequencies that does not repeat its pattern within an observed period of time. |
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Term
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Definition
| The process of taking complex waveforms apart into individual components. |
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Term
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Definition
| Representation of a phenomenon as a function of time. |
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Term
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Definition
| A graphical representation of a complex waveform showing the waveform energy (amplitude) of the individual components (y-axis) arranged in order of frequency (x-axis). |
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Term
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Definition
| Representation of a phenomenon as a function of frequency. |
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Term
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Definition
| A spectrum that consists of one or more separate vertical lines. |
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Term
| Amplitude/frequency spectrum |
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Definition
| Displays the amplitude of various vector quantities associated with the components (velocity, force, displacement, etc.). |
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Term
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Definition
| A spectrum in which the energy of spread across a wide range of frequencies rather than at discrete sinusoidal components. |
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Term
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Definition
| Displays the power (energy) of the components. |
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Term
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Definition
| The points of the vibrating system at which displacement remains zero. |
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Term
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Definition
| The points at which the vibration magnitude is greatest. |
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Term
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Definition
| The specific vibration pattern of a vibrating system associated with each rosonance frequency of the system. |
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Term
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Definition
| The opposition to the flow of energy through a system and any change in its state. |
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Term
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Definition
| The opposition of a system to movement caused by friction. |
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Term
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Definition
| The opposition of a system to a change in its state by the system's ability to store energy and prevent its transfer to or from another system. |
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Term
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Definition
| The ability of the mass to store energy. |
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Term
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Definition
| The ability of the stiffnes to store energy. |
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Term
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Definition
| The wase with which energy travels through a friction element in the system. |
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Term
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Definition
| The ease with which energy travels through a stiffness element in the system. |
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Term
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Definition
| The ease with which energy flows through a mass. |
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Term
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Definition
| The ease with which energy travels through s spring element. |
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Term
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Definition
| The ease with which a system can vibrate due to an applied force. |
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Term
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Definition
| The practice of making the impedance of the source of power equal to the impedance of the load to transfer as much energy as possible from the source to the load. |
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Term
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Definition
| If mass reactance is greater than stiffness reactance. |
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Term
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Definition
| If stiffness reactance is greater than mass reactance. |
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Term
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Definition
| Sound wave will lose energy due to absorption by the medium and surrounding boundaries. |
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Term
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Definition
| The ability of a medium and its boundaries to absorb the energy of sound waves. |
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Term
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Definition
| The bouncing of sound waves off of a boundary. |
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Term
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Definition
| The bending of sound waves due to a change in the speed of sound propagation; caused by sound waves entering a different medium or changes in temperature. |
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Term
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Definition
| The original, incoming sound wave. |
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Term
| Total internal reflection |
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Definition
| A situation where 100% of the sound energy reaching a boundary is reflected back into the original medium. |
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Term
| Critical angle of incidence |
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Definition
| The smallest angle of incidence for which total internal reflection can occur. |
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Term
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Definition
| The effect of bending sound waves away from the ground when warmer air is nearer to the ground and colder air is above it. |
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Term
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Definition
| When colder air is closer to the ground and warmer air is above it, waves bend toward the ground. |
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Term
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Definition
| The time needed for a sound pressure to decrease 1000 times after the sound source ceases its operation. |
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Term
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Definition
| The reflected sound energy within an enclosed space. |
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Term
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Definition
| Closed spaces with highly reflective surfaces that do not absorb sound waves. |
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Term
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Definition
| Rooms with very soft walls, ceilings, etc. that absorb most of the sound energy. |
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Term
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Definition
| An area behind a boundary that the direct sound waves does not enter. |
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Term
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Definition
| The phenomenon of sound waves bending around objects and through openings in barriers. |
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Term
| Constructive interference |
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Definition
| An increase in amplitude of sound waves when two or more sund waves travel through the same space and are in-phase. |
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Term
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Definition
| A decrease in the amplitude of at least one sound wave when two sound waves travel through the same space and are out-of-phase. |
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Term
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Definition
| Slow, periodic amplitude fluctuations caused when two sine waves that are very close to each other in frequency interfere with one another. |
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Term
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Definition
| A space containing sound waves. |
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Term
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Definition
| The resulting vibrations in a sound pressure near the sound source; characterized by large and nonuniform maxima and minima in acoustic pressure that gradually disappear into a uniform signal with increasing distance from the source. |
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Term
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Definition
| The region of uniformly decreasing sound pressure (1/r) observed far away from the sound source. |
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Term
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Definition
| Sound field created by a sound source in an unbound space. |
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Term
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Definition
| Sound field in which sound propagation is not affected by objects or boundaries. |
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Term
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Definition
| Sound field where sound energy reflected from space boundaries dominates the sound energy propagating from the sound source. |
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Term
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Definition
| And area filled with sound energy from random reflections coming from all directions and in which all SPLs are the same. |
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Term
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Definition
| The distance from the sound source where the intensity of both fields is about equal. |
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Term
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Definition
| The ratio of intensity of a signal to the intensity of a noise. |
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Term
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Definition
| Additional length added to a mass of a vibrating system to determine the resonance frequency of a tube with an open end. |
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