Bldg. Utilitues 3 Flashcards
A longitudinal pressure wave in air or an elastic medium, esp. one producing an audible sensation.
Sound wave
A disturbance or oscillation that transfers energy progressively from point to point in a medium or space without advance by the points themselves, as in the transmission of sound or light.
Wave
A graphic representation of the shape of a wave, obtained by plotting deviation at a fixed point versus time.
Waveform
The distance, measured in the direction of propagation of a wave, from any one point to the next point of the corresponding phase.
Wavelength
A particular point or stage in a periodic cycle or process.
Phase
The maximum deviation of a wave or alternating current from its average value.
Amplitude
The lowest frequency at which a vibrating element or system will freely oscillate.
Fundamental frequency
A vibration having a frequency that
is an integral multiple of that of the fundamental.
Harmonic
A range of wavelengths or frequency between two defined limits.
Band
The number of cycles per unit time of a
wave or oscillation.
Frequency
The Si unit of frequency, equal to one cycle per second.
Hertz
The predominant frequency of a sounds perceived by the human ear.
Pitch
The interval between two frequencies having a ratio of 2:1.
Octave
A surface of a propagating wave composed at any instant of all points having identical phases, usually perpendicular to the direction of propagation.
Wave front
An apparent shift in frequency occurring when an acoustic source and listener are in motion relative to each other, the frequency increasing when the source and listener approach each other and decreasing when they move apart.
Doppler effect
The velocity of sound traveling through air at approximately 1087 ft
0.3 kmps
The velocity of sound traveling through water at approximately 4500 ft
1.4 kmps
The velocity of sound traveling through wood at approximately 11700 ft
3.6 kmps
The velocity of sound traveling through steel at approximately 18000 ft
5.5 kmps
A subjective response to Sound Indicating the magnitude of the auditory sensation produced by the amplitude of a sound wave.
Loudness
A unit for measuring the apparent loudness of a sound, equal in number to the decibels of a 1000-Hz referenced sound judged by a group of listeners to be equal in loudness to the given sound.
Phon
A unit for measuring the apparently loudness of a sound, judged by a groups of listeners to be equal to the loudness a 1000-Hz reference sound having a intensity of 40 decibels.
Sone
A curve representing the sounds pressure level at which sounds of different frequencies are judged by a group of listeners to be equally loud.
Equal loudness contour
A unit for expressing the relativepressure or intensity of sounds on auniform scale from O for the leastperceptible sound to about 130 for theaverage threshold of pain. Abbr.: dB
Decibel
The sense by which sound is perceived, involving the entire mechanism of the internal, middle, and external ear and including the nervous and cerebral operations that translate the physical operations into meaningful signals.
Hearing
The level of sound intensity is high enough to produce the sensation of pain in the human ear, usually around 130 dB.
Threshold of pain
Physical or mental weariness caused prolonged exposure to loud noises.
Auditory fatigue
An increase in the threshold feasibility, at specific frequencies,caused by normal aging, disease, or injury to the hearing organs.
Hearing loss
The minimum sound pressure capable stimulating an auditory sensation,usually 20 micropascals or zero dB.
Threshold of hearing
The amount of acoustic energy
radiated by a source per unit time,expressed in watts.
Sound power
The acoustic power of a source measured on the decibel scale, equal to 10 times the common logarithm of the ratio of the acoustic power to reference power, usually 10^-12 watts.
Sound power level
An electrical instrument for measuring sound pressure levels. To compensate for the way we perceive the relative loudness of different frequencies of sound, there are three networks: A, B,and C. These networks weight the recordings for different frequencies and combine the results in a single reading. The A-network scale, in dBAunits, is most commonly used since itdiscriminates against the lowerfrequencies, as does the human ear atmoderate sound levels.
Sound level meter
The rate at which acoustic energy flows through a medium, expressed in watts per square meter.
Sound intensity
Sound intensity measured on the decibel scale, equal to 10 times the common logarithm of the ratio of the sound intensity to a reference intensity, usually 10^-12 watts per square meter (10-16 watts per square centimeter.)
Sound intensity levels
The exponent indicating the power to which a base number must be raised to arrive at a given number.
Logarithm
A logarithm having a base of 10.
Common logarithm
A range of frequencies from 15 Hz to 20,000 Hz audible to the normal human ear.
Audio frequency
The difference between the actual pressure at any point in the field of sound wave and the static pressure at that point, expressed in pascals.
Sound pressure
Sound pressure measured on the decibel scale, equal to 10 times the common logarithm of the ratio of the sound pressure to a reference pressure, usually 20 micro pascals.
Sound pressure level
