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46 Cards in this Set
- Front
- Back
Sound Wave |
longitudinal pressure wave in air or an elastic medium especially one producing an audible sensation |
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Acoustics |
the science that studies the waves that are conducted through matter due to the motion of the matter |
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Architectural Acoustics |
the study of acoustics when the air is contained in a room |
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frequency |
the rate at which the source produces sound waves ; the number of times per second that a vibrating body completes one cycle of motion. |
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hertz , 1Hz= 1 cps (cycle per second ) |
unit for frequency |
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true |
True or False: bass sounds have low frequencies |
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false |
True or False: treble sounds have low frequencies |
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20-20,000 Hz |
a healthy , young person can hear sounds with frequencies from roughly _________. |
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300-3000 Hz |
The sound of human speech is mainly in the range ______. |
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Architectural Acoustics |
the effect of building design on the control of sound in buildings |
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Engineer |
Responsibilities: Keep the sound from mechanical equipment at an acceptable level |
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Manufacturer |
Responsibilities: designing machinery for quiet operation |
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Architectural Consultant |
Responsibilities: Can point out possible solutions to provide satisfactory noise control |
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Architect |
Responsibilities: recognize a potential noise problem in a proposed building & take steps to solve it |
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Sound |
produced by vibrating objects & reaches the listener's ears as waves in the air or other media |
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Sound level |
the measure of the strength of sound |
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decibels (dB) |
unit of Sound level |
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true |
true or false: the shorter the wavelength, the higher the frequency, & the higher the pitch |
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decibel (dB) |
a logarithmic scale applicable to any parameter |
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Pa (Pascals) |
the amplitude of pressure is measured in ____. |
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20 micro Pa (2x10^-5) to 20 Pa |
Range of acoustic pressures |
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0-140dB |
Manageable logarithmic scale |
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85 dB |
Government research suggests the safe exposure limit is ___ for 8 hours a day |
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Sound intensity |
the rate of sound energy transmitted in a specified direction per unit area normal to the direction |
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0.00002 Pa |
0 dB is equivalent to sound pressure level (Lp) of ____ |
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Sound Power |
the sound energy transferred per second from the noise source to the air |
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0.1 µW or 0.0000001 Watts |
An average whisper generates a sound power of _____. |
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Sound power level,Lw |
Often indicated in the machinery to indicate the total sound energy radiated per second |
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loudness |
the human impression of the strength of a sound |
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Masking |
the process by which the audibility of one sound is reduced due to the presence of another at a close frequency |
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reverberation |
the prolongation of the sound in the room caused by continued multiple reflections |
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Reverberation time |
time taken for sound energy to decay in a room by a factor of 1-million (by 60 dB ) |
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true |
True/ False: domes & concave surfaces cause reflections to be focused rather than dispersed which can cause annoying sound reflections |
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phon |
unit of loudness level |
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flutter |
rapid succession of echoes caused by the reflection of sound waves back & forth between two parallel surfaces |
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Noise Reduction Coefficient (NRC) |
A single-number index for rating how absorptive a particular material is |
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STC ( Sound Transmission class ) |
a single-number rating of a Material's or assembly's barrier effect |
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sound insulation |
required to eliminate the sound path from a source to a receiver |
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sound absorption |
Occurs when some/all of the incident sound energy is either converted into heat/ passes through the absorber |
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diffusion |
scattering or random redistribution of a sound wave from a surface |
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diffusion |
Which is extremely important for rooms used for musical performances : a) Reflection b) diffusion c) diffraction |
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diffraction |
bending/ flowing of a sound wave around an object or through an opening |
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Concave Reflector |
focus sound, causing hot spots & echoes in the audience seating area |
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Flat Reflector |
flat-hard surfaced building elements (large enough & oriented properly) that is tilted slightly; effectively distribute reflected sound. |
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large convex, hard-surfaced building elements |
most effective sound-distributing forms |
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Convex Reflector |
more evenly distributed reflected sound across a wide range of frequencies; most effective sound-distributing forms; reflected sound energy from this surface diverges, enhances diffusion , desirable for music. |