Room Acoustics Flashcards
Describes how sounds behave
in an enclosed space.
room aocustics
The following simplification of acoustical
principles will enable you to evaluate
how much acoustical material is
required.
simplified acoustics
The loudness of direct sound waves to a
listener determined by :
The loudness of the original source and
The listener distance from the source.
When a sound wave strikes a surface
such as a floor, wall, or ceiling, the
direction of travel changed by
reflection.
reflected sound
Sound travels about ___miles per hour in all
directions.
768 miles
The
multiple reflection of sound waves has two
effects on acoustics:
(1) loudness is
increased, and (2) it causes reverberation
The loudness of reflected sound is always
less than direct sound because
(1)
reflected sound travels further & loudness
diminishes with distance, and (2)
reflected sound loses some energy by
absorption at each reflection
Loudness of REFLECTED SOUND depends in
________ while DIRECT SOUND
depends only on the ______
room absorption, distance of the source
The overall effect on loudness is
determined by:
absorption present within
the room
Reflected waves will continue
ricocheting between room surfaces
losing only a fraction of power by
absorption at each reflection.
reverberation
The
prolongation of sound is called __
reverberation
is the time measured
in seconds that a sound average
loudness can be heard before it
becomes completely inaudible under
quiet conditions
reverberation time
The time may vary from
__ second in a very “dead” room
1/2
The time may vary from __ seconds in an excessively “live”
reverberant room.
5-10
The maximum reverberation time for clear speech is about __ seconds
2 seconds
When reverberation time exceeds 2 seconds and
moves ___, speech becomes increasingly more difficult to understand.
upward
Speech finally becomes unintelligible at
reverberation times of __ seconds
4-10 seconds
Speech intelligibility improves as
reverberation time decreases below __
seconds.
2 seconds
The ideal time for classrooms or
lecture spaces is actually lower than __
1 second
Optimum reverberation time for
orchestral, choral and church music
generally ranges between ___
1.5-2 seconds
optimum reverberation time for large organs: __
2 seconds or more
optimum reverberation time for chamber music is __
1-1.5 seconds
A distinct repetition of direct sound is an?
echo
An echo is easily
distinguished if the interval is greater than
__ second in a room with low reverberation time
1/2 second
Hard, reflective, nonporous interior building
surfaces such as glass, wood, plaster, brick
and concrete absorb ___ of the
sounds, striking the surface to reflect __ or
more of the sound.
2-5%, 95%
are expressed as a percentage of the
sound absorbed.
absorption coefficient
Absorption coefficients are usually
measured at (8) cycles (Hz)
63, 125, 250, 500, 1000, 2000, 4000 & 8000 cycles
is a unit of sound absorption
equivalent to one square foot having a
coefficient of absorption of 1.00.
sabin
