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Acoustics of Concert Halls and Rooms
SOME BASICS OF ARCHITECTURAL ACOUSTICS
Auditorium Acoustics
Science of Sound, Chapter 23
Principles of Vibration and Sound, Chapter 11
Kimmel Center
Free field
Reflections
p vs r log p vs log r
SOUND FIELD
Sound decay
Sound decay in a400 m3 classroom
Sound pressure level as a function of time for that room
GROWTH AND DECAY OF REVERBERANT SOUND
RT = K (volume / area)RT = 0.161 V/A (V in m3; A in m2 )If room dimensions are given in feet, the formula may be written:
RT= 0.049 V/A (V in ft.3 ; A in ft.2 )
Decay of reverberant sound
(a) and (b) are decay curves of sound pressure and soundlevel in a room with uniform energy distribution(c) shows different initial and final reverberation times(d) shows peaks due to prominent standing waves or roomresonances
CALCULATING REVERBERATION TIME
CALCULATING REVERBERATION TIME
Desirable reverberation times
for various sizes and functions
Variation of reverberation time with frequency in
good halls
McDermottConcert
Hall(Dallas)
Orchestra Hall
(Chicago)
MeyerhofSymphony
Hall(Baltimore)
Walt Disney Concert Hall
Disney
KimmelCenterAuditorium
BACKGROUND NOISE CRITERIA
• Spatial impression• Intimacy• Early decay time• Clarity• “Warmth”
Important criteria for concert halls:
Concerthalls
throughoutthe
World