Concept of architectural Acostics

1. 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

2. Free field
Reflections
p vs r log p vs log r
SOUND FIELD

3. Sound decay
Sound decay in a
400 m3 classroom
Sound pressure level as a
function of time for that room

4. 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 )

5. Decay of reverberant sound
(a) and (b) are decay curves of sound pressure and sound
level in a room with uniform energy distribution
(c) shows different initial and final reverberation times
(d) shows peaks due to prominent standing waves or room
resonances

6. CALCULATING REVERBERATION TIME

7. CALCULATING REVERBERATION TIME

8. Desirable
reverberation times
for various sizes and
functions
Variation of
reverberation time
with frequency in
good halls

9. McDermott
Concert
Hall
(Dallas)

10. Orchestra
Hall
(Chicago)

11. Meyerhof
Symphony
Hall
(Baltimore)

12. Walt Disney Concert Hall

13. Disney

15. Kimmel
Center
Auditorium

16. BACKGROUND NOISE CRITERIA

17. •Spatial impression
•Intimacy
•Early decay time
•Clarity
•“Warmth”
Important criteria for
concert halls:

18. Concert
halls
throughout
the
World