Room Acoustics

DHC 161March 2, 2011

Early sound in a room

concert hall design

Boston Symphony Hall

Concertgebouw Amsterdam

Istanbul, Turkey Radio Concert Hall, Denmark

reverberationchamber

anechoicchamber

Special Rooms

Standing waves

Chladni plate patterns

Practice calculation

3.2 m

12.5 m

speed of sound is 342 m/s

horizontal modesvertical modes

fundamental

€

c2L

=342 m/s6.4 m

= 53.4 Hz

€

c2L

=342 m/s

25 m=13.7 Hz

we know that boundaries are fixed-fixedstanding waves in a room

2nd harmonic

3rd harmonic

106 Hz

159 Hz

212 Hz4th harmonic

27.4 Hz

41.1 Hz

54.8 Hz

nth harmonic n*53.4 n*13.7

These frequencies will be amplified by the room