THE SCIENCE AND APPLICATIONS OF ACOUSTICS - H. H. Arnold ...

11.15 Concert Halls and Opera Houses 269ceilings, walls, and floors from both airborne and mechanical vibrations. Thedouble-wall construction generally consists of 6-in. solid high-density blocks separatedby a 2-in. air gap. The huge windows in the Grand Foyer facing the riverconsist of 1.27-cm (1/2-in.) and 0.64-cm (1/4-in.) thick glass sheets separated bya 10-cm (4-in.) air gap. Resilient mounts are used to isolate interior noise sources(e.g. transformers, air-conditioning units, etc.) The ductworks are acousticallylined, flexible connectors are used, special doors are installed at all auditoriumentrances together with “sound locks” between foyer and the auditoriums.The rectangular concert hall encompasses a volume of 682,000 ft 3 and accommodatesan audience of 2759. Large contoured wall surfaces and a coffered ceilingabet the diffusion of sound at low and high frequencies. The 11 massive crystalchandeliers, each weighing 1.3 metric ton, donated by the Norwegian government,also contribute to the diffusion. The balconies are purposely shallow to preventreduction of sound below the balcony overhang. Unoccupied, the concert hall hasa reverberation time of 2.2 s at 500 Hz and 2.0 s at 1 kHz; the corresponding valuesare 2.0 s and 1.8 s for the fully occupied hall.Located in downtown Seattle, Washington, Benaroya Hall opened in September1998, contains two spaces for musical performances: a 2500-seat main auditorium(Figure 11.15) and a more intimate 540-seat recital hall. The main auditorium, theS. Mark Taper Foundation Auditorium, is a classic rectangular configuration withthe stage enclosed in a permanent acoustic shell. LMN (Loschky, Marquartdt andFigure 11.15. Seattle Symphony performing in Benaroya Hall in Seattle, WA under thedirection of Music Director Gerard Schwarz. (Courtesy of the Seattle Symphony, photographby Craig Raymond.)