Dana L. Kirkegaard
Kirkegaard & Associates, 4910 Main St., Downers Grove, IL 60515
In a performing arts facility, many design decisions take into account the influence that audience and performers will have in modifying the acoustics of the unoccupied or sparsely occupied hall. When correlating subjective experience to objective measures, it is very important to assess whether the phenomena being studied are dependent upon the presence of performers and/or audience, and to structure objective measurements accordingly. The impact of occupancy varies widely, and is dependent upon the location of important reflective surfaces. The musicians, music stands, and audience members can be obstacles to the direct sound and wall reflections. This impacts ensemble conditions onstage [Kirkegaard et al., ``Concert Acoustics: The Performers' Perspective,'' J. Acoust. Soc. Am. Suppl. 1 84, S20 (1988)] as well as issues of clarity, imaging, and envelopment in the audience. In some notable cases, the character of the fixed absorption---seating predominantly---changes the spectrum and spatial quality of the reverberation with occupancy. Comparisons of occupied/unoccupied data will be used to illustrate the dependence of the early echo structure and reverberation upon occupancy and its relationship to the design process.