Uncertainty in room acoustics: A consultant's perspective

Abstract

Faced with time and budget constraints on most projects, acoustical consultants make a series of choices when asked to evaluate the acoustics of an existing space. Measure the impulse response of the room with sophisticated technology (MLS, sine-sweeps, etc.), or pop a balloon? Use a dodecahedral loudspeaker (or several), a more standard portable amplified loudspeaker, or the house sound system (or pop a balloon)? Use a single omni-directional microphone, a binaural dummy head, or a B-format soundfield microphone? How many source locations, and how many receiver locations? Whither measure? There is a growing body of literature that identifies uncertainty and inconsistency in reverberation time and other room acoustics metrics and the tools used to obtain them. The authors will add modestly to this evidence from consulting experience, and then focus on how some consultants in architectural acoustics choose what data to gather, how to gather it, and to what extent. Considerations of time, budget, and logistics factor in those choices, as do determinations regarding the essence of the client's needs and concerns, subjective listening to determine what measurements could be most useful, and our own expectations for how we might use the measurements we make, now and in the future.