Acoustical design and uncertainty: Can we beat the MacLeamy curve

The MacLeamy curve is a useful framework for identifying design milestones and counteracting the cost of uncertainty. If uncertainty is inherent in aspects of design, then the MacLeamy curve suggests that risk can be minimized by identifying these uncertainties early on in the project. Even if the details are not fully formed, a contingency budget can be established until more accurate costs are known. Despite best efforts, there are moments in construction where situations become uncertain. This presentation will discuss several acoustical recommendations in the context of the MacLeamy curve and how designers can embrace the uncertainty. The discussion will be framed around a recently completed project in northern Minnesota. Its remote location made quantifying site noise a challenge; however, its proximity to a freight train required close understanding of the environmental noise impact. Additionally, the project had a number of sound isolation assemblies where no data exists: precast enclosure, double pane exterior windows, and a sliding barn door. Finally, the project auditorium had several variable elements: retractable seating, acoustic curtains, and separate theatrical curtains. The presentation will discuss how the room acoustics were modeled for these various configurations. Uncertainty is unavoidable, but there are ways to minimize its impact.