Imparting physical meaning to the impulsiveness metric

The impulsiveness metric has generated interest in the building acoustics community for its ability to represent perception of transient sounds and to distinguish acoustic performance between construction designs. The metric is built on psychoacoustic formulations and outperforms sound pressure level-based metrics because of its sensitivity to perceptually important transient onset and insensitivity to the perceptually unimportant decay that follows onset. This paper scales the impulsiveness metric to reference it to a physical event, namely, a steel ball drop onto an infinite concrete slab, whose radiated sound pressure has an analytical solution. The scaled metric has a specified value, expressed in impulsiveness units (Iu), for the reference ball drop event. Like decibel scales that associate vehicle pass-by, aircraft flyover, and other events to decibel values, it is envisioned that the physical event referencing of the impulsiveness metric will increase its appeal to users.