Controlled minimum background sound, the missing link in acoustic design

Abstract

Current industry standards related to controlling background sound in occupied spaces are all based on “not to exceed” maximum levels. At the other end of the scale, it is assumed that we cannot predict with any degree of certainty how low the background sound level may descend, what its spectral composition is, and when or how it may vary. Given that the “signal to noise ratio” is fundamental to all communication based acoustic design, the absence of this knowledge presents significant challenges. As a consequence, we adapt our acoustic designs to compensate for our inability to control minimum noise levels by over-specifying STC, CAC, and NRC values in order to obtain the desired results. And yet, precise generation of controlled minimum background sound levels is readily available. This session explores the negative impact of traditional compensatory acoustic design practises, the significant value of incorporating predictable/consistent minimum background sound levels into acoustic design planning, and makes a case for establishing minimum background sound level industry standards.