As acoustical consultants, we incorporate a wide variety of finishes to the walls, floors, and ceiling of a space to meet the design criteria. But what about glazing? Windows, skylights, glass partitions and doors and decorative glazing are all part of the aesthetic and functional design of a space. And in almost all cases, glazing causes tricky acoustical issues. In general, glazing creates two types of acoustical problems: it does not attenuate sound very well, so noise may leak in; and it reflects sound in the speech frequencies very well, causing disruptive echoes. Yet the light and visibility that glazing provides are not something you want to just cover up for the sake of better acoustics – you don’t want good sound at the expense of natural light, or vice versa.
-Clearsorber, a transparent micro-perforated product, can be mounted in front of a window pane and provides an effective absorptive surface without blocking either the light or the view. The product comes in a Sheet, Foil, or Panel form, and each form has a variety of thicknesses. The airspace between the Clearsorber product and the window can be modified to provide the optimum level of absorption based on the use of the space.
We recently had the opportunity to specify this product for a worship space: the new Christ Community Church of Milpitas Social Hall in San Francisco’s East Bay. The Hall will be used for a variety of instrumental and vocal performances. Its layout includes a 530-square foot, elevated stage that faces a 38-foot span of glazing, split into 3.5-foot by 9-foot frames that are angled to form a convex curve. This presented a special challenge because in addition to the above-mentioned acoustical problems of glazing, the convex curved surface focuses sound into “hot spots” that disrupt an even sound field and are even worse than echoes. We recommended the Clearsorber Sheet in this project to maintain the natural lighting and exterior views that the glazing provides. The resulting absorption is roughly comparable to that of a medium-density fabric window treatment – while retaining the light!
Every day, it seems new tools are being developed to make it simpler to balance aesthetics with acoustical function, paving the way for more unique designs. And, in the case of the Christ Community Church of Milpitas, we have another successful TA project!