AES Section Meeting Reports

Pacific Northwest - October 29, 2019

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The AES PNW Section held its October meeting in the South Lake Union offices of Stantec, to hear acoustician Katie Gray speak about architectural acoustics. Katie gave an overview of architectural acoustics, what kinds of things she does, how projects are conceived and managed, some case studies and a demonstration of office noise masking. About 30 people attended (17 AES members).

Stantec is a large, global architecture and engineering design firm with some 22k employees, and Katie is one of about 10 people specializing in architectural acoustics. She has worked on a variety of projects, including recording studios, theaters, schools, hospitals, and commercial offices. She holds a M.A. in Acoustics from the Peabody Institute of the Johns Hopkins University, and a B.M. in Violin Performance from Towson University.

She first gave an overview of architectural acoustics and its importance in building design. Typically, they work on room acoustics, acoustic isolation, environmental noise (such as flight paths), and noise & vibration control (such as HVAC). Many factors count in common rooms, such as interior treatments, wall, ceiling and floor construction. A ray tracing animation was shown. Isolation/separation of sound can be tricky — sounds can travel in sneaky paths through buildings. Site noise studies may be done to find environmental noise; a simple Google map can often help. Noise and vibration control can involve examining sources such as fans, chillers, transformers and motors, and determining how to isolate them.

Next came a description of how projects are managed, from predesign to schematic design, where acoustical consultants are typically brought in, and design development, where the specs are drawn up. In the construction phase, bids are made and construction is administered. Public projects must take the lowest bidder, which often leads to problems. Many project clients have little thoughts about acoustics and need to be educated. An acoustician must work carefully with the other project engineers to ensure their specs are carried out.

Some case studies were shown. The first was a hospital design, with considerations for modular walls, medical equipment, and infection control as well as acoustical design.

Another case study was a vintage theater redesign. Many general criteria for auditoria were discussed.

At this time, a break for cookies and prizes was held. Winners were:
-Set of AES coasters, via Bob Moses, won by Rene Jaeger
-Neutrik/Shure branded phone stand/bottle opener, via Rene Jaeger, won by Wayne Edwards
-Fluke Networks bags (empty), via Rick Rodriguez, won by Rob Baum and Tom Hall
-Set of AES 2019 NYC Convention Dailies, via Gary Louie, won by Tim Langlois

After the break, Steve Turnidge spoke for a few minutes about Audio Test Kitchen, then Dan Mortensen talked about the AES 147th Convention in New York.

Katie finished with design considerations for commercial offices. Open plans without private offices or cubicles are popular, which have noise and "hearing your neighbors talk" problems. Mostly what an acoustician has left to work with is ceiling absorption and noise masking. Natural noise (HVAC) is hard to control, so electronic noise masking is popular. Two groups were taken to her Stantec demo office area with electronic noise masking.

Some suggested reading on architectural acoustics included Marshall Long's Architectural Acoustics, anything by Leo Beranek, and several texts on the acoustics of small rooms.

An extensive Q&A session covered many topics, from the physiological effects of masking noise, diffraction shapes, the non-absorptive nature of wood, the Golden Ratio, a new type of sound isolating stud construction, and acoustic fabrics.

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