Applied Research Consortium

August 18, 2020

Heavenly Rooms: Design and fabrication of a sound absorptive panel for improving open office acoustics


Acoustic quality has a significant effect on the general satisfaction of the building occupants. Acoustics is the only category in which a LEED-rated office building performs worse than a conventional office building. The exposed hard surfaces and the lack of partitions cause easy propagation of conversational sounds between workstations in an open office. Research has shown that excess speech levels in the office can cause disturbance to the occupants and can affect their work performance. Sound absorbers are relied on for removing excess sound energy from the space. But to address the absorption of speech sounds, porous absorbers are not efficient, since their performance is limited to mid– high frequencies. Though speech sounds are broadband, most of the speech loudness is concentrated in the low frequencies. Resonant absorbers, in particular Helmholtz resonators, are effective at low frequencies and can be applied to tackle the frequencies important for speech intelligibility in open offices. This research focuses on designing a sound absorptive panel made of Helmholtz resonators of varying sizes that is effectual over a wide frequency spectrum. The optimal use of these panels and their location that can maximize the absorption of conversational sounds propagating in open offices is also discussed.

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Open office case study to analyze the improvements in acoustics with HR panels: (a) existing conditions with 64% of the area covered with acoustic ceiling tiles; (b) with just 36% of the area covered with HR panels, better acoustical conditions can be achieved.
Vidhya Rajendran

The objective of this research is to design and fabricate a sound absorptive panel composed of Helmholtz resonators of varying sizes, to improve open office acoustics.
Kim, Yang-Hann. Sound propagation: an impedance based approach. 2010

Panel samples fabricated for experimental testing: (a) Mid frequency sample 1; (b) Interior view of sample 1; (c) Low frequency sample 2; (d) Interior view of sample 2 showing the neck extensions into the cavity.
Vidhya Rajendran

Delle Macchie, Sara, Simone Secchi, and Gianfranco Cellai. Acoustic Issues in Open Plan Offices: A Typological Analysis. 2018
Delle Macchie, Sara, Simone Secchi, and Gianfranco Cellai. Acoustic Issues in Open Plan Offices: A Typological Analysis. 2018