Optimizing Acoustics for Effective Sound Design and Performance

High NRC-rated ceiling panels provide high-performance sound-absorption solutions—maximizing building function, occupant well-being, and compliance with building standards
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Sponsored by ROCKFON
By Robyn M. Feller

How to use the matrix: Simply rate the user’s sensitivity to noise as low, medium, or high, and then rate the potential for noise in adjacent room(s) as low, medium, or high. The matrix will give you the appropriate blocking level. Some adjacencies next to very loud things (ex: mechanical room, toilet room, band rooms, etc.) may require even higher STC ratings than shown in this matrix. Here are a couple of examples of the information this matrix could provide:

Example 1: Two regular patient rooms next to each other in a hospital setting

  • Medium potential for noise and high sensitivity to noise because deep sleep is essential to the recovery process
  • Blocking capacity should be STC 50

Example 2: A private office

  • Medium sensitivity to noise coming from other offices and a medium potential for noise in adjacent rooms.
  • The matrix tells us the STC should be 45

Note: The exact parameters don’t apply to every situation. In this private office example, for instance, it’s important to remember that not every office is the same.


Photo of a conference room.

To achieve optimized acoustic design, choose a ceiling system to optimize absorption (NRC), and where needed, use walls or plenum barriers to effectively block sound (STC).

You now know how an optimized acoustic design approach helps to achieve a true sound experience. This can be achieved by not compromising on quietness or privacy. You optimize the absorption for your specific application with a good NRC of 0.70, a better category being NRC of 0.80, or best NRC of 0.90. In addition, utilizing full-height walls or plenum barriers to achieve a good STC blocking rating of 40, a better STC rating of 45, or best blocking rating of STC 50.

This design approach will:

  • Improve speech intelligibility
  • Increase concentration and productivity
  • Increase satisfaction and recovery
  • Provide expected sound privacy
  • Meet industry standards and guidelines

The bottom line to consider when looking to adhere to the widespread implementation of more stringent codes, standards, guidelines, and rating systems for acoustic design and to really optimize the acoustic systems for your projects’ occupants is twofold: 1) ceilings are great at sound absorption; utilize it, don’t sacrifice it; and 2) walls are much better at blocking sound than modular, acoustic ceilings.

The idea is simple. Select a ceiling system to optimize absorption (NRC), and, where needed, use walls or plenum barriers to effectively block sound (STC). This approach results in acoustic designs that comply with the standards and are optimized to achieve the best sound experience at the best price—moving the industry closer to raising satisfaction and increasing health and well-being for building occupants.

End Notes

1 Summary of growing evidence of the impact of hazardous environments on human health. World Health Organization, Regional Office for Europe. www.euro.who.int/en/what-we-do/health-topics/environment-and-health/noise.

2 Health, Wellbeing and Productivity in Offices: The Next Chapter for Green Building.” World Green Building Council. 2014. http://www.worldgbc.org/activities/health-wellbeing-productivity-offices/.

3 Brill, Michael et al. Disproving Widespread Myths About Workplace Design. BOSTI Associates. 2001.

4 Frontczak, M. et al. “Quantitative relationships between occupant satisfaction and satisfaction aspects of indoor environmental quality and building design.” Indoor Air Journal. The Center for the Built Environment UC Berkeley. 2012. http://senate.ucsf.edu/2013-2014/mb1-eScholarship%20UC%20item%201wc7t219%20work%20environment%20article.pdf.

5 Madaras, G. and Heuer, A. “Effects of Noise Flanking Paths on Ceiling Attenuation Class (CAC) Ratings of Ceiling Systems and Inter-Room Speech Privacy.” http://awc.caa-aca.ca/index.php/AWC/AWC15/paper/view/129/86.

6 Madaras, G. and Heuer, A. “Optimizing Ceiling Systems and Lightweight Plenum Barriers to Achieve Ceiling Attenuation Class (CAC) Ratings of 40, 45, and 50.” Canadian Acoustics. Vol. 44 No. 3 (2016). http://jcaa.caa-aca.ca/index.php/jcaa/issue/viewIssue/272/AWC16>.

Robyn M. Feller is a freelance writer and editor specializing in the architecture, design, and construction industry. www.linkedin.com/in/robynfeller


The ROCKFON® complete ceiling system offering combines ROCKFON stone wool and specialty metal ceiling panels with Chicago Metallic suspension systems. The ROCKFON business’s approach to Optimized Acoustics is easy and results in a true sound experience for building occupants. Meet both absorption and blocking performance criteria while enjoying the style of a smooth-finished ceiling system all without breaking the budget. Hear the ROCKFON® difference at OptimizedAcoustics.com.


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Originally published in Architectural Record