Notes
1 Refer to the study, “Hearing Architecture: Exploring and designing the aural environment,” Journal of Architectural Education.
2 The decibel (dB) is typically used to express the “loudness” of sound. The scale is logarithmic, so although the numerical difference between two levels might appear small, the actual difference is exponential. For example, the energy of an 80 dB sound is 1,585 times greater than one of 48 dB. Expressed in terms of distance, if 80 dB is equivalent to 1.6 km (1 mile), 48 dB is only 1 m (3.3 ft).
3 The A-weighted level (dBA) provides better indication of occupants’ impression of sounds than the decibel (dB) because it applies a set of “corrections” to instrument-measured sound levels that account for our sensitivity to different frequencies. For example, if two tones such as 200 Hz and 1,000 Hz differ in non-weighted level—60.85 dB and 50 dB, respectively—one may still perceive them as having equal “loudness” (e.g. 50 dBA) because people are less sensitive to lower-frequency sounds than higher ones.
4 Refer to the study, B. Brown, P. Rutherford, and P. Crawford, “The role of noise in clinical environments with particular reference to mental health care: A narrative review,” International Journal of Nursing Studies, vol. 52, no. 9.
5 See the research, “Designing for Neurodiversity: Creating spaces that are inclusive of all,” at
www.stantec.com/en/ideas/topic/buildings/designing-for-neurodiversity-creating-spaces-inclusive-of-all.
6 To help prevent hearing loss related to use of a personal audio system (PAS) such as a mobile phone and headset, one should follow the recommendations outlined in ITU-T H.870 (03/2022), Guidelines for safe listening devices/systems. It is also important to note that noise-cancelling headphones block speech and background noise equally, meaning the relative difference between them remains the same; they do not reduce speech intelligibility.
7 Consult the journal by T. Parkinson, S. Schiavon, J. Kim, and G. Betti, “Common sources of occupant dissatisfaction with workspace environments in 600 office buildings,” Buildings and Cities, 4(1).
8 See note 5.
9 Information from Gensler Research Institute, “Returning to the Office” briefing based on data captured by Gensler’s U.S. Workplace Survey 2022.
10 To avoid interruption from external sources, the intentional introduction of aural experiences in spaces requires careful control of their boundaries and the acoustic conditions within them.
11 Level is a single-value metric arrived via the sum of its frequency components, measured over time. Its simplicity—in terms of both measurement and as a concept—is one reason why it is commonly used by professionals in the building industry, but there are nuances to this parameter that often cause confusion as sound is measured over time, a constant sound and an intermittent sound measured over a certain sampling period may be equal in level and the numeric value offers little insight into the characteristics of a noise, only its relative “loudness.” Sounds can also vary in spectrum (rumbly, buzzy, hissy), temporal characteristics (constant, fluctuating, surging, intermittent), as well as spatially (overhead, adjacent, throughout a space).
12 For more on this topic, see “A Reintroduction to Acoustics: Perception of sound and noise in the built environment” by V. Koukounian and N. Moeller in the July 2020 issue of Construction Canada.
13 Refer to the paper by D. Fink, “A New Definition of Noise: Noise is unwanted and/or harmful sound. Noise is the new ‘secondhand smoke,” Acoustical Society of America’s Proceedings of Meetings on Acoustics.
14 Similarly, music and nature sounds cannot be relied upon to mask noise and speech adequately or consistently. It is also important to note that they are also subject to personal preference, and occupants’ response to nature sounds (e.g. running water) can be further affected by lack of associated visual stimulus (e.g. a waterfall). Where appropriate (e.g. in lobbies and relaxation rooms), these sounds can be used in conjunction with masking; the latter establishes the foundation for speech privacy and noise control, while the former achieves other auditory goals.
15 For more on this topic, see ‘Creating Acoustical Equity: Controlling temporal, spectral, and spatial properties of sound’ by V. Koukounian and N. Moeller in the September 2022 issue of Construction Canada.
Authors
Niklas Moeller is the vice-president of K.R. Moeller Associates Ltd., manufacturer of the LogiSon Acoustic Network and MODIO Guestroom Acoustic Control. He has more than 25 years’ experience in the sound-masking industry. Moeller can be reached via email at nmoeller@logison.com.
Viken Koukounian, PhD, P.Eng., is director of engineering at Parklane. He is an active and participating member of many international standardization organizations, such as the Acoustical Society of America (ASA), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), ASTM, the Green Building Initiative (GBI), and the International WELL Building Institute (IWBI), the Standards Council of Canada (SCC), and also represents Canada at International Organization of Standardization (ISO) meetings. He completed his doctorate at Queen’s University (Kingston, Ontario, Canada) with foci in experimental and computational acoustics and vibration. Koukounian can be reached via email at viken@parklanemechanical.com.
