03 May Basic Principles of Acoustics: Why Architects Shouldn’t Leave It All To Consultants
Basic Principles of Acoustics: Why Architects Shouldn’t Leave It All To Consultants
More than half the world’s population lives in dense urban areas. Uncomfortably loud restaurants, stores, hotels, or offices are enough to keep patrons away. When planning a meeting or even a night out with friends, we are conscious of selecting a location where we can focus and hear one another. The noisier our world gets, the more difficulty we have focusing on the sounds we actually want to hear.
Since the beginning of time, our ears have warned us of approaching danger. While their function remains the same, the dangers of today are different than they were in the past. Unwanted sounds can have serious health effects such as: hearing loss, cardiovascular disease high blood pressure, headaches, hormonal changes, psychosomatic illnesses, sleep disorders, reduction in physical and mental performance, stress reactions, aggression, constant feelings of displeasure and reduction in general well-being. With this laundry list of side effects, it would be foolish to leave the acoustic comfort of our spaces up to consultants alone. When we take acoustic comfort into our own hands, the end result can be quite extraordinary.
How Acoustic Comfort Works
Even during sleep, our outer, middle, and inner ear, receive, transmit, and detect sound respectively. Sound pressures cause the eardrum to vibrate, stimulating nerves in the inner ear. Differences in pressure determine volume, measured in decibels. Vibration cycles per second determines the pitch, or frequency, measured in Hertz.
Indoor acoustic quality is dependent on how well sound sources are controlled. Exterior, interior, impact, and equipment noises are transmitted through the air or building fabric. How the human ear perceives sound directly depends on levels of reverberation and absorption within the building. To assess a buildings acoustic comfort, sound level and room acoustics are evaluated. Sound level is measured by background versus peak noise levels. Room acoustics are measured by reverberation time, intelligibility level, and privacy level. Depending on the functionality of the building or room, different acoustic requirements will apply.
How To Design For Acoustic Comfort
To design for acoustic comfort, consider occupant needs along with external and architectural factors: the building program, cultural habits, noise types, noise spectrum, construction systems and materials. Sound is challenging to accurately predict. Forecast external noise levels through site analysis and a narrative explaining the building’s performance requirements, building fabric, and technical equipment needs. True on-site analysis cannot be replaced by computer simulations, which don’t have human ears. Ultimately, acoustic performance comes down to workmanship.
Where Should Architects Get Involved?
Once the programmatic needs are known (and the correct noise levels are already determined with the help of a specialist) it’s time for materials to be selected. This is exactly where architects should be more involved and where they can make a difference in the design and expression of the building (inside and out).There is a wide variety of customizable materials available such as acoustic wall and ceiling panels which area a great way to reduce sound reflections. Also acoustic glass integrates a film interlayer to diminish sound transmission without sacrificing transparency, and this can be a great way to create interior sub-divisions in modern cowering spaces, for example. And we should never forget the correct use and application of noise-proofing sealant which prevents unwanted noise from escaping a room through minimum gaps and cracks. Finally, an on-site testing ensures the specified performance is achieved.
Acoustics are a key element in all building types from hospitals, educational buildings, sports centers to residential or working and music venues. Each typology in architecture will have it’s own acoustic requirement and that’s why architects cannot design a comfortable and sustainable building without the previous research and knowledge. To achieve a perfect acoustical space we must be aware of the technologically-advanced materials which maintain world-class acoustics. As our cities densify, neighbors grow closer, people work from home, and building types become more and more mixed use, the indoor acoustic landscapes is evolving. Climate change has already raised noise levels by increasing our use of air conditioning systems. Storms are intensifying, bringing about more vibrations. Our buildings will require better insulation to protect occupants from internal as well as external noise. At the end of the day, the way we “hear” in a space not only affects our appreciation of it, but our productivity, our capacity of learning, our sleep, comfort and general wellbeing, as well.
Originally published on November 2, 2019. Updated May 28, 2021.