Acoustics, as a term, is commonly used in describing the sound transmission qualities of buildings. However, when it comes to science, it goes beyond that.
Acoustics defined
In the broad sense, we can define acoustics as the science of sound. But when it is used in its conventional form to explain the properties of a building, it describes sounds reverberation or the extent to which sounds can be dampened to limit reverberation. Acoustics, in this element, can be called Architectural Acoustics.
There are many branches of acoustical engineering, and architectural acoustics is one of them. Sometimes referred to as building acoustics or room acoustics, architectural acoustics is the science and engineering involved in getting a good sound within a building. Wallace Sabine took the first step towards applied architectural acoustics. He tested the modern scientific methods of architectural acoustics in the Fogg Museum lecture room. He later applied the same principles to the design of Symphony Hall, Boston.
There are different ways to describe architectural acoustics. For instance, it can be leveraged to improve music quality in a recording studio or concert hall. It comes handy in improving speech production and reception in places like the railway station, a restaurant, or a theatre. Another common application of architectural acoustics is in improving workplaces and homes by reducing the noise that makes it into the interior.
Acoustic consultants handle architectural acoustic design.
Typical Acoustic Applications in Architecture.
In hospitals
No patient can recover in an environment where a sound sleep is impossible. A doctor will struggle to communicate effectively with a nurse in a chaotic environment littered with beeping sounds from heart rate monitors, continuous chattering by patients, and squeaks from carts moving around. A hospital environment with so much distraction leaves room for errors.
Yes, most hospitals have regulations in place to forestall such costly mistakes. But the most effective way to deal with unwanted ambient noise is by adopting acoustic treatment. In hospitals where there are hard floors and ceilings, sound reflection tends to increase noise levels in an already chaotic environment. However, replacing hard tiles with sound-absorbing ones may just fix this problem.
Sound absorbing ceiling tiles have shown to improve sleep and contribute to improved nursing care. This, in turn, reduces the stress levels of the medical staff.
In schools
For students, it is difficult to pay attention in a class where the lecturer is barely audible. Teachers, on the other hand, are always struggling to keep up a volume higher than the students’ and ambient noise. This is even more difficult in lecture rooms with poor acoustics. Below-par acoustics increases reverberations and amplifies the slightest noise. An increased noise floor translates to increase frequency.
All of these problems make it difficult for students to learn as expected. Severe cases may lead to a considerable loss in intelligibility and concentration. These can be resolved by installing acoustic absorbers in the classroom to heighten speech intelligibility and improve reverberation time. Overall, the quality of education increases with better architectural acoustics in the classroom.
Health and Well-being
Higher noise levels can adversely affect cardiovascular health, leading to severe conditions like increased heart rates and higher stress levels. However, when acoustic considerations are made while designing the architecture, it helps to manage sound transmission across living spaces better. This, in turn, improves our productivity and our quality of life.
Moving forward, let’s take a look at the science behind most acoustic applications in architecture.
The Science Behind Architectural Acoustics.
Building Skin Envelope
One way of applying architectural acoustics is by building a skin envelope. It involves analyzing noise transmission from the exterior envelope of a building to the interior, and vice-versa. This noise passes through the roofs, windows, walls, eaves, doors, and other penetrations. Improved space functionality is achieved by ensuring adequate control measures. These measures must be in line with the building use laws and local municipal codes. For instance, a home situated close to a railway station or a busy airport will need a building skin envelope.
Interspace Noise Control
Improved space functionality is not the only perk of adequate noise transmission across building spaces – it also ensures speech privacy. In this case, the sound passes through the acoustic ceiling panels – wood dropped ceiling panels, room partitions, ceilings, windows, ducting, doors, and other penetrations. Where the noise is coming from, and acoustic transmission paths are considered when developing suitable technical solutions. Inter-space noise control is applied by creating adequate party wall design for use in an apartment complex. This considerably limits the mutual disturbance caused by noise from people in adjacent apartments.
Interior Space Acoustics
The introduction of diffusers has shown to improve the acoustics of a room. These diffusers are designed to disperse sound. The science involves regulating the surfaces of a room in line with its ability to reflect and absorb sound. Poor speech intelligibility is often caused by excessive reverberation time. Standing waves resulting from sound reflections create natural resonances, which come off the human ear as either disturbing or pleasant. Targeted coordination and angling of reflective surfaces can deliver excellent sound coverage for a listener in spaces like a concert hall or music recital room. Here is a practical illustration of this technique – the difference in a conventional classroom with the hard surfaces and a modern lecture theatre, or better still, a large office meeting room.
Interior building surfaces can be made from various finishes and materials. However, in a proper acoustic panel, the choice face or finish material must suit the acoustical substrate or infill. The use of heightened fabric-covered panels ensures maximum acoustical absorption, the same with perforated metal. The finish material is used as a cover over the acoustical substrate. Popular acoustical substrates include Micore, also referred to as the mineral fiberboard. Most finish materials comprise acoustical tile, wood, or fabric. It is possible to achieve a “pre-fabricated panel” by wrapping the fabric around the substrates. This further heightens their noise absorption when eventually installed on the wall.
Here is a three-way approach to solve most workplace sound problems or acoustics – it is called the ABC’s, where:
- A indicates Absorption through the ceiling tiles, carpets, drapes, and other penetrations;
- B indicates Blocking through panels, floors, walls, ceilings, and layout.
- C indicates Covering Up through sound masking.
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Article by HL Architects in Durham North East UK