Fundamentals of Interior Acoustics: Sound Minds Require Sound Design

Interior Acoustics

You may call Interior Acoustics a blend of Science and Design, for it requires due attention to both functional optimization and aesthetics. These days, a range of devices have come to replace traditional acoustical materials in Interior Design. With new advancements in technology and wider research in the interior acoustics domain, designers have the opportunity to explore a wide array of options for revamping their spaces.

It is safe to say that a successful design is one in which the user feels comfortable within the space. From the most crowded restaurant to the quietest bedroom, acoustic comfort plays a vital role in user satisfaction; this happens when the user experiences a sense of well-being in terms of the acoustical conditions of their environment.

Focusing on Acoustic Design for Interiors helps optimize the user’s experience with respect to the functionality of the space. 

The Need for Interior Acoustics Optimization

Acoustical performance depends on reducing unwanted sounds and maintaining or improving the intelligibility of the required sounds. Research has shown that prolonged exposure to high noise levels significantly impacts productivity and performance. Unwanted noise can also lead to a general reduction in physical and psychological well-being. Heart diseases, increased stress levels, hearing impairment, sleep disturbances – these are all side effects of noise exposure.

In hospitals and rehabilitation centres, unwanted noise can slow down the recovery process of patients. It may even heighten their pain and discomfort. Everything, from the materials used to the space planning, inevitably impacts the acoustics of the space. It would thus be simply reckless for architects and designers to not place adequate emphasis on Acoustics in their projects.

The Varying Demands of Interior Acoustics

The acoustical demands of a space vary according to the purpose that it serves. One can derive specific acoustical requirements by understanding functionality and spatial interactions. For instance, let us look at some spaces and their fundamental acoustic requirements below:

Spaces and their Acoustical Considerations

  • Spaces such as Classrooms and Courtrooms, which rely on speech intelligibility, must incorporate materials that absorb and diffuse sound instead of reflecting it.
  • In Airports and Malls, where public announcements are frequent and foot traffic is high, it is pertinent to ensure audibility and intelligibility while avoiding auditory discomfort. 
  • In places like Restaurants and Bars, which are busy with people talking over each other and often have music playing too, it is better to use materials that absorb sound and minimize reverberation.
  • Auditoriums and Theatres need to maintain an even distribution of sound without any echoes. The M-Auditorium in Mumbai, designed by Planet 3 Studios, is a 300-seat auditorium. Featuring wood-faced acoustical boards on the walls and ceiling, the acoustical design of the auditorium diffuses sound from the stage to the back rows without compromising the intensity, while keeping the reverberation to a minimum.
M-Auditorium Interior Acoustics
M-Auditorium by Planet 3 Studios, Mumbai (Image: Arch Daily)
  • Medical Clinics and Residential Spaces require higher levels of privacy and, as such, require higher levels of sound absorption.
  • Similarly, Museums and Libraries are highly dependent on quietness and calmness to function optimally. In such spaces, the materials chosen must be capable of absorbing sound and reducing diffusion. 

Modern trends in design tend to prefer open-plan spaces. These days, it is quite common for offices to have free-flowing circulation patterns with separate conference halls and meeting rooms. Thus, the requirements vary depending on the space’s purpose, and the acoustical solutions must cater to its demands. 

Various Sound Treatment Methods in Interior Design

Effective acoustical treatment involves controlling the levels of absorption, reflection, diffusion, and transmission using various treatment methods. 

Acoustic Panels/Sound Absorption Panels

These are vertical or horizontal panels made of sound-absorbing materials such as mineral wool or foam. These panels may be attached to walls or ceilings or simply placed vertically as free-standing panels.

They absorb the sound waves directed towards them and effectively reduce reverberation and noise in small rooms. Studio 3, located in Delhi, has a conference area that is part of the studio workspace. The manually operable partition lined with acoustic treatment panels is moveable, and demarcates an acoustically sound conference room. 

Studio 3 Interior Acoustics
Studio 3 by Architecture Discipline (Image: Arch Daily)

Bass Traps

Bass Traps are a common feature in recording studios or home theatres. Low-frequency sounds tend to cause significant acoustic disruption and dampen the quality of the sound.

Bass traps reduce low-end frequencies by absorbing o converting the kinetic energy of sound waves into thermal energy through friction. Usually placed at the corners of the rooms, bass traps reduce reverberation to improve the overall sound quality. 

Skyline Diffusers

A sound diffuser allows the repeated redirection of sound waves rather than reflection or absorption. It allows for the hearing of sound clearly in a large room without any echoes.

One can make Skyline Diffusers out of Wooden Columns of varying lengths mounted on the wall. Their name roots in their resemblance to a city’s skyline from the side. The variation in the length of the wooden columns allows for the diffusion of varying frequencies of sound. 

Ceiling Clouds

These are ceiling panels in varying designs meant to absorb, reflect, or diffuse sound, typically in large open spaces. There is a lot of room for customization with these panels. Besides, they have recently become a major architectural trend due to their visual appeal. The height, depth, and the number of ceiling clouds depend on the acoustic requirements of the area.

Acoustic Baffles

Acoustic Baffles are usually suspended vertically from ceilings and work similarly to wall-attached acoustic panels. Baffles reduce sound reflections and echoes and find application in large open areas with high ceilings. A recently renovated office in Pune has partition walls made of cardboard and medium-density fibreboard.

Not only is cardboard recyclable, but it also has excellent sound-absorbing properties. Thus, the partition walls act as baffles and maintain privacy within the office. 

Studio VDGA interior acoustics
Studio VDGA in Pune has made Partition Walls out of Cardboard and MDF (Image: Dezeen)

Active Methods of Interior Acoustics Treatment

So far, the methods of acoustic treatments discussed relied on the architecture of the space. The usage of sound treatment elements such as absorbers and diffusers was the prime solution. Hence, we call them passive sound treatments.

On the other hand, active acoustic treatment methods use a system of microphones, loudspeakers, and electronic processors. These help detect sounds and appropriately reflect them. There is optimum room for modification to suit the acoustic requirements of the space.

Active sound treatment allows for more freedom within the architecture and even increases the possibilities of multi-functional spaces. Therefore, they are especially useful in auditoriums and theatres.

Interior Acoustics: Integral Aspect of Designing

An acoustically well-designed space isolates unwanted external noise, cuts down reverberation, and appropriately conducts required sounds. In other words, it is one in which the user can carry out their activities unhindered by acoustic interferences. Often, when we think of comfort within a space, we tend to think only in terms of temperature and lighting. Being aware of the characteristics of the importance of Acoustics in Architecture helps us decide the right materials and design. This inevitably leads to better choices for improving user experiences.

Nandini Avadhanam
Nandini Avadhanam

Nandini Avadhanam is a 3rd-year architecture student at Manipal School of Architecture and Planning. She believes in the power of authenticity and integrity in writing, architecture, and in writing about architecture. She is also an avid reader, a dancer, and is passionate about a holistic, community-centric approach to designing spaces.



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