the world's most visited architecture website
i

Sign up now and start saving and organizing your favorite architecture projects and photos

Sign up now to save and organize your favorite architecture projects

i

Find the most inspiring products for your projects in our Product Catalog.

Find the most inspiring products in our Product Catalog.

i

Get the ArchDaily Chrome Extension and be inspired with every new tab. Install here »

i

All over the world, architects are finding cool ways to re-use run-down old buildings. Click here to see the best in Refurbishment Architecture.

Want to see the coolest refurbishment projects? Click here.

i

Immerse yourself in inspiring buildings with our selection of 360 videos. Click here.

See our immersive, inspiring 360 videos. Click here.

All
Projects
Products
Events
Competitions
Navigate articles using your keyboard
  1. ArchDaily
  2. News
  3. How Acoustic Shells Work (And How to Design Them Effectively)

How Acoustic Shells Work (And How to Design Them Effectively)

  • 09:00 - 5 March, 2018
  • by
  • Translated by Guilherme Carvalho
How Acoustic Shells Work (And How to Design Them Effectively)
How Acoustic Shells Work (And How to Design Them Effectively), © Matheus Pereira
© Matheus Pereira

Acoustic shells are iconic elements seen in public spaces around the world. But beyond their curious form, their operation is highly interesting. Inspired by the design of the human ear, the sound waves produced within acoustic shells are organized by their form, becoming stronger and more vivid for the audience in front of the structure.

From a technical point of view, sound propagation is carried out by reverberations that, when created inside the shell, are directed by the concave shape towards the spectators. In other words, after a sound is made, it hits the shell and, due to the shell's carefully calculated form, is distributed to the audience. Another object that uses the same reasoning is the iconic Brazilian pay phone developed by the architect Chu Ming Silveira.

© <a href='https://www.flickr.com/photos/agenciabrasilia/22302551342'>Agência Brasília via Flickr</a> licensed under <a href='https://creativecommons.org/licenses/by/2.0/'>CC BY 2.0</a>. Image Complexo Concha Acústica de Brasília
© Agência Brasília via Flickr licensed under CC BY 2.0. Image Complexo Concha Acústica de Brasília
Acoustic Shell of Brasília / Oscar Niemeyer. Image © Gonzalo Viramonte
Acoustic Shell of Brasília / Oscar Niemeyer. Image © Gonzalo Viramonte

In the design of acoustic shells, each structure should be considered on a case-by-case basis, due to the spatial variations of each setting in which they could be used. However, they can generally be conceived as a geometric result of following a radius projected in three dimensions from a point in the audience, like a cone lying on its side. This point should therefore be about the same distance from every point of the concrete shell; however, varying geometries are possible that come close to this, and a successful acoustic shell could very well follow a folding geometry, or be created from geometries in a saddle or crest shape. Generally, they are formed by semicircular base and parabolic openings.

However, there are other factors involved in the proper functioning of acoustic shells. Usually, the ground outside the shell needs to be inclined, since this allows better visibility for the audience, and seating may also be arranged radially in an amphitheater form. Climatic conditions are also important for proper operation, since if the wind speed exceeds 15 kilometers per hour, this may cause disruption to the sound. [1] Environmental materials should also be considered, because certain natural materials, such as grass, partially absorb sound waves, while water surfaces are excellent reflectors.

Conchas Acústicas / Flanagan Lawrence. Image Cortesia de Flanagan Lawrence
Conchas Acústicas / Flanagan Lawrence. Image Cortesia de Flanagan Lawrence

Many architects, especially in the modern period, have developed iconic acoustic shells: Oscar Niemeyer, Henrique Mindlin, Décio Tozzi, among others. Nowadays, the system is applied to a lesser extent, since this model has been replaced by closed theatrical buildings, where the nuances of sound are controlled by more modern technologies. To provide inspiration, we have selected some acoustic concrete shells already published on ArchDaily:

Acoustic Shell of Brasília / Oscar Niemeyer

Acoustic Shell of Brasília / Oscar Niemeyer. Image © Gonzalo Viramonte
Acoustic Shell of Brasília / Oscar Niemeyer. Image © Gonzalo Viramonte

Rehabilitation of the Acoustic Shell of the Parque Agua Azul / S2 Arquitectura

Rehabilitation of the Acoustic Shell of the Parque Agua Azul / S2 Arquitectura. Image © Carlos Garza
Rehabilitation of the Acoustic Shell of the Parque Agua Azul / S2 Arquitectura. Image © Carlos Garza

Acoustic Shells / Flanagan Lawrence

Conchas Acústicas / Flanagan Lawrence. Image Cortesia de Flanagan Lawrence
Conchas Acústicas / Flanagan Lawrence. Image Cortesia de Flanagan Lawrence

Memorial Maria Aragão / Oscar Niemeyer

Memorial Maria Aragão / Oscar Niemeyer. Image © Rômulo Marques
Memorial Maria Aragão / Oscar Niemeyer. Image © Rômulo Marques

Notes
[1] AMORIM; LICARIÃO, 2005, p. 23

Bibliographic References:
AMORIM, Adriana; LICARIÃO, Carolina. Introdução ao Conforto Ambiental. FEC/Unicamp.  2005. Available in: <http://www.fec.unicamp.br/~luharris/galeria/ic042_05/TIDIA-ae_TopicoA_mat-apoio_S03_C-Acustico.pdf >. Access in 11 Fev 2018.

About this author
Matheus Pereira
Author
Cite: Pereira, Matheus. "How Acoustic Shells Work (And How to Design Them Effectively)" [Como funcionam as Conchas Acústicas] 05 Mar 2018. ArchDaily. (Trans. Carvalho, Guilherme) Accessed . <https://www.archdaily.com/889713/how-acoustic-shells-work-and-how-to-design-them-effectively/> ISSN 0719-8884
© Matheus Pereira

四个实例告诉你如何做声学壳体?