© Matheus Pereira

声学空间的工作原理及设计策略
How Acoustic Shells Work (And How to Design Them Effectively)

由专筑网李韧，lj编译

声学壳体在世界各地的公共场所中都随处可见，它们拥有独特的形式，并且其功能也很有趣。声学壳体的设计灵感常常来源于人们的耳朵，其内部的声浪由它们的不同形式来决定，这种结构可以使观众听到的声音更强更逼真。

就技术来说，声音通过声学壳体的凹面而传播，换句话说，在声音发出后，经过壳体内部的反射，再传递向各位观众，另外，建筑师Chu Ming Silveira设计的巴西某款手机也运用了同样的原理。

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.

Image Complexo Concha Acústica de Brasília

Image © Gonzalo Viramonte

在声学壳体的设计中，其结构应当视具体情况而具体分析，因为不同空间所使用的的结构不尽相同，但是一般来说，声学壳体结构通常是一个以观众席中某一点为圆心的空间形体，抽象来看就是一个侧放的圆锥体，因此，这个圆心到壳体结构中的任一点的距离基本上是固定的。有的形状也许无法做到这一点，但是一个成功的声学壳体应当尽量遵循几何原则，运用马鞍形或波峰形都是不错的选择，一般的声学壳体由半圆形底座与抛物线形开口共同构成。

然而，还有其他一些因素会对声学壳体的有效性产生影响，通常来说，声学壳体所对应的地面应当具有一定的起坡，这样能够拥有很好的可视性，所以观众座椅通常呈放射状排布。同时，气候条件的影响也至关重要，如果当地的风速超过15公里/小时，那么就会对声音的传播造成干扰。[1]在设计中，还应该考虑环境材料，因为有的自然材料（例如草地）会吸收部分的声浪，而有的材料（例如水）却是声音的天然反射装置。

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.

Image Cortesia de Flanagan Lawrence

许多现代建筑师已经设计了颇具代表性的声学壳体，其中有奥斯卡•尼迈耶（Oscar Niemeyer）、Henrique Mindlin、Décio Tozzi等等。如今，这种系统的使用范围越来越小，因为它们已经被运用现代声学技术的封闭剧场建筑所取代。以下是一些曾经在Archdaily发表过的混凝土声学壳体设计：

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 /奥斯卡•尼迈耶
Acoustic Shell of Brasília / Oscar Niemeyer

Image © Gonzalo Viramonte

Parque Agua Azul声学壳体修复项目/ S2 Arquitectura
Rehabilitation of the Acoustic Shell of the Parque Agua Azul / S2 Arquitectura

Image © Carlos Garza

声学壳体/弗拉纳根劳伦斯
Acoustic Shells / Flanagan Lawrence

Image Cortesia de Flanagan Lawrence

Memorial Maria Aragão/奥斯卡•尼迈耶
Memorial Maria Aragão / Oscar Niemeyer

Image © Rômulo Marques

注释：
[1] AMORIM; LICARIÃO, 2005, p. 23

参考书目：
AMORIM, Adriana; LICARIÃO, Carolina. Introdução ao Conforto Ambiental. FEC/Unicamp.2005.
网址：
http://www.fec.unicamp.br/~luharris/galeria/ic042_05/TIDIA-ae_TopicoA_mat-apoio_S03_C-Acustico.pdf
参考时间：208年2月11日

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

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


出处：本文译自www.archdaily.com/，转载请注明出处。