Manufacturing Parametric Acoustic Surfaces
SmartGeometry 2010
Barcelona, Spain
Image Source: Brady Peters
The Manufacturing Parametric Acoustic Surfaces (MPAS) project was installed at the SmartGeometry 2010 Workshop and Conference titled “Working Prototypes”. The project was a collaboration between Brady Peters and Martin Tamke (CITA). The two primary goals of this project were the creation parametric models that adjust their geometry to effect acoustic performance, and the manufacture of acoustically active structures using digital fabrication techniques. Building on previous work, this project utilized both computational design tools and integrated acoustic simulation and modeling software directly into the design process. This project attempted to define more sophisticated objectives in terms of acoustic performance. Instead of just using reverberation time as the sole measure of acoustic performance, this project developed a more complex understanding of acoustic space through designing for multiple acoustic performance parameters, defining space through differentiated acoustic conditions, and creating sonic perceptual gradients. Different types of acoustically modulating components were assembled together to form a larger structure. The installation had a designed acoustic performance both at the level of the overall structure, and also at the level of the individual parametric acoustic surfaces. Through the use of acoustic performance as a design driver, the use of digital fabrication techniques, and a more complex definition of acoustic performance, new forms and material compositions were explored. Through the linking of acoustic theory, the parametric design of material and geometry, and the digital fabrication of these structures, a "working prototype" was created.
Image Source: Brady Peters
The design concept was to create a multiple different types of acoustic spaces. The project is designed as a wall dividing a space, on either side of it two different materials, and two different acoustic conditions. When this wall is curved, the number of potential acoustic conditions increases and a quiet, enclosed space is created. This enclosed space has less volume, more absorption, and therefore less reverberation time though it would still be strongly acoustically coupled to the main space. This enclosed space is a "dull" acoustic space. By modifying the geometry of the wall a sound focusing element is created thus creating a zone of amplified sound intensity. The modulation of material properties of the surface from one condition to another creates a gradient of acoustic performance from one space to another.
Image Source: Brady Peters
A parametric model of the design was developed. The parametric model allowed for the modification of the form of the structure and surface. Individual parametric models or computer programs could then be used to generate different panel strategies to populate the surface and structure with acoustically modulating components. Fabrication data was output from a custom notching algorithm. The strategy of multiple design tools that all work within the same design space allowed for new options to be easily explored. The parametric model was used to generate options and these options were then tested for acoustic performance and fabrication feasibility. Acoustic testing was done using Odeon, and fabrication feasibility was done with 1:20 scale models and 1:1 joint details.
Image Source: Brady Peters
Though the design of the form of the MPAS installation was completed prior to the workshop, the design of the individual acoustic panels was done during the workshop. The panel types and their distribution were informed by the acoustic design strategy. Nine different panel types were developed. The most basic type was the acoustic absorber panel. Two types of perforated screens were developed. The gradient perforated screen modulated the absorption of sound from the fully absorbing sound panel to a completely reflecting surface with little to no sound absorbing qualities. A sound scoop investigated a directional strategy where sound was absorbed from one direction and reflected back into the space from the other direction. A sound window component was developed. This component allowed visual connection from one acoustic space to the other. Three types of sound diffusing panels were developed.
The MPAS installation makes extensive use of digital fabrication methods. No drawings were created for the construction of the installation. Two laser cut models served as assembly diagram and panel distribution map. In order to have as much acoustic effect as possible, the installation had to have a large area and be massive. To be as absorbing as possible it had to maximize its surface area, and to limit sound transmission, be as heavy as possible. The structure and panels of the installation were made from laser cut 18 mm medium density fiberboard. 50 mm specialist sound absorbing foam was used as the primary acoustic absorbing material. Most of the sound diffusing acoustic panels, the sound windows, and sound scoops were CNC cut from 4 mm aluminum plastic composite sandwich material. The perforated screens were laser cut from 4 mm plywood.
The MPAS installation makes extensive use of digital fabrication methods. No drawings were created for the construction of the installation. Two laser cut models served as assembly diagram and panel distribution map. In order to have as much acoustic effect as possible, the installation had to have a large area and be massive. To be as absorbing as possible it had to maximize its surface area, and to limit sound transmission, be as heavy as possible. The structure and panels of the installation were made from laser cut 18 mm medium density fiberboard. 50 mm specialist sound absorbing foam was used as the primary acoustic absorbing material. Most of the sound diffusing acoustic panels, the sound windows, and sound scoops were CNC cut from 4 mm aluminum plastic composite sandwich material. The perforated screens were laser cut from 4 mm plywood.
Image Source: Brady Peters
Unlike artists, architects rarely get the chance to engage with the construction and material we design for. However, this engagement with material and the experience of the phenomenon is critical for an understanding of the potentials of acoustic design. By designing and building with sound-modulating material, a deeper understanding of material and performance is possible. Validation and testing is an important part of performance driven design. By testing the results of our research we are able to determine if the methods we use to produce performance driven design are working. Perhaps the most important result of this project was that it worked. The material and geometry contributed to creating a noticeable acoustic subspace. The individual parametric acoustic surfaces were successful to varying degrees. The concept of the gradient absorber/reflector was successful as was the acoustic window.
The Manufacturing Parametric Acoustic Surfaces (MPAS) project finds new potentials in acoustic-driven design. It looks beyond acoustic performance as a single value to acoustic performance as a differentiated field of values. The project considered multiple acoustic parameters such as early decay time and sound level. During the design process the acoustic performance was explored through using acoustic modeling and simulation software, by using form-generating computer scripts based on statistical formula, through listening to auralizations of the installation, and through experiments that acted on the acoustic material itself. Acoustic simulation and modeling proved to be an essential part of the design process if the design if the be informed by its sonic qualities. Parametric design and scripting tools can be used to explore not only singular objectives, but gradient conditions. While acoustic performance is often thought of in terms of singular performance criteria. This research suggested acoustic design, and sonic experience, can be enriched when it is understood in terms of gradients and multiple performance parameters.
The Manufacturing Parametric Acoustic Surfaces (MPAS) project finds new potentials in acoustic-driven design. It looks beyond acoustic performance as a single value to acoustic performance as a differentiated field of values. The project considered multiple acoustic parameters such as early decay time and sound level. During the design process the acoustic performance was explored through using acoustic modeling and simulation software, by using form-generating computer scripts based on statistical formula, through listening to auralizations of the installation, and through experiments that acted on the acoustic material itself. Acoustic simulation and modeling proved to be an essential part of the design process if the design if the be informed by its sonic qualities. Parametric design and scripting tools can be used to explore not only singular objectives, but gradient conditions. While acoustic performance is often thought of in terms of singular performance criteria. This research suggested acoustic design, and sonic experience, can be enriched when it is understood in terms of gradients and multiple performance parameters.