Modeling and Analysis
Conveying our ideas and recommendations at various points entails words, sketches, animations, and, at critical points, immersion in aural renderings of a room.
Threshold Auralization Studio
Sketches, diagrams, material samples, and computer modeling are combined to support the design vision.
Far beyond a means of presentation, modeling is a part of our day-to-day process. We embrace both physical and computer modeling, each of which has a place in design. In the early going, computer models of options and benchmark halls allow us to quickly evaluate the effects of differing audience arrangements on overall room volume and geometry. Modeling the benchmarks is as important as modeling the design options, translating listening experience in beloved halls into the virtual realm, thereby establishing a fair context for evaluation of the design options.
While acousticians are well trained in the technical vocabulary of sound, our clients and collaborators on the Design Team usually are not. Our work involves a deep knowledge of architecture and audio and video technology and a lot of math, but these are all means to an end. The conversation begins and ends with the subjective experience of our clients. We recognize our responsibility to avoid jargon and instead communicate in terms more accessible to those who don’t know our language. There are powerful, evocative parallels between sight and hearing: virtually everyone can understand the color black as perfect absorption, a diffuse reflection as a frosted mirror, or the randomness of sand rippled by wind or water.
Beginning the design conversation on an intuitive, metaphorical basis establishes a way of conversing that is difficult to leave behind – it seems unfair to demonstrate progress by statistical presentation alone, and nuanced differences between design options don’t lend themselves to evaluation by means of comparative graphs. Conveying our ideas and recommendations at various points entails words, sketches, animations, and, at critical points, immersion in aural renderings of a room. These ‘auralizations’ are far more intuitive as a means of evaluation, relying upon the ear rather than presentation of statistics. Acoustically modeling a room or a series of rooms allows us to quickly and iteratively evaluate the effects of variations on room shaping, interior materials, and isolation approaches.
Threshold’s Auralization Studio
In our studio, a twenty two-channel audio system and 4-meter diagonal video screen immerse listeners in a strongly visual and compellingly aural experience that we have used to evaluate theatres, concert halls, lecture rooms, lobbies, and social spaces. Musicians, singers, and actors that we have ourselves recorded anechoically can be heard in these rooms, compared to familiar benchmark spaces, and evaluated against each other, by eye and ear together. Haydn and Hindemith turn out to be far more accessible than charts and graphs; the experiential evaluation leads to insights that could not otherwise be reached; and many who enter the studio skeptical of their own hearing emerge with a new appreciation of it.
Experience has shown us that the evaluators should include musicians, artistic, technical, and administrative executives, architect and theatre consultant. The studio is arranged so that as many as 12 can participate at a time, allowing for a large group that can converse in real time as the simulations play.
As early design progresses, comparative modeling helps us evaluate refinements in seating planes, interior materials, and isolation approaches – quickly and iteratively – allowing us to run alongside the Architect. This is the profound strength of digital modeling. Elements of still greater detail – balcony fronts and surface diffusion, for example – can benefit from finite element analysis, mathematical modeling capable of evaluating even extremely fine-scale shaping. We use finite element analysis in combination with genetic algorithms, a means of quickly evaluating thousands of potential shapes through a mathematical process inspired by natural selection in the biological world. The finalists are evaluated with full size mockups to which we listen, sometimes with a voice or a violin involved, correlating the measurements we take with the sound we hear.
In the audio realm, modeling allows prediction of loudspeaker coverage and quantification of unwanted ‘spill’. The latter is as important to understand as the former, since spilled energy causes echoes and confusion indoors and irritates the neighbors outdoors. Mapping the energy onto wall surfaces in a room or onto the landscape and adjacent buildings for an outdoor venue help us select the most appropriate loudspeakers for the circumstances, often with the final evaluation of audio quality made by ear in front of the loudspeaker itself.
To the extent possible, the Client and Architect hear for themselves and participate fully in the decisions at hand. In this way, our projects benefit from different scales of evaluation, each of which informs those that come later. The moments of evaluation can be extremely powerful for everyone involved.
Software Integration
Projects like Springdale Pavilion (right) benefit greatly from current industry software standards. We use the same software as architecture firms, in this case Rhino and Grasshopper, to quickly collaborate and quickly iterate based on feedback, showing exactly how sound will react in the space based on those iterations until the best possible outcome for end-users is found.
For the uninitiated, Rhino 3D is a design tool that allows its users to render model curves as they exist, rather than faceting them. Grasshopper, used in conjunction with Rhino as a graphic scripting tool, gave us a means to simulate sound waves moving within an enclosure. It allows us to pick a source point and script a sequence of parameters that simulate wave behavior. These scripts are often pre-written but can be manipulated in different ways for every project. No matter the project, scripting allows for changes in real time and quick design approaches while working with the architect: a dialog can occur wherein we tweak the model, send it to the architect asking ‘what about this?’ The architect can then tweak it as well and send back with the response ‘how about this?’ with the end result being a space that sounds as good as it looks for the client.
We’ve found Grasshopper to be an incredible aid for the client as well as the design team. Using tiny bubbles to simulate the wave arrays in a space is an easily digestible visual aid. As the bubbles interact with geometry, one can see where they continue spreading, where they hit a curve, where the reflections happen in time and the intensity of those reflections at that moment. With the Springdale Pavilion, this allowed us to script different scenarios: natural sound sources at the stage level, with amplified sound from loudspeakers hung from the pavilion, with a totally reflective building material, with absorptive portions. From each iteration we could easily manipulate the shape of the pavilion and the placement of reflection and absorption materials. These iterations become a dialog, for example on the Springdale Pavilion with Trahan, as we worked together to discover the best design for the pavilion.
With any tool there are limitations. The distillation of wave behavior is, of course, a reduction of wave behavior just as an architect’s rendering is a snapshot of the lived-in reality. But even within limits, this software allows us the chance to show the acoustical responses of any would-be space, well before the space is built, to the benefit of everyone involved.