In school, the architect鈥檚 study of acoustics is categorized as building science, squeezed between calculations of light and thermal performance. We learn that sound is physical energy, measured by calculating pressure waves and managed via applied surfaces and construction assemblies which then dissipate the pressure waves.
In professional practice, we remember to hire an acoustic consultant聽to process the 鈥減roblem鈥� of sound for us. Framing sound as an engineering problem, however, ignores its potential.聽Sound cannot be avoided or solved, but it can be harnessed.
In the year following my building science course I visited Nijo Castle in Kyoto, Japan, home to Ninomaru Palace, a building housing a series of large tatami-floored rooms where shoguns would meet with advisors and visitors. Long hallways of bare wood floors surround the rooms and connect the outermost public spaces with private interiors. There is no way to walk on the specially attached boards without triggering them to squeak or 鈥渃hirp.鈥� Our professor explained that the sound of the floorboards served as an ancient ninja proximity alert system. The legendary floors became known as the uguisu-bari, or nightingale floors.
As a young architecture student, I was blown away. Sound became a functional wall that deterred intruders. The likelihood of detection (the floor makes a louder sound when you apply lighter pressure) meant that assassins were not willing to risk a break-in. The phenomenon of the floor鈥檚 sound transformed into a conceptual tool, a means for changing behavior: sound as invisible power.
We are all routinely behaving in response to sound鈥攐ften without realizing that sound is the driving factor. The subconscious effect of sound has been well-documented, and we know from the history of Muzak, a company that dominated the 鈥榖ackground music鈥� industry for several decades in the mid-20th century, that people are easily manipulated by background sounds. Part of the impetus for the company itself was the way its founder, a World War I general, was inspired to keep soldiers calm by sending music to army camps via electric wire.
Today, background music in our retail environments is explicitly manipulative; shoppers are being led to stay longer and buy more. In the extreme, sound is weaponized. If architects and designers accept the power of sound with more clarity and responsibility, we can begin to ask how sound could function as a positive element of architecture, not just the default result of people using a building or 鈥渘oise.鈥� How could we think additively about sound, not just about its reduction or removal?
For a workplace for Indicate Office in San Francisco, we used the code-mandated fire corridor as a space to encourage a 鈥渟ound walk鈥� by embedding transducers鈥攊nvisible speakers鈥攊n the walls. This created a calm, transformative environment for workers seeking a break. The corridor feels much farther than it physically is from the rest of the office due to this transportive quiet.
Elsewhere in the office, we also transformed a giant wall into an ambient speaker, its vibrations disrupting the often-uncomfortable void of sound that plagues open offices. This is just one example, but it extrapolates easily鈥攁t the limits of architecture, sound can add more to our work.
Each visual component of architecture has a sonic counterpart. Think about a programmatic study, for example. Through the lens of sound (even our metaphors cannot escape the visual bias), we can have meaningful conversations about user groups, demands on space which are time-based, and ideal adjacencies among building users. If we permit sound to have more weight in these early design conversations, we can even save some work that the acoustic consultant has to perform later on, such as designing a wall to keep one high-volume program element apart from one that demands more quiet.
On a recent trip to Japan, I returned to Nijo Castle to experience once again the origin of my sonic turn as an architect. It turns out the nightingale floors weren鈥檛 created on purpose. They are a side effect, a happy accident, of the flawed way the floors were built. I spoke with a Japanese preservation architect at Nijo Castle about the origin of the nightingale floor. Numerous other temples around Kyoto employ the same construction technique, including Nanzen-ji and Ryoan-ji. When this technique is applied to newly replaced sections of floor, they do not sing like the aged nightingale floor does. I walked on some of these newer floors and indeed there was no sound. This result has led the preservation architect and other historians to believe that the sound is an accident and not an intentional design, though the effects of the 鈥渕istake鈥� resulted in the sonic protection of the shoguns. Such is the nature of many acoustic improvements in our world. We learn about them through trial and error, in constant reminder of the fact that sound powerfully impacts space.
When architects pivot their thinking on sound from nuisance to tool, learning more from our mistakes, we can begin to embrace its power. We have an obligation to think of the potential of sound to enhance architecture鈥攂ecause if you don鈥檛, your project is at risk of becoming the next nightingale floor. It could very well ruin the experience of what you have built, unless of course you meant to design a ninja proximity alert system. As one Australian tourist remarked: 鈥淚f these floors were in my house, they would drive me crazy.鈥� Why leave sound design to chance?
Imagine instead that we can hear what our spaces will sound like before we build them. Some acousticians have this capacity via spatial audio software, and I have also worked with ambisonics, a format for 3D audio, to project virtual architectural spaces. It is not far-fetched to hear, in the near future, sounds rendered by architects as easily as we render light.
Nick Sowers is an architect based in Seattle and runs the practice Timbre Architecture & Sound.
