Stepping through the lobby and into the atrium of the San Francisco Museum of Modern Art (SFMOMA), I was greeted by strange sounds of dripping water, metallic pings and intermittent clicks. Just as I thought I could recognize the sound, it vanished. Sometimes it seemed to travel right before me, while other sounds seem to swerve somewhere nearby. It was hard to tell, though, as there was no evidence of anything around that could be making the noise — or so I was told. I cannot see and came to visit the museum with a number of friends, most of them also blind or visually impaired. We came to experience Sonic Shadows, the temporary site-specific sound installation by the acclaimed acoustic artist, Bill Fontana. We didn't know it at the time, but it was Bill's work that greeted us as we stepped toward the atrium.

Standing on the atrium floor with the occasional sonic beam buzzing by, we had the opportunity to hear about the installation from the artist himself along with Rudolf Frieling, SFMOMA's curator of media arts. We heard of the challenges of curetting an audio installation of this type, the artistry and inspiration that formed the work, and the technology that brings the art to life. In the end, of course, we were there to enjoy the art and the new dimension that it offered in the iconic atrium space of the museum — making the architecture audible.

The curator explained how he initially struggled with an installation that didn't follow the usual rules. It didn't stay within a frame, sit on a pedestal, or welcome containment of any kind. This art moved around the atrium and bounced randomly into all the spaces surrounding it. It ricocheted off walls, people, and other pieces of art. Patrons of the museum could be gazing at an artwork in a gallery on the second floor when a sonic beam might unexpectedly cross them. It is rare in a museum to let one piece of art sneak up invisibly to surprise visitors while they are focusing intently on another work. As irreverent as it may seem, Sonic Shadows created a wonderful temporal experience while one was immersed in the work through many different settings and evolving acoustic dimensions.

The piece seemed especially fascinating, funny, and even subversive when learning that the sounds ricocheting around were sounds that the museum originally paid good money to exclude from the visitor experience. They were sounds captured in real time from the boiler room — the mechanical loft — on the roof above the atrium as well as from footfalls of unsuspecting patrons walking across the steel bridge 5 stories above. Noises that were never meant to be heard within the museum were then the very sounds animating and enlivening the most celebrated public space of the institution. Liberated from the confinement of the mechanical loft, the noises became eerily serene whispers that seemed to resemble natural sounds from the environment, like streams, or dripping water.

To capture the sounds, Fontana placed a series of sensors with accelerometers on pipes and other equipment within the mechanical loft and also upon the steel truss of the bridge. The signals from these were then relayed to a computer, where they were mixed and composed by a program built to randomize the sound samples. From there the sounds were transmitted through ultrasonic speakers on the fifth-floor turret bridge that rotate and shoot sound waves like laser beams out into the atrium space.

The sounds were imperceptible until the sonic beam would bounce off a surface, striking you or somebody else. The effect could be described as a mosquito or large flying bug that buzzes straight at your head, quickly coming at you with a crescendo before it fades off into another direction. My wife had a chuckle when, walking toward the bridge the first time, she saw one of my blind friends, who is typically calm and composed, ducking and weaving as if avoiding punches thrown by a phantom boxer. This uncharacteristic behavior quickly stopped when he realized that it was the audible art that was whirling by.

Most interesting to us as patrons without sight was the way that the ultrasonic beams bouncing off the walls demonstrated the shape of the architecture that we could not see. Standing on the bridge, you could hear the geometry of the space as the point of inflection of the ultrasonic beam on the wall rotated around you. This sensation was quite successful in defining the space at the immediate level of the bridge, but less so relative to the height and depth of the space. Descending the stairs, however, we started to recognize larger "spots" of sound that seemed to move faster the lower we went toward the lobby floor. There in the lobby, we could better perceive the difference in the size of the audible spot and the speed at which it traveld, which gives a wonderful sense of the height of the space when compared to the sounds that are heard from the bridge way overhead.

Reflecting on the art after leaving the museum, I started to relate Sonic Shadows to Alexander Calder's red-and-white mobile in the East Wing of the National Gallery in Washington, D.C. Just like Sonic Shadows, Calder's kinetic art moves in and out of your consciousness as you move around the museum, catching occasional glimpses of the art through openings and in vistas across the gallery spaces. Sonic Shadows, however, was far less predictable, had a far greater reach and a richer composition. It had no visible form or mass, yet it seemed more physical and more immediate or personal to the observer.

I understand that in the absence of any other visible form for the installation, many patrons spent a lot of time gazing at the armature and array of speakers that moved and rotated above the bridge. That seems a bit like going to a movie and watching the projector. I suppose it's a rather curious visible contraption. Perhaps one had to look at it to try to figure out what it was.

However, I suspect that this may have been a piece of art that was best "seen" with your eyes closed. It is commonly held that 80 percent of the environmental sensory experience is visual. That's not to say that there are more visual phenomena in the world than there are sounds, tastes, touches or smells, but rather that the brain is disproportionately focused on visual stimulation. With a properly functioning visual apparatus, the brain is simply overwhelmed with sights, leaving little capacity to focus on or appreciate a comparable experience of sound. To have fully appreciated Sonic Shadows, then, it seems to me that it would have helped to block out the visual stimulation that would distract the sighted mind from really hearing the art. Doing this might have provided a better sense of hearing the surrounding architectural form. I referred many sighted friends to the museum to experience Sonic Shadows but challenged them to stand still on the bridge and close their eyes to really listen to the space. Then, I encouraged them to try it again on another floor to hear the differences.

Somehow, I can't help but wonder how many museum patrons recognized the sound installation as art. When I listened to people walk across the bridge, most crossed without pausing and didn't seem to notice the sounds whirling past them. Perhaps the sounds are just lost — like a bird singing outside a window. A most amazing sound or song might get filtered out by our brains focusing on a task at hand or on the art at which we may be looking. If we subconsciously ignore the birds and other ambient sounds, are we prepared to recognize or appreciate sound as art — especially if it has little or no visual evidence and is devoid of melody, lyrics, or rhythm? In the curatorial composition of the museum, it was a wonderful addition to find art that engaged other senses than simply that of the eye. It made the museum a richer experience for all.

Experiencing Fontana's "Sonic Shadows" as it celebrated and enlivened SF MOMA's most iconic space with its most forbidden sounds was fascinating, ironic, and fun. "Sonic Shadows" gave the SF MOMA atrium a dimension and dynamic that it never had before. It was also the most engaging acoustic and architectural experience that I have had since losing my sight. Regrettably, the installation was temporary and although the exhibit was extended, it has since been removed. For me, now, the museum seems to have a sad case of laryngitis. It was beautiful when the walls could sing.

Bill Fontana's "Sonic Shadows" was commissioned by and on display at SF MOMA from November 20, 2010 through November 6, 2011.