In recent years there has been a three-day street festival each fall in San Francisco called the Market Street Prototyping Festival, organized by the city and the Yerba Buena Center for the Arts. The organizers commission people to create installations and exhibits and interactive happenings to be put in place all up and down Market Street. I was part of a team that created a big sound installation for the 2016 festival under the sponsorship of San Francisco’s Center for New Music. Our assigned location was near the corner of Market and Sixth Street. The installation remained in place for the full three days of the festival, and a huge number of people engaged with it. That location is in the Tenderloin district, a part of the city with no shortage of interesting characters. 

[Update inserted Oct 2021: In the years since its first appearance as described in this post, Play Hear or elements thereof have appeared in various locations, including a long stint at Bridge Storage and Artspace in Richmond, CA. There it boldly withstood weather and wonderful creative kid onslaughts for a few years before it we finally decided it was time to dismantle it after a long and fruitful life. Here is as video of the installation being played just before that final disassembly. Several parts of Play Hear have since then found a new home in Sudhu Tewari’s excellent street-front sound garden in Berkeley.]   

Public art has some unique requirements, and this is especially true of interactive sound works. Such a work must be completely bomb-proof, of course. This means that it must be undamageable even by kids or drunks. It must be completely safe, meaning that no matter how crazy people get, they cannot injure themselves on it. It has to be un-stealable: the whole thing either has to be either permanently fixed in place or so big and heavy that even someone with a pickup truck couldn’t make off with it. Likewise all parts and components have to be unremovably attached to the whole if they are not to disappear. Outdoor works have to be weatherproof.  This means not only that they must be made of dependably all-weather materials – a serious restriction for many sound-instruments – but also that they can’t have any crannies where rainwater could collect, mosquitoes breed, or critters enter, make nests, or die.

Such installations also must be ADA compliant. This refers to the Americans with Disabilities Act, which requires wheel chair accessibility and several other features pertaining to safety and access. And here’s another consideration that hadn’t occurred to me until I was told: installations approved for this festival were not to have any enclosed or partially enclosed areas in which someone can’t be seen from the outside – no spaces where someone might urinate, shoot up, or engage in sexual activity. Also, to be successful, a publicly interactive sound art piece needs to be reachable and playable by little people and big people, tall and short, young and old. There should be no special skills required in the playing of it, no musical training necessary. It should be obvious in how it works: if people can’t see immediately what to do with it, they won’t engage. It needs to be loud enough to overcome street noise (quite a challenge in some locations, if you’re not going big-time amplified), but not so loud as to create unwanted disturbance or run afoul of noise ordinances.

It also has to fit the sponsor’s budget, and not require fabrication techniques that aren’t available to the makers.

Have I missed anything?

This is a daunting set of requirements! Most seemingly promising sound-making ideas run aground on one or another of these expectations. Those ideas that make the cut often are dishearteningly commonplace or trivial.

So here’s what we did in our attempt to make something that would meet the above requirements, and yet be fresh and interesting.

The installation included six different instrument types, all of them tuned to the same scale. The tuning was inspired by the fact that the date of event was near the centennial of the birth of West Coast composer Lou Harrison, who is something of a cultural hero for many around here. In his honor, the chosen scale was one that he devised, a very appealing five-tone just intonation scale modeled after Indonesian slendro scales. The installation was built around three free-standing walls, positioned at angles to one another and braced in such a way that they were quite stable.  The walls helped define the space, creating a sense of being within the installation (but the space was still open enough to avert the afore-mentioned problem of possibly concealing unsanctioned activities). The walls also served as mounting structures for the instruments, and as soundboards for some of them.  They had peekaboo holes, which made it possible to play from the inside some of the instruments mounted on the outside of the walls, as well as adding to visual interest and a fun inside-outside dynamic. In addition, there were some playable musical benches on the opposite side of the space facing the walls, marked “Sit or Play.”

One of the instruments was a set of angklung.  Angklung, originally from Indonesia, are sections of bamboo sounded by percussion, carved to a special shape which allows tuning of both the percussion tone of the bamboo and the resonance of the enclosed air column.  With the air resonance tuned to agree with the bamboo percussion sound, the tone is fuller and more satisfying than would be a bamboo segment without air tuning. For each note of the Lou Harrison scale there were four identically tuned bamboos, suspended like chimes with golf-ball beaters suspended between them. If the bamboos had been within people’s reach, they would have been vulnerable to damage, so to get them out of the way, the bamboo assemblies were positioned at the top of 12-foot upright boards attached at the base of one of the walls. While the bamboos remained well out of reach, people could sound them by pushing at people-height on the uprights boards. This made the boards to flex and sway, causing the beaters to strike the bamboos in a motion a little like that of wind chimes. People approaching the installation saw signs placed down at human level on the upright boards saying “Push Gently.”  It was fun to see them notice the signs, then push the boards, and then look up in response to the unexpected sound from above. The audible effect was pretty, a sort of random flurry of resonant thunky sound, warm and woody. Since each of the six upright boards supported four bamboos all tuned to the same pitch, you could play melodies by pushing different boards in sequence.

Another of the instruments was a set of aluminum tubular chimes, set up high overhead in the same manner.  So while one person was melodizing with the bamboos, another person could use the same gentle pushing for a counter-melody in a sustaining metalic chimey sound. With the ongoing rocking of the upright, the scattering of chime tones tended to blend together, creating an effect not so much of individual strikes, but more like a steady stream of tone.

The musical benches – three of them — took the form of steel tongue drums mounted flush in a sittable bench-top surface. There were two of these circular tongue drums in each bench, each about nine inches in diameter, with three tongues per drum. (The drums were heavy and strong enough to withstand being sat upon). The idea behind the acoustic design was that the bench tops would function as sound boards, and the mostly enclosed areas beneath the benches (which had side panels to form the enclosure) would serve as resonating air chambers. This worked great: the tone of the steel tongue drums was greatly enhanced by the soundboard and box that was the body of the bench, yielding quite a lovely sound. I’m a little short of serious metal working skills myself, and much of the credit for the fabrication of these instruments goes to Ian Saxton, Sudhu Tewari, and Ben Carpenter. For several reasons, making and tuning these drums was quite a challenge, and, sadly, they didn’t hold their tunings under the onslaught of beating they received.  I do hope to spend more time with metal tongue drums sometime before I die; the very pleasing tone quality of these makes the idea worth pursuing further.

On another wall was a set of large spring-mounted stamping tubes. These were four-inch diameter tubes ranging from about four to eight feet in length, with protruding handles marked “Press down here.” Pressing down caused the closed bottom ends of the tubes to strike the hard pavement below, creating a jolt that excited the air in the tube. The big tubes made a pretty convincing sound when you were close to them, but on the noisy street, from any distance, the effect turned out to be not so great – lots of clacky-sounding percussion noise; not enough tone. Too bad. This was the least successful instrument of the bunch. It had another liability as well: had the installation been a permanent one, extending beyond the three-day festival and into the San Francisco winter, the tubes would have filled with rainwater.

Then there were the stomp flutes. This instrument consisted of a set of six fipple flutes, each about two to four feet in length, mounted on one of the walls. Each flute was connected to a foot-bellows by means of a flex tube – the kind of bellows used for inflating rubber dinghies and air mattresses and such – and the flutes were played by pressing on these with one foot. It turned out that some artistry was required to press down just right for a clear, steady tone: step a little too hard, and the tone would shoot off into upper partials in unpredictable and not-very-harmonic ways.  It bought home this fact about wind instruments, especially flute-like instruments: consistency of wind pressure is crucial.  In mouth-blown instruments players learn to control their breath just right in order to play well in tune and in the intended register. In organ-like instruments the makers and technicians control wind pressure and related factors with a high degree of refinement to get this just right. In the stomp flutes, no such refinement was happening, and the resulting tone was all over the place. Of course, everybody stepped too hard.  It was a unique and ear-catching sound, even if the pitches were not those of the intended scale. And people found it hugely fun. Several kids figured out that they could straddle two bellows at once, a foot on each, and do a kind of rocking two-tone musical dance. For grown-ups, it turned out that playing with two hands instead of one foot allowed much more control and facility, but doing so involved kneeling on some pretty grody pavement – something that fastidious people wouldn’t want to do. This instrument was conceived by one of the team members, David Samas, and the flutes were fabricated by Peter Whitehead. The instrument inspired me later to make a manual stomp flute using smaller bellows.

And then there were kalimba-like instruments mounted on the walls. The generous sound-radiating surface that the wall afforded allowed these instruments to project reasonably well, even in the lower frequencies. There were eight kalimbas, tuned to different parts of the musical range. They worked nicely when ambient street sound wasn’t too overwhelming, their melodic nature and pleasing timbre adding an attractive complement to the other instrument sounds present.  But even with the help of the generous wall board surfaces, they came up a little short in volume anytime the surroundings got noisy. This exacerbated another slight problem: in my wish to make these things sturdy enough for public use, I made the spring-steel tines relatively heavy and stiff.  This, combined with people’s attempts to play quite vigorously to compete with surrounding noise, made them hard on the fingertips.

And here’s the last of the instruments: Atop the whole structure was a big DeVore-style wind harp.  The late Darrell DeVore, a huge inspiration and spiritual touch-point for many instrument makers in the SF Bay Area, made something he called wind wands. They were a simple configuration of crossed sticks and flat rubber bands, played by waving them through the air. The rushing air causes the light-weight, flat bands to sing. Similarly, if mounted stationary in the right location they’ll sing in the wind, and this was the idea behind the wind harp atop Play Hear.  Admittedly, during the time of this installation it was rarely windy enough to activate the bands much, and in any case the street noise would have been enough to drown it out  – but it had an iconic look as the pinnacle of the structure there, and it was very nice to have a bit of Darrell with us. This part of the installation was the work of David Samas.


Three days spent at the corner of Market and Sixth with this structure was a memorable experience. Lots of families came by and engaged with it, lots of unbearably cute kids; lots of working people both white collar and blue who were happy for a lively distraction as they passed. Lots of street people, some seemingly more reality-based than others. Most were a pleasure to meet and interact with, while a few were difficult. As you’d expect there was a lot of uncoordinated exploratory noise-making on the installation, but there was also a good amount of musically aware and interactive jamming, including some pretty great musical moments. Interesting fact: in a random sampling of people on the street, a surprisingly large percentage have decent percussion chops. Quite a lot of people, seeing the installation, brightened immediately; they knew exactly what to do, and they went right to it. Anytime you get two or three or four such people together, some very satisfying grooves will emerge.


The Play Hear team consisted of: Adam Fong, David Samas, Sudhu Tewari, Peter Whitehead, Ben Carpenter and myself, operating under the sponsorship of San Francisco’s Center for New Music..



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