There’s a door in the fence just off Horticultural Drive between the Shofuso Japanese House and the Horticultural Center in Fairmount Park. Music is playing in my headphones as I lift the spring-loaded door and step through the threshold. Without adjusting the app on my cell phone, or even its volume, the music changes along the path circling the Pavilion in the Trees.

Actually, sequencing today’s ethereal soundtrack is mine to create. It just depends where I decide to roam.

Taking in Pulitzer-winning composer Ellen Reid’s Soundwalk in Fairmount Park is an experience of exploration and discovery. There’s an element of control for the listener – rather, composer – as much as there is one of powerlessness. Musically, it approaches improvisation, while seeing — rather, hearing Soundwalk — from a composer’s perspective, it toes the line of genre-shifting art.

“I like to think that the listener improvises with this work,” Reid says over the phone from Brooklyn. “And you’re the composer, too, because you’re deciding where you go and where you stay.”

Soundwalk is a GPS-enabled installation working through an app that spans from the Mann Center, southeast to Smith Memorial Arch and north to the Horticultural Center within Fairmount Park. Each “sound cell,” as Reid refers to the sections of the park covered by Soundwalk, contains a different piece of orchestral soundscape that interacts with each participant. As one walks through the cells, or stays within them, the music morphs. The intention is to create a different experience each time passing through.

Continuing along the path circling clockwise toward the Pavilion in the Trees the music is eerie and smoky. It’s mid-June, the sun is hot and the foliage is dense. That fence I passed through earlier is clearly succeeding at keeping deer out of this part of the park. There are long violin melodies and sparse percussion accompanying surprising, other-worldly vocals making some sort of anxiousness simmer inside me. At times it’s hard to tell which musical movements are changing on their own as the map on the app shows where the cells begin and end, while other cells have distinct changes from layered instrumentation but remain within steps of one another. And that’s how Reid intended it.

“I think music can be so mysterious,” she says. “I see the landscape as having a certain quality. Maybe it’s closed or maybe it’s open. Maybe it has a color. If you’re surrounded by tall trees with a lot of bark it has a different color palette than if you’re in Oregon and there are trees that have, say, red bark. There’s a combination of the elements that are in your visual surroundings and it’s about finding the ways to amplify them or push against them within the soundscape.”

Where the wooded area of Fairmount Park feels creepy, Interstate 76 is just within earshot as if just to remind that Soundwalk is still taking place within the city of Philadelphia. Hearing the environment, even if a bit grinding like the highway sounds, informs the path.

Members of the Philadelphia Orchestra contributed to Fairmount Park’s Soundwalk, as well. According to Reid, there are “very large and important moments that are realized by the Philly Orchestra.” All of which were recorded by themselves at home in the face of the COVID-19 pandemic.

“When I think of their virtuosity, not only do you have to be one of the best players in the world,” Reid says. “But you have to be a recording engineer, too. People were creative in the moment and that makes even the biggest challenges easy.”

Walking back towards the Shofuso Japanese House I veer off Lansdowne Drive, passing a group of teenagers taking cell phone pictures of each other. My awkward wave sufficed for friendly interaction with headphones still in my ears so to not miss any part of the Soundwalk, which is getting particularly spacey, maybe even psychedelic. I walk through overgrown pavers in the lightly wooded area leading to the intersection of Belmont Avenue and Avenue of the Republic to find what sound textures await.

It wasn’t the pandemic and its influence on people to get out into nature more that prompted Soundwalk into existence. A GPS-powered soundscape has been a project that Reid was interested in pursuing for years. The biggest hurdle she had to get over was finding the right app developer to help bring her vision to life. Meetings with techies repeatedly lead her to the same problem: being forced to have a single starting point and following the musical program in order. Reid likens the approach to walking through a museum exhibit one room at a time. Being able to walk through the park freely without losing the music and allowing the listener to decide what pieces of music to engage with was her goal. Echoes, an England-based app developer specializing in geolocating, was the perfect partner that brought her Centennial District soundscape to fuition

“I had to physically test all the music,” Reid says. “There was no way to mock that up. No way to feel that in my studio – to move through a soundscape or even remain stationary as it does to feel it if you’re actually in the location.”

The sun hasn’t let up beating down on me as I make my way around Concourse Lake. I’m careful that something supernatural isn’t stalking just behind me, or at least that’s the feeling Soundwalk is now imposing. It’s strange to realize I’ve passed this lake many times without paying any mind to it while on my way into the Mann Center for a concert.

“Frankly [Soundwalk is] bringing to life some parts of the Centennial district, that some people don’t know about,” says Catherine Cahill, Mann Center President and CEO. “But more importantly it was about giving back to the community while offering a new alternative to get out, get out of the house and experience our historical park, and a Pulitzer-winning composer’s work in a very creative and innovative way.”

Scaling synth lines drone in my ears as I walk back to the car, but not before going around the Horticultural Center. There the “Journeyer,” a towering statue that’s weathered on the surface, but conveys a strikingly wise traveler. He’s seen some rough things along his way and this afternoon I feel that I can relate. Arriving at the car parked outside the Shofuso House I’m greeted by thundering drums. I stop in my tracks as they seem to have come and gone like a gust of wind, because not even retracing my steps in the middle of the parking lot helps my ears find them again.

A moment such as this, never experiencing the music the same way twice, is exactly the moment that Reid hoped the Fairmount Park audience and audiences across the country would encounter. Soundwalk will be installed in its 11th city by September and with the geography being different at each venue, even Reid doesn’t know what to expect.

“I’m always surprised,” she says. “I think with Soundwalk it’s always a nice feeling when the soundscape matches the landscape. And I think it takes some diving in to get to the that place.”