Sitting on a bench in the Dietrich Gallery of the Academy of Natural Sciences of Drexel University is unlike sitting on a bench anywhere else in the city — even those down on the banks of the Schuylkill, although that will change in August.

Bullfrogs rumble through the Dietrich, the benches capturing deep music pumping right through the wood; peepers are everywhere; geese create a frothy racket; water gushes through timbers retrieved from French Creek.

The Wissahickon runs through the Dietrich. And the Tulpehocken. The Perkiomen. And the Schuylkill, of course, as it curls from Tuscarora Lake and passes through Black Rock Preserve and down toward the Delaware.

This is the immersive world of sound artists and composers Liz Phillips and Annea Lockwood, who have created an exhibition unlike anything else in the academy’s long history — an ambitious sound installation, The River Feeds Back, which opened June 1.

The River Feeds Back, which runs through Oct. 30, amounts to an aural geography of the Schuylkill watershed, a glimpse of the river’s ecosystem, as captured by the ear. The artists recorded the river and its tributaries over 135-plus miles, from Tuscarora Lake near Barnesville in Schuylkill County, to the city, home of the bellowing geese at Valley Green on the Wissahickon.

Altogether, they gathered sounds above and below the waterline from 19 different locations.

Last month,Lockwood and Phillips were at the academy installing the exhibition, trying to balance the multiple sound tracks, no easy task when geese are blaring.

Honking filled the gallery. But suddenly geese stopped and a sound akin to a quiet, rustling of paper replaced the honks.

“We’ve now moved,” said Lockwood cocking her ear and explaining the audio transition. “We’re underwater now to bugs,” she said.

“Bugs,” echoed Phillips, “Yeah, these are insects chewing away there.”

Phillips, 70, knows the noise of bugs, although not so well that she can necessarily identify which bug she’s listening to at any given time, at least not yet.

“The bugs are very often so tiny as to be invisible,” said Lockwood, 82. “Sometimes I’ve recorded with the hydrophone right in clear water. Perfectly calm day. I can see the weeds. I can see the details of the weeds. And the bugs are making a tremendous racket and I can’t see a single one of them, really. They can be really minute sending up terrifically strong signals. They’re so fascinating.”

“And fish make a lot of sound, too,” added Phillips.

The sound of the bugs increased in intensity, crinkling through the gallery like a velveteen rasp.

“This is on the Tulpehocken, an old lock associated with the Union Canal,” said Lockwood, listening closely. “It’s really become a sort of large pond for all sorts of critters and I just put the hydrophone underwater and had some fun with it. All of this came up. It was a type of magic. You put it underwater, and all of a sudden, a totally different world is revealed from the world we’re used to.”

That is why Phillips and Lockwood will be installing a second part of their aquatic river portrait during the summer. Inside the Watershed — a listening station on the Schuylkill bank behind the Philadelphia Museum of Art — will open Aug. 3. Visitors will be able to hear the live sounds of the river there in real time.

“It’s like listening to a completely different world,” said Lockwood, describing the noisy river below the waterline.

Does she have a favorite creek, a favored part of the watershed?

“For me the Tulpehocken is my favorite,” said Lockwood, who was born in New Zealand, studied in Britain, and has lived in the United States for decades. She is a composer by training and inclination, and has been incorporating the acoustics of the world into her work for many years.

“It was absolutely beautiful,” she said of Tulpehocken. “It gave me some really interesting sound. You know, I hung out there, I based myself there for about four days, five days, not too long ago and just went out from there all over the place.”

The installations are part of a multifaceted academy project dubbed “Watershed Moment,” itself part of a larger academy initiative, Water Year 2022.

For Phillips, the Wissahickon Creek was a favorite.

“I also loved Black Rock,” she said. “At Black Rock we got a golden recording just last week. Now that the frogs are really croaking, we got a real, almost a summer recording. It was 95 degrees. So it was very early morning and the sound was just beautiful.”

Phillips hails from New Jersey and began her career as a sculptor. But she wanted something that would “immerse you in space.” Sound is what she came up with.

“I tried video,” said Phillips. “I tried lasers, and light things, and then I thought, ‘Well sound is the most tactile material that I can really control with electronics and put into a piece.’ But that was way back when the integrated circuit was first being invented. So you could actually make sounds and let them be in a space. Before that, the tape would break if you left it in an installation. So I really came out of sculpture into sound installation.”

Phillips and Lockwood have known each other for many years but never collaborated on anything before this project. But when the pandemic hit, rather than stay at home, they began meeting outdoors, in the middle of Westchester County, north of New York City, exploring its waterways with a mic.

This was in 2020 in the depths of the pandemic.

“We’d meet at all the sanctuaries and parks with water and put the hydrophone in and see what we could come up with,” said Phillips. “It was a day away from being locked up and be together — but not too close.”

Visitors to the Dietrich Gallery will be able to listen to The River Feeds Back — created more recently than the Westchester excursions — through the air and through a number of “listening portals” arranged throughout the gallery. Benches, hollowed tree trunks, a weathered tree limb, and pieces of slate embedded with transducers (devices that translate electronic signals into sound waves) — all will make a frog or a bug rumble and buzz in a highly visceral way.

Benches will vibrate and jiggle with every car that passes over a rickety bridge. The waters of the Schuylkill push the gallery around.

“Experiencing Annea Lockwood’s and Liz Phillips’ new work is a revelatory experience,” said Marina McDougall, academy vice president of experience and engagement. “The River Feeds Back gives voice to the Schuylkill.”

“The River Feeds Back” is free with admission to the academy, which is open Wednesday through Sunday, 10 a.m. to 5 p.m.