The body is part of the external world, continuous with it. In fact, it is just as much part of nature as anything else there—a river, or a mountain, or a cloud.
—Alfred North Whitehead, Modes of Thought

Moving from light and birdsong into a roaring, resonating darkness, the shift is immediate, an all-consuming cavernous feeling that increases and then recedes. Cars and trucks cease making vehicle sounds and become an acoustic assemblage of road-bridge-concrete-steel-underpass-tire-weight-speed. A resonant boom overwhelms. Felt more than heard, it is totalizing—enveloping and imbuing. It is all light and shadow and volume. Resonating qualities rather than any particular thing, the sudden inability to focus on something is unsettling, disequilibriating.

I listen with steel and concrete and dirt. I listen with the water of the river that pools at the bottom of a sloping bank of concrete. I listen with the air that holds the rank scent of compost and the chemical smell of the L.A. River, the scent of cleaning solvents used in the waste treatment plant just upstream that provides most of the river’s water. Plants and trees grow on islands of sediment where herons, egrets, ducks, and other water birds with thin spiky legs make their home. But here under the bridge, there is only concrete, and the birdsong that accompanies us as we walk to the park is no longer audible.

The sound is concrete’s movement. Its permeability, its aerial entanglement manifest through motion and pressure—weight as a force, the touch, as it were, of tires. And while concrete allows cars to cross the river, suspended, as it were, in the air, it is itself less solid than it may appear. Once a liquid goop, in its hardened form it decays, cracking and chipping, and becoming, if not sand, at least rubble. The road rattles and roars, the clang of moving metal plates and friction of wheels on asphalt blurring in their auditory encounter. Perceived but not yet rendered legible, the underpass is “a living world possessed of a thickness, a mysteriousness, unknown elements and magical milieux” (Bonnet 2017, 86). It is dark and dank here, cooler than in the open air. Infra, inchoate, and indefinite, it is liminality as such, “a realm of pure possibility whence novel configurations of ideas and relations may arise” (Turner 1967, 97; see also McLean 2013, 60). Or, as McLean (2013, 62) offers, the between is “a superabundant plenitude, overflowing our received explanatory categories.” This underpass is not outside or under or even between—it is just right here where we are.

In the recording a shift in sonic quality is registered, but the perceptual confusion is lost—I now hear sounds of vehicles overhead, bicycles passing by. The microphone hears sounds, but not acoustics. It renders sensible what is perceived as “infra”—“that which slips through” or “escapes,” the “unqualified . . . vanishing . . . scarcely noticeable, faintly sketched things” (Bonnet 2017, 84). Instilling a clarity to the frequencies that make it possible to distinguish one sound from another, the recording brings a legibility to the space—the ability to read it, rationalize its features. It seems to me that a bass frequency in the resonance of the bridge itself is what gives the space its distinct quality—a bass frequency that is felt more than heard, and that is not in the microphone’s range.

A space to pass under, to move through, with “under” referring to the space of sidewalk, the bank that might be concrete or dirt or plant, the underside of the freeway and the air within—an emergent assemblage of concrete and air. An underpass presents itself as terrain vague, or what might be categorized as “blank space . . . ellipsis spaces, empty places, free space, liminal spaces, spaces of indeterminacy, spaces of uncertainty, vacant lands, voids, Dead Zones” (Doron 2007, 10). An underpass is intrinsic to the freeway, present whenever it has to go over anything—another road, a river, itself. Overpasses assert the totality of the freeway, gracefully thrown into the sky, arcing back into itself. And though the underpass also designates the freeway’s aeriality, less is said about this side of it. Ubiquitous yet off limits, it is nonetheless well used. It is a canvas for graffiti and sometimes sanctioned murals. If acknowledged, the underpass is generally cast as abject—an overlooked space of abandonment, its inhabitants glanced at peripherally if at all, whether out of a sense of compassion or discomfort. These days the sidewalks of most underpasses in L.A. are lined with tents.

Though its form is that of “underpass,” there is something unique about this one, this underpass that is also a bridge. The dirt, the booming resonance, the steep concrete bank of a river now part of an extensive flood control system of storm drains and channels and reservoirs. For some reason this one, which seems to me weirder and more uncomfortable than others, is more heavily policed. The fence is a barrier to habitation, and regular cleaning removes traces of human presence.

As my eyes adjust to the darkness and my ears take over from a vibrating body things begin to emerge, a variegated texture of matter becoming more apparent. A hill of dirt rises from the bike path to the undersurface of the freeway as it spans the L.A. River on its way to the Pacific Ocean. Two gullies are riven into the hill where water is allowed to flow. There are objects on the slope. Today the ones that differentiate themselves more or less are:

A pink plastic prescription bottle, empty

A cigarette pack, empty

A few pieces of blue cloth, hardened with mud

Discarded spray paint cans

A yellow rope hangs from a bar overhead; looped around and around, it ends in a tangled knot. Someone had to have put it there. Maybe those who tagged the insides of the I-beam supports, just where the bridge meets the embankment, MUTE and BIAKO, empty spray paint cans left in the dirt.

But . . . here, where I turned up the gain, my ears feel a pressure that exceeds the sounds as such. Perhaps an audio recording can convey something of this place. Or at least create a certain sensation of its own. Because a representation is also a composition. Not the acoustic space of the bridge per se, it is nonetheless sensed, bridging or “interweaving” (Whitehead 1938, 45) the sensible and its remainder, the latter a “surplus” that “runs through us and and insinuates itself into our relation with the world, without ever submitting itself to identification, without ever taking on sufficient form to be named” (Bonnet 2017, 79). A man’s reverberating voice amplifies the acoustic space, conveying something of a perceptual quality not captured by the recording.

There are other indistinguishable things, not yet differentiated from dirt that appears as “space” but is also “thing”—its tan color and dusty surface mounded and contained by a chain link fence that stops larger clumps as they fall, but not the slow seep out the bottom, dusty dirt edging out into the shoulder of the bike path. Dirt that is ground but not milieu, as it is also matter in motion (Latham and McCormack 2004; Anderson and Wylie 2009). A few days later I notice a patch of something green growing, small green leaves, too soft and delicate to be an intentional groundcover. It grows in an upside down V, a triangle of color against the gray brown of dust. When it rains these gullies are awash with trash—food wrappers and plastic bottles and tires and anything else tossed out a passenger window. One holds a concrete channel, now dislodged and partial, but seemingly once intentional. The gullies are de facto storm drains. A small collection of objects remains where the water runoff pools: the sole of a shoe holding on to scraps of its covering, a plastic milk bottle, an iced tea can. The other side of the bike path is smattered with pigeon poop.

We don’t like to linger here, though some people do. A flat lip of concrete at the bottom of the river bank provides a place to sit and fish, or write, or think. When we do stop, the palpability of the sound withdraws, becomes a sea of vehicles, some heavier than others, some faster, some slower. The traffic never lets up, but it is differentiated—there is a texture to it, and differences in the way various vehicles move the bridge. Some weigh heavily on a metal plate that clangs, others ride on the surface, the friction of wheels and road less.

I ask a sound artist friend for help. He brings his blimp and audio interface. He asks me where I hear it the most, whether the direction I’m facing matters. We point the microphone toward the crevice of the embankment. He explains that it picks up more high end, along with the bass. Together, they create something closer to the sense of the space, an auditory approximation of the somatic. The dirt absorbs and sounds become resonance.

Sometimes people stay here, under the bridge. Last week a woman had parked her shopping cart near the farther gully, settling herself into the puddle of water that had collected where the slope of dirt met the pavement. She had things lying around her, and I could sense a kind of obsessive engagement with them as I walked by, trying not to intrude on the space she had made for herself. After a few days, she passed on or was moved on. A few weeks later someone has made a space to sleep, arranging a sleeping bag on the ground between the chain link fence and a shopping cart full of things. A shopping cart that became a wall of two shopping carts, a suitcase, and a baby stroller, all overflowing with clothes and blankets, things proliferating across the bike path in a pile of pens and pencils. They had restitched a hole in the fence with sun-bleached tree branches, making a cross in the gap where dirt had been dug out, still too small for a person to crawl through. And then they were gone, leaving a stroller shade designed to look like the upper part of a shark head, red, with black eyes and a row of pointed white teeth.

On the way home the sun is setting and the concrete supports glow golden in its rays, square by square by square, alternating dark and light like a single line of a chessboard or a Judd wall piece tipped on its side. Formal resemblances rather than metaphor. Lit, they shimmer, amazing in their radiance.