The Sound I remember: Investigating the Creve Coeur Aeolian Resonance
Updated: Sep 24
Some investigations begin with a question. This one began with a sound I had not heard in nearly twenty years. I was watching a YouTube video about unexplained sounds when one of the examples stopped me. Beneath the more obvious noise was a sustained, hollow tone… airy, distant, and strangely familiar. It sounded enough like something I remembered from childhood that I immediately began searching for other recordings.
Suddenly, I was thinking about Creve Coeur, Illinois, and the noise I used to hear at night behind my childhood home.
The Sound Behind the House
The sound was difficult to describe then, and it is still difficult to describe now. It resembled the tone produced by vehicles crossing a distant highway bridge, but it was smoother and more continuous. It was hollow without sounding empty, high enough to be clearly tonal, and distant enough that its direction was difficult to judge.
It did not sound like ordinary machinery. It did not pulse or fluctuate the way wind howling through a window does. When it was present, it seemed to remain remarkably steady… as though some enormous, hidden object had begun to resonate.
As a child, I assumed it was traffic or simply a noise that forests made. The sound seemed most noticeable during the colder part of the year, roughly from autumn through early spring, when the trees were bare. I do not remember hearing it when snow covered the ground, but snow absorbs and scatters sound so effectively that this absence may itself be meaningful.
Years later, I asked my mother whether she remembered the sound. She did. That does not tell us what produced it, and two people from the same household are not enough to establish how widely it could be heard, but it matters: the sound was not solely an internal sensation or an isolated childhood memory. At least one other person who lived in the house remembers hearing it too.
There was very little immediately behind our house: woodland, drainage infrastructure, Coal Creek, and, although I did not understand its significance at the time, the remains of an extensively mined landscape.
Falling Down the Historical-Map Rabbit Hole
Once the memory resurfaced, I did what any reasonable person would do: I opened Google Earth and fell completely down a rabbit hole.
Creve Coeur and the surrounding area sit over the abandoned workings of the Lake Erie Coal Company mine. Historical mine maps show underground rooms, passageways, a main slope entrance, escape routes, and several air shafts beneath areas that later became neighborhoods, businesses, roads, and woodland.
[Historic Lake Erie Coal Company mine map showing the documented underground workings beneath Creve Coeur. Source: Illinois State Geological Survey, Coal Mines in Illinois database. Cropped and annotated by Indigo Hart for research and commentary. Accessed September 2026.]
Using historical aerial photographs, modern satellite imagery, mine maps, terrain data, and old reports, I began trying to align the former mine with the landscape I remembered.
That process has uncovered some genuinely interesting features:
probable locations of the mine’s main slope and ventilation shafts;
surface features that persist across decades of aerial imagery;
old access routes still visible through vegetation;
unusual clearings and circular paths;
drainage structures and buried stormwater infrastructure;
and possible remnants of concrete structures associated with the abandoned mine.
[An in-progress Google Earth research map of Creve Coeur using historical imagery dated April 2, 2005. Colored paths, overlays and placemarks compare documented mine workings and access points with roads, drainage features and possible surviving surface structures. Candidate locations remain provisional and are labeled by confidence level. Base imagery © Google and its data providers; research annotations by Indigo Hart.]
Some of these features may be related to mining. Others almost certainly have more ordinary explanations. A circular mark in a field can be produced by mowing equipment, drainage work, buried utilities, or repeated vehicle movement. A suspicious-looking depression is not automatically a collapsed shaft.
The goal is not to force every unusual feature into a single theory. It is to document what is actually visible, compare it with historical records, and label uncertainty honestly.
What the Official Abandoned-Mine Report Documents
An Illinois Department of Natural Resources abandoned-mine report provides considerably more detail about the Lake Erie site than the historical map alone.
According to the report, mining began there in 1900 under the Progressive Coal Company. A sloped entrance reached the Springfield No. 5 coal seam approximately 90 feet underground. The mine later became the Lake Erie Mining Company and ceased operating on February 15, 1939.
The documented main site included approximately three acres of mine refuse, concrete foundations and footings, an abandoned paved access road, and a large concrete foundation measuring roughly 20 by 30 feet. The report states that this structure appeared to contain a deteriorating cap or floor and may have been connected to the former slope entrance.
More importantly for this investigation, the report documents three air shafts:
The first was described as approximately 1,300 feet south of the main slope, although investigators could not identify it conclusively during their field inspection.
The second was located in a ravine roughly one mile southeast of the main site. The report describes settlement approximately five feet deep across an area about 30 feet in diameter, with concrete rubble around its perimeter.
The third was located farther southeast at the base of another ravine. Its concrete fan housing had collapsed, and two pipes emerged into the ravine that investigators believed originated from the shaft.
[Excerpt from the Illinois Department of Natural Resources abandoned-mine inventory for the Lake Erie Mining site. The report documents the former slope entrance, three air shafts, a collapsed fan housing, and pipes apparently originating from one shaft. Cropped for research commentary; accessed September 2026.]
None of this proves that the abandoned mine produced the sound I remember. The report does, however, establish that the landscape contained multiple former ventilation openings, substantial concrete structures, ravines, pipes, and altered drainage pathways. Those features make airflow, structural vibration, water movement, and sound transmission reasonable possibilities to investigate rather than purely speculative ideas.
When an Abandoned Mine “Breathes”
While researching the Lake Erie mine, I encountered the term mine breathing. It sounds supernatural, but it describes a real physical process. A large underground mine contains an enormous volume of air connected, sometimes imperfectly, to the surface through entrances, shafts, fractures, drainage pipes and collapsed workings.
When atmospheric pressure changes, the air trapped underground can expand or contract. Falling barometric pressure can cause a mine to exhale, while rising pressure can draw outside air inward. Temperature differences between underground and surface air can also establish natural circulation between openings at different elevations. Government research into abandoned mines explicitly describes deep mines as “breathing” during barometric changes and documents substantial quantities of air entering or leaving large mine systems.
That moving air does not automatically produce an audible tone. However, if it passes through a narrow shaft, damaged seal, pipe, crack or partially obstructed entrance, the opening could behave like the neck of a bottle or the edge of a whistle. The underground passages would then provide a large resonating volume while the surface opening shaped the sound. Changes in air speed could alter its loudness or pitch.
One particularly unsettling example appears in the video Creepy Sounds Captured in an Abandoned Mine While Reviewing the ThruNite TN12 Flashlight, recorded inside the abandoned Waldeck Mine in Western Australia. Beginning around the twelve-minute mark, the explorer hears a fluctuating, breathlike sound reverberating through the workings. At approximately 12:12, the overlapping echoes sound uncannily, to me, at least, like the mine is asking, “Do you see me?”
That apparent phrase is an excellent example of auditory pareidolia: the brain’s tendency to organize ambiguous sounds into familiar speech. The recording contains irregular broadband noise and several resonant frequency bands. Reflections from the walls and branching passages stretch and overlap those sounds in ways that resemble vowels and whispered syllables. Other plausible contributors include airflow, displaced gravel, dripping water, wildlife or noises created by the explorer’s movement. Nothing in the recording establishes a paranormal or even specifically barometric source, but it demonstrates how startlingly voice-like ordinary mine acoustics can become.
Could the abandoned Lake Erie workings have breathed through their surviving shafts, drainage pipes or fractures? Physically, it is possible. The official report documented three air shafts, a collapsed fan structure and two pipes apparently emerging from one shaft. What remains unknown is whether enough unobstructed underground space and airflow survived during the years I heard the Creve Coeur Aeolian Resonance. Mine breathing therefore remains a possible airflow mechanism or acoustic pathway, not proof that the entire mine produced the sound.
What Kind of Sound Was It?
I initially began calling the sound a “Helmholtz resonance” because of its hollow, bottle-like quality. A true Helmholtz resonance occurs when air moves across or through the opening of an enclosed volume; the same basic effect produced when someone blows across the mouth of a bottle.
An abandoned mine, culvert, storm drain, ventilation shaft, or connected underground cavity could theoretically participate in that kind of resonance. But the name may not describe the precise mechanism responsible for what I heard.
The strongest comparison recordings I have found point toward another possibility:
wind-excited structural resonance.
When wind passes across regularly spaced railings, cables, slats, pipes, openings, branches, or other rigid objects, it can shed alternating vortices. Under the right conditions, those vortices excite a stable tone. If a nearby structure or enclosed space reinforces the same frequency, the result can become surprisingly loud and persistent.
The now-famous “singing” of the Golden Gate Bridge is an enormous example of this phenomenon. Wind passing through its redesigned railing produces a powerful sustained tone that can travel across the surrounding area. Manchester’s Beetham Tower provides another well-documented example: during strong winds, air passing over the glass fins of the decorative “blade” at the top of the building produces an unintentional hum or howl. The tower’s tone has been identified near the B below middle C, approximately 247 hertz, and has reportedly reached around 78 decibels. Although both examples differ in pitch from the Creve Coeur sound, they demonstrate that bridges, buildings and seemingly decorative architectural features can behave like enormous wind instruments.
[The Murray Baker Bridge, photographed from the East Peoria side of the Illinois River looking toward the Peoria skyline. Like other large bridges known to produce wind-excited tones, it is one possible source considered in the Creve Coeur Aeolian Resonance investigation, although no evidence currently links it directly to the sound. Photograph by Indigo Hart. February, 2021]
One especially close comparison contained a prominent tone near 490 hertz. Other similar recordings contained stable tones around 305, 363, 439, 480, and 519 hertz. The frequencies differ, but the texture, the quality that makes the sound feel recognizable, can be remarkably similar.
Following Similar Sounds Around the World
Once I had a clearer idea of what I was searching for, I began listening to recordings of unexplained hums, industrial whistles and wind-excited structures from around the world. They are often grouped together online as “the Hum,” but they are not necessarily manifestations of one worldwide phenomenon. Some are low rumbles, some are sharply defined musical tones, and some have ultimately been traced to ordinary machinery.
The Fort Greene Hum, Brooklyn, New York
The closest comparison I have found comes from Fort Greene, Brooklyn. Residents described a sustained sound resembling a finger circling the rim of a glass or a vibrating tuning fork. It could continue for hours, disappear and later return, and was frustratingly difficult to locate.
The resemblance is more than subjective. In the news recording I analyzed, the strongest sustained tone measured approximately 466–467 hertz. The prominent tone in my Creve Coeur recording falls around 448–456 hertz. A difference of only about three percent.
A confirmed source for the Brooklyn sound was never publicly announced. One resident elsewhere in Brooklyn reported that city environmental-noise investigators heard a similar sound but measured it below the threshold required for further action. According to that resident, the investigators suspected rooftop heating or ventilation equipment. That remains an unconfirmed explanation rather than a solved case.
Industrial Tones in Texas
Recordings uploaded by the YouTube user ldavidsontx document work around industrial coal-handling equipment in Texas. Beneath the obvious mechanical noise is a surprisingly musical, airy tone. In one recording it begins around 530–600 hertz, descends as the machinery or airflow changes, and settles near 490–500 hertz.
This is not an unexplained community hum: the industrial setting is plainly visible. It is valuable because it demonstrates how machinery, moving air and surrounding metal structures can combine to create something that sounds uncannily like a distant wind harp. The audible tone does not necessarily come directly from a motor. Machinery may instead supply the airflow or vibration that causes another structure to resonate.
The Auckland Hum, New Zealand
The Auckland Hum is one of the closest comparisons in overall character, although its documented frequency is much lower than the tone from my memory. Researcher Tom Moir recorded a low-frequency signal with a prominent component reported near 56 hertz.
To my ears, recordings of the Auckland Hum share some of the same distant, hollow and strangely enveloping quality. Nevertheless, the large frequency difference means that it cannot be treated as an acoustic match to Creve Coeur. Similar timbre does not necessarily mean an identical physical source.
The Taos Hum, New Mexico
The Taos Hum became one of the most famous examples of “the Hum” during the 1990s. Hearers generally described a very low-frequency drone, sometimes compared with a distant diesel engine. A formal investigation failed to identify a common acoustic, seismic or electromagnetic source.
Taos is important to this investigation mostly as a cautionary example. Reports from sincere witnesses do not automatically establish that everyone is hearing the same external signal. The Taos phenomenon is also substantially lower in frequency than the Creve Coeur tone, making it an imperfect comparison despite the shared word hum.
Kokomo, Indiana
Kokomo provides an example in which investigators actually found significant industrial noise sources. A study associated one component near 36 hertz with a cooling tower at a DaimlerChrysler casting plant and another near 10 hertz with an air-compressor intake at Haynes International. Modifications were made, although some residents continued reporting a hum afterward.
This case shows both the usefulness and limitations of identifying machinery. A city can contain multiple tonal sources, and eliminating two measurable signals does not prove that every resident’s experience had one cause.
The Windsor Hum, Ontario and Michigan
The Windsor Hum was eventually localized toward the industrial operations on Zug Island, across the Detroit River in Michigan. Canadian research found evidence pointing toward blast-furnace activity, although investigators could not isolate the precise component responsible. Reports largely ceased when steelmaking operations on the island stopped.
Windsor offers strong evidence that an industrial installation can create a sound that travels across a wide area, crosses an international border and remains extremely difficult for listeners to locate. Its heavy low-frequency character, however, does not closely resemble the clearer mid-frequency Creve Coeur tone.
The Forest Grove Sound, Oregon
In 2016, residents of Forest Grove, Oregon, reported a piercing nocturnal tone variously compared with a flute, faulty brakes and a “mechanical scream.” It vanished before investigators conclusively identified its source. Later acoustic analysis made an HVAC-related source a plausible explanation, but no specific machine was confirmed.
The Forest Grove Sound is higher, sharper and more variable than what I remember. Its disappearance nevertheless demonstrates one of the central difficulties of studying environmental sounds: by the time enough people begin recording and investigating them, the equipment or atmospheric conditions producing them may have changed.
The Woodland Hum, County Durham, England
Residents of Woodland, a village in County Durham, reported a persistent hum in 2011. Environmental-health officials investigated, but no universally accepted external source emerged. Like Taos, Woodland is usually discussed as a low-frequency Hum case rather than a close pitch match for Creve Coeur.
Woodland initially interested me because I had once wondered whether bare trees, cold air or the forest itself produced the sound behind my childhood home. Its name turned out to be geographical rather than evidence that woodlands naturally generate this particular tone.
The World Hum Map
I also searched the community-submitted reports collected by the World Hum Map at thehum.info. The nearest report I found was in Peoria Heights, approximately seven miles from Creve Coeur. That person described an intermittent nighttime sound resembling an idling generator or diesel truck and estimated it at approximately 200 hertz.
Its proximity is intriguing, but it does not establish a connection. The report began years after I left Creve Coeur, describes a substantially lower pitch and includes no recording that could be compared with mine. Other scattered reports and Reddit discussions have the same limitation: they show that people around central Illinois have noticed unusual sounds, but not that they heard the sound I remember.
The Closest Matches Came from Illinois Ethanol Plants
After searching through recordings from around the world, the closest examples I found were not famous hums at all. They appeared in footage of two Illinois ethanol plants: the former ADM plant in Peoria, now operated by BioUrja Renewables, and an Abengoa Bioenergy facility in Madison, Illinois.
The Peoria footage contains a sustained industrial drone with a hollow, mechanical quality. A second news report, filmed outside the Madison ethanol plant after an emergency, contains an even closer example. Behind the narration and other activity is a faint, airy tone that continues through much of the exterior footage. One portion sounds like an unmistakable alarm or siren, but the quieter background resonance can also be heard outside that passage.
[Headphones are encouraged for these videos.]
An informal spectral comparison placed the recurring Madison tone around 448–454 hertz, overlapping closely with the approximately 451–456-hertz tone in my Creve Coeur recording. The Peoria footage also contained tonal energy in the same general range. These figures should not be treated as calibrated scientific measurements: the clips have passed through news production, YouTube compression and screen recording.
There is another major limitation. Both videos were associated with emergency responses. The sounds could have come from temporary alarms, fire engines, pumps, idling vehicles or other emergency equipment rather than ordinary ethanol-plant machinery. Nothing in either video proves that the plants normally produced those tones, or that the former ADM plant caused the sound I heard as a child.
Even with those qualifications, these recordings illustrate the Creve Coeur Aeolian Resonance more accurately than the East Peoria warning-siren video did. Their tones have the same distant, hollow and airy character I remember. Ethanol plants also contain large fans, blowers, dryers, compressors, ducts and steam systems capable of operating for long periods, making an industrial source more consistent with the sound’s apparent duration than a brief warning-siren activation.
Taken together, these cases do not reveal one universal cause. They instead show several ways a neighborhood can acquire a mysterious voice: cooling towers, compressors, ventilation systems, industrial furnaces, resonating metal, wind-excited structures and atmospheric conditions that carry distant tones farther than expected. The Brooklyn recording remains remarkably similar, while the Illinois ethanol-plant footage currently provides the clearest example of the particular hollow, airy quality I associate with the Creve Coeur sound.
The Forest May Have Changed the Sound
It is also possible that the forest did not create the tone but helped deliver it.
Bare trees, cold air, creek valleys, and nighttime temperature inversions can all affect how sound travels. A source some distance away may become audible in one location while remaining faint or unnoticed elsewhere. The Coal Creek corridor could have acted as a pathway, while leaves present during warmer months may have scattered or masked some of the higher-frequency sound.
This could explain why the tone seemed associated with the woods even if its actual source was a bridge, ventilation structure, utility installation, industrial machine, storm drain, or something else
The nearby abandoned mine remains relevant, but not necessarily because “the whole mine was humming.” Mine shafts, capped openings, old concrete structures, drainage modifications, and later infrastructure built across the former mine property could all have interacted with wind, water, machinery, or transmitted vibration.
Has Anyone Else Heard It?
As part of the investigation, I searched the thehum.info , a volunteer-built database where people around the world can report persistent, unexplained humming sounds.
[An anonymous Peoria Heights report submitted to the World Hum Map on April 4, 2019. The reporter described an intermittent nighttime sound resembling an idling generator or diesel truck and estimated its frequency at approximately 200 hertz. This is the closest geographically relevant report I found, but it remains self-reported and does not establish a connection to the Creve Coeur Aeolian Resonance. Screenshot from thehum.info; accessed September 2026.]
The geographically closest report I found was in Peoria Heights, approximately 7 miles from Creve Coeur. The person reported beginning to hear the sound in 2017 and described it as resembling “a generator or diesel truck idling outside.” They estimated its frequency at approximately 200 hertz and said it was loudest indoors at night, usually between 10 p.m. and 3 a.m. It was intermittent rather than constant, sometimes appearing once or twice a month, sometimes several nights in one week, and sometimes disappearing for weeks. The reporter also said that other people had heard it at the same place and time.
That is intriguing because of its proximity, but it does not closely match every part of my experience. The Peoria Heights report describes a lower, more engine-like sound at approximately 200 hertz. The closest recorded comparison I have found for the sound I remember contains a much higher sustained tone near 490 hertz. My sound also seemed associated with colder months and the wooded area behind my childhood home, while the Peoria Heights reporter did not recall a clear seasonal pattern.
I found a couple of other anecdotal mentions on Reddit from people who remembered unusual humming around the greater Peoria area. However, none included an audio recording, frequency measurement, precise location, or enough descriptive information to establish that they heard the same sound I did.
For that reason, I consider these reports leads rather than confirmation. “A hum” is a broad description that can encompass industrial equipment, ventilation systems, electrical infrastructure, distant traffic, tinnitus, low-frequency vibration, and wind-excited structures. Two people hearing unexplained noises in the same region does not automatically make those noises one phenomenon.
Still, the Peoria Heights entry establishes something worth remembering: at least one other person in the Peoria area independently reported a persistent nighttime hum, and they were not the only person able to hear it. Whether that report has any connection to what I have provisionally named the Creve Coeur Aeolian Resonance remains an open question.
What I Know VS What I Do Not
At this stage, I have not identified the source.
I know that the sound was not mine alone; my mother remembers hearing it too. I know that Creve Coeur contained a substantial abandoned underground mine with several surface openings. I know that the neighborhood had significant drainage infrastructure. I know that similar sustained tones can be produced by wind interacting with built structures. I also know that local geography and seasonal atmospheric conditions can make distant sounds behave in unintuitive ways.
What I do not know is whether anyone outside our household heard the same phenomenon, how far it traveled, or which, if any, of these facts explains the sound behind my childhood home.
The strongest regionally relevant comparisons I have found so far appear in recordings made outside ethanol plants in Peoria and Madison, Illinois. The Madison footage contains a faint recurring tone in approximately the same frequency range as my recording, while footage of Peoria’s former ADM plant contains similar sustained industrial noise. More importantly to my ear, both have a hollow, distant and airy character that resembles what I remember more closely than the outdoor-warning siren recording did.
Neither recording identifies the source of that sound. Both videos were connected to emergency incidents, so alarms, fire apparatus, pumps, idling vehicles or other temporary equipment may have contributed to what was recorded. The audio was also compressed and was not collected under controlled conditions. These clips therefore cannot establish that ethanol-processing machinery produced the tones, much less that the former ADM plant caused the sound behind my childhood home.
They do, however, demonstrate that industrial environments can produce remarkably similar sustained resonances. A fan, blower, compressor, dryer, duct or other rotating system could operate much longer than a warning siren and generate a stable tone that changed character as it traveled. For now, the former ADM plant and other machinery along the Peoria river-and-rail corridor remain plausible industrial candidates, but not final answers.
Memory is not a calibrated microphone, and the recordings I am comparing were made years later in other places. A similar sound is evidence of a possible mechanism, not proof of a shared source. Any responsible conclusion will require more than recognizing a tone in a video.
For now, I am continuing to map the mine, examine historical aerial photographs, document surviving surface features, and search for municipal drainage records and old photographs. I am also collecting recordings of structurally produced tones to better understand which mechanisms can create the particular combination of steadiness, pitch, distance, and airiness that I remember.
I may eventually discover that the explanation is an entirely ordinary piece of infrastructure.
Honestly, that would not make it any less fascinating.
A sound that once seemed to belong to the forest has led me through abandoned coal mines, forgotten roads, aerial photographs, acoustic physics, storm drains, wind-induced vibration, and landscapes transformed almost beyond recognition.
The research is unfinished. That is precisely why I wanted to begin documenting it now.
Sometimes curiosity does not begin in a laboratory or archive. Sometimes it begins late at night, when a video unexpectedly returns you to the woods behind your childhood home and you finally decide to ask what, exactly, you were hearing.
