Stories ·
The Hum Beneath the City
Somewhere under the tram lines there's a note that never stops. We spent a winter trying to tune to it.
The first time we heard it, we thought it was the fridge. The second time, the fridge was unplugged and the hum was still there: a low, patient B-flat, a little sharp, coming up through the floorboards like warmth. By the third night we had a contact microphone taped to the skirting board and a notebook open, and we’d stopped calling it a fault.
Every city has one. Engineers call it mains hum, the 50-cycle tremor of alternating current that leaks into every amplifier ever built.1 But what we heard sat lower and wider than that, and it moved. On cold mornings it dropped by almost a semitone. On Sundays, when the trams ran less, it thinned out and you could hear something inside it, like a second voice humming harmony.
Tuning to the floor
The studio is in an old print works, two floors above a substation. Tracing the hum to its source took no detective work, only patience. We wanted to know whether a city’s undertone could be played with. Can you write in its key? Can a record agree with the building it was made in?
So we tuned everything down. The piano went first, a quarter-tone flat, which made it sound older and sadder. The guitars followed. The synthesizers were easy. The voices were hardest, because a voice tuned to a building sounds like it’s apologising to the walls.
What the meters said
We logged the hum for ninety-one nights. The numbers matter less than their shape. The pitch tracked the temperature closely and the weekday traffic loosely. Once, during a city-wide outage that lasted eleven minutes, it went away completely. Those eleven minutes are the quietest thing we have ever recorded. We listened back to them more than to any of the music.
| Condition | Average pitch | Drift |
|---|---|---|
| Weekday, below 0 °C | 116.2 Hz | ±0.4 Hz |
| Weekday, above 10 °C | 118.9 Hz | ±0.7 Hz |
| Sunday | 117.5 Hz | ±1.9 Hz |
| Outage | — | — |
A record that agrees with its room
First Rites is what came out of it: three pieces that sit on top of the hum instead of fighting it. Played anywhere else, they sound slightly out of tune, like a photograph of a room you’ve never been in.2 Played in the studio, with the windows shut and the substation breathing below, they sound finished.
We don’t know whether that’s a flaw. We do know that when we finally moved the desk away from the wall, the painting behind it looked different, cooler, as if something had been switched off.