The Hum Beneath the City

2026-09-30T12:00:00Z

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.

Plate II: Substation. Painted over the winter the hum was loudest. Oil and graphite on board.

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.

In Europe the grid runs at 50 Hz, so the hum and its harmonics sit at 50, 100, 150 Hz and up. What we measured was none of these, which is what made it interesting. ↩
Listen on headphones and you'll hear the faint second voice at about 1:40 into Invocation. We didn't put it there. ↩

Notes from the Tape Room

2026-07-11T12:00:00Z

A reel of quarter-inch tape holds about thirty minutes at the speed we use. That’s the whole budget for a session. You can’t scroll back through takes, so you play as if every take is the keeper.

Hiss is a texture, not a fault

Every pass through the machine adds a little noise. After four overdubs it sounds like weather. We used to fight it. Now we tune to it: we pick keys that sit comfortably on top of the hiss and let the quiet passages blur.

What the tape remembers

The machine is older than either of us. Its heads are worn into the shape of other people’s music, and you can hear that.