Zug, winter 2028
Four years have passed since I first entered the bunker on the Zugerberg, and I am beginning to write these lines because someone — perhaps a child fifty years from now, perhaps a woman from a canton I have never been to, perhaps a man who tonight in Hamburg or Oslo hears the 103.7 hertz for the first time — will want to understand what happened.
Not the scientific side. That is in a paper which Steiner and David and Ruth and I published in September 2027 in Communications Earth & Environment, seventeen pages, fourteen authors, and which has since been cited one hundred and twenty-seven times. What is in that paper is precise, data-driven, cautious. It is what such a paper should be.
But what is not in it, is the story.
The people. The cassettes. The silence between two beats.
The afternoon in October 2024 when I stepped out of a steel door with thirteen cassettes pressed against my chest and was no longer the same person who had walked in five hours earlier. The evening in April 2025 when a hundred-year-old man in a house in Köniz said to me: Just be there. That is enough. The day in February 2027 when I went back up to the Zugerberg and in the forest met a woman who did not speak, only greeted me, and whom since then — though I know her and trust her courage — I have never been able to name, and never will.
That is the story.
I am writing it down now because it has begun to dissolve out of memory, the way recordings come loose from an old magnetic tape when no one plays them. Not out of vanity. Out of responsibility.
My name is Jonas Wirth. I am forty years old, I grew up in Cham in the canton of Zug, and I have been working with sound since I was sixteen. Tone, frequency, resonance. The way a room colours a voice. The way an instrument produces not only notes but time. The way a forest is not silent but made of layers you can uncover, if you have the right microphone and enough patience.
My father, Heinrich Wirth, had lent me his Tascam 424 when I was sixteen — a four-track recorder, dbx noise reduction, early nineties — and in the forest behind our house on Knonauerstrasse in Cham I had recorded the sounds other children did not hear.
Not the wind.
Not the birds.
The crack of the needle layer under a deer. The resonance of a hollow tree trunk when you knocked against it with your knuckle. The frequency at which the wood kept ringing, seconds after the strike.
Later I studied sound design at the ZHdK, specialising in field recordings, worked for two years in Bern, then opened a studio in Zug, at Bundesplatz, in the basement of an old building from the thirties whose foundations rest on molasse, just as the foundations of the whole city rest on molasse.
Molasse, that sedimentary rock from the Tertiary, formed thirty million years ago as the ocean which once covered what would become the Alpine region slowly retreated and laid down sand and silt and clay in layers that compressed under their own weight until they became stone.
Under Zug. Under Bern. Under Lucerne. Under Zurich, Solothurn, Olten. Under the entire Swiss Plateau.
And beneath this rock, as it turned out: a frequency.
A single, stable, constant eigenfrequency at 103.7 hertz, with an amplitude that sits psychoacoustically right at the threshold of conscious perception, and a periodic modulation every eight seconds that never measurably drifts.
The rock sounds.
