From where I stand it is a single copper thread, your doorbell, and it hums along its whole length at once: the mine it was pulled from, the wire coiled behind your wall, the green corrosion it will wear in the year the house comes down. You think of it as silent until pressed. I see the pressing already there, always there, a thousand fingertips laid over one small button like light through a leaf.
I can see you now, the way your shoulders lift a little when it sounds. That lift is the same lift you had at four, tearing down a hallway toward a door because the chime meant someone chosen was on the other side of it. You are still running. The hallway is longer now and your knees will one day protest the sprint, but the shape of the motion does not change, cradle to the last time you ever answer.
Here is the echo I love. In one place along your thread a small hand cannot reach the button, so an adult lifts the child up to press it, and the delight is enormous, world-sized. Farther along, that grown child stands on a step holding groceries, both hands full, and taps the button with an elbow, tired, expecting no one thrilling.
Same button. Same two notes falling. To me these press the same instant, and the wonder in the first has never gone anywhere; it is simply standing a little further down the wire.
You are worried, sometimes, that the people who rang will not ring again. From here I promise you they are all still ringing. The door is always just now opening.
Someone is always about to be let in, and it is always, in some room of the shape you are, you.