Deep brown noise that never comes round again.

Why it works

This is brown noise with a second filter closing at 180 Hz, so what remains is mostly felt: the register of a ship's engine several decks down. Recorded versions of this sound are usually a few minutes long and joined end to end. This one is calculated as it plays and has no join.

Depth is restful and also completely empty. There is nothing in it to follow, which is fine until the thinking starts. The second fader adds something to follow: one voice, reading something true and unhurried, with nothing at stake and nothing to remember in the morning.

What you are hearing

• Deep brown noise. The same brown noise low-passed at 180 Hz. Almost everything above a cello's lowest string is gone. It needs headphones or a real speaker.
• The voice. The first four minutes of Aristotle, the Greatest Philosopher, a Lullable story, in a synthesised voice. It only plays if you bring it in.
• The ending. The preview lasts four minutes. Its last ten seconds are a straight fade to silence, so it never stops abruptly.

For a real recording that runs forty minutes, the Lullable iPhone app has rain, waves, a campfire and plain noise, with no voice and no music.