Noise or a story? Try each for a minute.

Why it works

People divide into those who sleep to sound and those who sleep to speech, and many have only tried one. Noise suits you if the problem is outside: traffic, neighbours, a house that ticks. Speech suits you if the problem is inside, and you lie in a quiet room being talked at by yourself.

The buttons above let you find out. The first is brown noise alone, generated live, with no loop. The third is the story alone. The middle one is both, and it is where a good many people end up: the noise for the room, the voice for the mind, and neither asking for anything.

What you are hearing

• Brown noise. White noise run through a leaky integrator, so its energy falls six decibels per octave, then low-passed at 400 Hz. A low, even wash.
• 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.