You can play lullabies while sleep tracking to help you fall asleep better.

You can use:

  • lullabies supplied with Sleep as Android
  • buy a Lullaby pack
  • play any sound file in the background using your media player

Sleep as Android will automatically turn down the system volume once it detects you being deep sleep.

What are lullabies?

Lullabies are special long-playing audible compositions which help you fall asleep. There effect is very similar to listening to pure white noise but the environments (Sea, Whales, Chants..) used in Sleep as Android are richer and induce pleasant fantasies which further help sleeping.


Lulabies aren’t pre-recorded but rather automatically generated out of short samples. This makes each lullaby playback a unique experience.


Lullaby sounds

Lullabies are composed of repetitive sounds and sudden sounds.

Repetitive sounds are important in the process of making your brain tired and sleepy. Sudden sounds help to form a complete and unique environment and stimulate your fantasy.

For example the Diving with whales lullaby which you can listen to in the video is composed of:

  • repetitive low frequency deep water sound
  • sudden sounds of various whales, aqualung bubbles and breathing

First lullabies were designed as mostly nature sounds (mountain stream, summer storm, sheep counting, north wind, frogs, summer night, lava lake, baby in belly…), but over the time we have also added calming industrial sounds (steam train, submarine) and music (piano, flute, tribal drums, humming…).

There are 5 lullabies which arrive for free with Sleep as Android, 5 additional lullabies available after unlocking the app and many more with the Sleep Lullaby Add-on. We keep on adding new lullabies into the add-on all the time.

In Settings > Lullaby > Sudden sounds volume you can control volume of the sudden sounds. The overall volume of the playing lullaby can be controlled with your hardware volume keys.

Turn off when sleeping

This feature allows to use any sound or music source on your device as a lullaby. You may either use the build in lullabies as mentioned above, or you can start any of your sound player apps and gradually get to sleep. This feature controls the system-wide volume level and turns it gradually down when you fall asleep.

The mechanism is based on the sleep phase data from sleep tracking. Whenever we sense movement we postpone the volume down process for a while but if you are still awake you can always manually increase volume any time.

CAUTION: This feature only works when Sleep tracking is active

Binaural beats

You can mix special real-time generated binaural tones into your lullaby playback. Binaural tones are based on the same principle which is used in Mind machines (aka Psychowalkmans). This technique is based on stimulating your brain wave frequency by playing a slightly different tone frequency in each of your ears.

NOTE: Binaural beats are only effective if you use the lullaby with headphones.

CAUTION: We do strongly discourage users from using binaural beats if they suffer epileptic or cardiac issues!

Binaural beats used in Sleep as Android are either stimulating Your mind for relaxation or deep sleep starting at binaural frequency 20Hz and finishing at 4Hz or 2Hz. If You are interested in more info on this domain, You may consider trying out our complete Mind machine (aka Psychowalkman) implementation for Android called Mindroid.

TIP! You can also configure stimulating binaural beats into your alarm sounds for faster wake up.

NOTE: There are diverse opinions on the binaural effect. Alhough there are scientific studies which support the phenomenon in general, binaural beats are not considered as scientifically proven. Still we believe that the binaural functionality in Sleep as Android and Mindroid is interesting and provides a straightforward way to test this technique for yourself and to make up your mind on this matter.