There are several applications, games and Youtube audio videos that reproduce white noises, thus allowing the user more concentration or better sleep. Some of the sounds are also downloadable, so you always have them in portable devices, such as an MP3. Noise canceling apps can also filter out ambient noise or even blend it completely. With so-called noise cancellation, an integrated microphone records ambient noise. This is then converted into counter-sounds which neutralize the sound waves that occur. There are also headphones that cancel noise and work similar to apps.