You can play calming sounds—such as ocean or rain—to mask unwanted environmental noise and help minimize distractions so you can focus or rest.
Go to Settings > Accessibility > Audio/Visual > Background Sounds, then turn on Background Sounds.
Set any of the following:
Sound: Choose a sound; the audio file downloads to your iPod touch.
Volume: Drag the slider.
Use When Media is Playing: Adjust the volume of the background sound when iPod touch is playing music or other media.
Stop Sounds When Locked: Background sounds stop playing when iPod touch is locked.