Flyby Synth1.7 - Google Play

Flyby Synth generates complex stereo sounds using FM synthesis (frequency modulation). They mostly have a noise-like quality, like science fiction sound effects.
You can save the sounds, e.g. to use them as Ringtones.

The generated sound is continuously modified by moving the space probe across the screen. This is typically done by tilting the phone or tablet. If this is not supported by the your device, then simply move the space craft's position by tapping the screen in different locations.

For best results slowly move the space probe all over the galaxy and stars on the screen passing through all areas of the screen at some stage.

For a different kind of sound manipulation change into Boost mode.

When listening to the sounds through your headphones or when plugging your phone into a stereo you get weird acoustical sensations.

If you like a sound you have just created press the Stop button, then open the menu (Menu button on your phone) and select the Save option. This way you can save the sound as WAV file to your SD card. You can also select whether you would like the saved sound to be used as Ringtone, Music, Alert or Notification (See Preferences Menu).

Troubleshooting
On devices with high-resolution displays the space probe movements, and hence the sound changes can be a bit slow. Speed up the movement by tapping on different parts of the screen.

App background image (galaxy cluster) and space probe image (Deep Space 1) courtesy of NASA.