The AUUG Motion Synth App release 1.3 and up include a selection of in-app instrument sounds.
NOTE: If you are upgrading from a installed app version lower than 1.3, please follow these "Updating to version 1.3 and above" steps.
These sound include an orchestra, clarinet, flute, choir, guitar (multi-key app version), and bass synth (multi-key app version).
For advanced users, these in-app sounds can be selected within the Notes Tab (Main Menu), however, these sounds will only work as intended if the correct the motion-to-sound setup is configured within the Motion Tab (Main Menu). For users wishing to understand and experiment with this motion-to-sound setup for these in-app sounds, advanced configuration details are available here.
If you are using the Motion Synth as a MIDI controller and don't want to use these the In-App Sounds, you can save battery life by ensuring that the In-App Sounds are turned off in the Notes Tab (Main Menu).