Melomania earbud settings such as which Audio Mode, default EQ presets and Codec are stored directly on the earbuds. Therefore if you change these settings on the Melomania app and then connect your earbuds to another device, the settings will still be applied.
Be advised that any of the three Custom EQ profiles are unique to the device that they were changed on, so any changes made to custom EQ parameters will not carry over to another connected device (that has the Melomania app installed).