While music is playing (it is obligatory) on tiltle or in game, changing music volume changes sound volume as well.
When music stops playing (e.g. on title) sound volume become freezed on the level it was set by 'music volume' slider until new music starts playing (or something is reset; not sure about this, I simply started the game), i.e. if muic was toggled off on title, sound will toggle of too; increasing music volume when music is not supposed to play anymore will not restore sound.
This works both with and without OpenAL.