4.1.3 Mix_CloseAudio

void Mix_CloseAudio()

Shutdown and cleanup the mixer API.
After calling this all audio is stopped, the device is closed, and the SDL_mixer functions should not be used. You may, of course, use Mix_OpenAudio to start the functionality again.
Note: This function doesn't do anything until you have called it the same number of times that you called Mix_OpenAudio. You may use Mix_QuerySpec to find out how many times Mix_CloseAudio needs to be called before the device is actually closed.

Mix_CloseAudio(); // you could SDL_Quit(); here...or not.

See Also:
4.1.2 Mix_OpenAudio, 4.1.6 Mix_QuerySpec