While SDL has an API that is designed for a low level software audio mixer, the excellent mixer library is much easier to use, and supports numerous sound formats, including WAV sound samples, and MOD and MIDI music files.

First, you initialize the mixer library and open your audio device:

if (Mix_OpenAudio(frequency, format,
                  channels, chunksize) < 0)
  {
    fprintf(stderr, "Can't open audio: %s\n",
            SDL_GetError());
    exit(1);
  }

• "frequency" is the quality of the audio (like 22050Hz, 11025Hz, etc.).
• "format" determines how many bits (8 or 16), byte order (LSB or MSB), and whether the samples are signed or unsigned values
• "channels" can be set to 1 for mono, or 2 for stereo
• "chunksize" is the size of a buffer used internally by mixer