ALLEGRO_MIXER - Allegro 5 API
typedef struct ALLEGRO_MIXER ALLEGRO_MIXER;
A mixer mixes together attached streams into a single buffer. In the process, it
converts channel configurations, sample frequencies and audio depths of the
attached sample instances and audio streams accordingly. You can control the
quality of this conversion using ALLEGRO_MIXER_QUALITY.
When going from mono to stereo (and above), the mixer reduces the volume of both
channels by sqrt(2). When going from stereo (and above) to mono, the mixer
reduces the volume of the left and right channels by sqrt(2) before adding
them to the center channel (if present).