Notes about sound
The DIGMID wavetable driver uses standard GUS format .pat files, and you
will need a collection of such instruments before you can use it. This
can either be in the standard GUS format (a set of .pat files and a
default.cfg index), or a patches.dat file as produced by the pat2dat
utility. You can also use pat2dat to convert AWE32 SoundFont banks into
the patches.dat format, and if you list some MIDI files on the command
line it will filter the sample set to only include the instruments that
are actually used by those tunes, so it can be useful for getting rid of
unused instruments when you are preparing to distribute a game. See the
Allegro website for some links to suitable sample sets.
The DIGMID driver normally only loads the patches needed for each song
when the tune is first played. This reduces the memory usage, but can
result in a longish delay the first time you play each MIDI file. If you
prefer to load the entire patch set in one go, call the
load_midi_patches() function.
The CPU sample mixing code can support between 1 and 64 voices, going up
in powers of two (ie. either 1, 2, 4, 8, 16, 32, or 64 channels). By
default it provides 8 digital voices, or 8 digital plus 24 MIDI voices (a
total of 32) if the DIGMID driver is in use. But the more voices, the
lower the output volume and quality, so you may wish to change this by
calling the reserve_voices() function or setting the digi_voices and
midi_voices parameters in allegro.cfg.
