Creative SOUND BLASTER PRO User Reference Manual page 137

SOUNDBLASTER^
For our purpose here, we shall use the terms General MIDI to refer to
MIDI files. Under Microsoft's Windows with Multimedia Extensions, to
support devices with different capability, a MIDI file contains two sets of
MIDI events. The first set is located on the first ten channels and is for
Extended MIDI. The second set, the last four channels, is for Basic MIDI.
Only one event can be played at a time and is device dependent In
Extended MIDI, devices must be able to playback at least 16 melodic and
16 percussion notes. A basic device must play six melodic and five
percussion notes. (Refer to the Appendix for the MIDI capability of the
Sound Blaster ro's synthesizer chip).
MIDI files that are complex and have too many notes to be played at the
same time, might be beyond the hardware capability of the MIDI device.
However, the software driver attempts to provide the best possible output.
Variation in
Drum Channel
Another issue is the location of the drum (percussion) channel. Normally,
it is either on channel 10 or 16. This depends on how the MIDI file was
created and the software device used. Since there is no standard or fool ­
proof way to identify whether a MIDI channel is a drum channel, most
software programs assume the drum channel is at a predefined channel
or request the users to specify the channel.
Variation in
Instrument
Table
The instrument table contains 128 different instruments. Different MIDI
devices have different instruments in their instrument table. With such a
variety of instruments, you can see why MIDI file created with one device
can sound different when it is played on another device.
laying Music Files
2H -
5