MIDI Special Effects
MIDI technology, while not a substitute for a real
performance, can do quite a lot more than most give it credit for, if
the hardware and software allow for it. Roland sound modules (Yamaha
has different resets) allow adding reverberation and other features by
using system exclusive (sysex) messages but, in addition to these
messages, controller messages allows for changes in sound on these
modules. In addition, the "envelope" sounds of the patches themselves
may be changed manually on the module and then a "dump" may be sent to
the software before the file begins playing (space must be allowed for
the dump messages at the beginning and, often, ending of the file.).
This is apparently the way the quite realistic Pipe Organ Project files
are set up, though I don't know exactly how it's done.
It must be stressed that these SC POP files will either not
play at all or not play properly if the software and hardware is not
compatible.
Producing "special effects" in MIDI: The most vexing problem
seems to be harmonics, mostly but not entirely in string patches.
1. The chief means of producing a harmonic is to use the 7th
octave (where middle C is C4) especially at a low velocity. (download MIDI file)
1st example) and this may be transposed down an octave as well by using
the same notes plus pitchbend. (pointers CC101 and 100 at 0 and data
entry CC6 at 12 (the octave) and the maximum -8192 pitchbend. (2nd
example) The 3rd example, in the solo cello patch I've tried a
different approach from before. I've put the cello notes an octave
lower and used pitchbend to raise it to the desired octave. At the same
time, I've used the harmonics patch 32 and panned it to the same place
as the cello (+44). It works somewhat better than my previous attempt I
think, and is certainly more compatable. (download effects MIDI
file)
2. Muting: in strings anyway, I have found setting CC71
(harmonic content) to around 40 gives a pretty good muting effect.
(example 1) This may also work on other instruments and there is a
"mute trumpet" patch in the GM specifications. (#59 or 60.) But be
aware that there are different ways of muting a trumpet and sometimes
it would be more appropriate to use a regular trumpet patch with CC71
or other controller giving an entirely different tone color.
In all cases when any of these controllers are set to above
or below 64 (the default setting) they should later be returned to
default (which I've only done after the ponticello example).
3. The string effect "Sul ponticello" ("at the bridge") is
quite easy to do with the aformentioned CC71 and setting it at around
85 (depending on the patch) does the trick. In general, this device is
used mostly with a bowed tremolo and CC71 will work either with a
written-out tremolo or tremolo patch (example 2). "Sul tasto", "sulla
tastiera" or the French "sur la touche" all mean "over the fingerboard"
and may probably be done with the same controller 71 setting as muting,
described above. I haven't had occasion to use "col legno" ("with the
wood", i.e. the back of the bow.) so here I must plead ignorance. But
one MIDI file that deals with col legno uses the "shamisen" patch
(106 or 107) (A Japanese lute-like instrument) and it works pretty well
I think.
4. The horn (sometimes called "French horn") is a special
case in which the quality of the tone is controlled by velocity (though
volume, CC7, and expression, CC11 can control the loudness further.)
and care must be taken so that sudden high velocities don't give an
unwanted "brassy" (French "cuivré") effect. Other patches may react
similarly but the GM horn patch is unique. Used in a controlled manner,
the cuivré sound can be highly effective. (examples 3 and 4: Yes,
Siegfried with non-cuivré echo!)
5. The pizzicato: There is only one patch (45 or 46) in GM
and, at least the earlier, GS specs. The question has come up: How is a
difference made between a solo pizz. and that for an entire ensemble?
In most cases, it doesn't seem to matter much but, if a difference is
wanted, the chorus controller (CC93) may be employed. example 4 as
"solo" and 5 as "ensemble". Note that I have helped with the reverb
controller CC91 and copied the second pizz. example to another track,
moved the notes slightly and panned it to the opposite side from the
first track. It may not be necessary or even wise to do all of these
things in the context of a file and the panning difference may be made
much slighter, of course, but I wasn't trying to be subtle here.
Compatibility: Harmonics will work on most any setup but the
70-74 controllers are largely for a Roland sound module. (They may work
on a Yamaha and some newer soundcards to some extent.)
Edward Gold
