In a world obsessed with audio plug-ins, MIDI plug-ins may
not seem very sexy any more—but with MIDI’s continued vitality, they
remain very useful problem solvers. Let look at some ways in which this is the case.
Overview. Although processing MIDI data has
existed since at least the heyday of the Commodore-64, the modern MIDI
plug-in debuted when Cakewalk introduced the MFX open specification for
Windows MIDI plug-ins. Steinberg introduced a wrapper for MFX plug-ins,
and also developed a cross-platform VST format. MIDI plug-ins run the
gamut from helpful utilities that supplement a program like MOTU Digital
Performer to beat-twisting effects for Ableton Live. With Apple Logic
Pro X now adding Audio Units-based MIDI plug-ins, interest continues to
grow. Typically, MIDI plug-ins insert into MIDI tracks like audio
plug-ins insert into audio tracks, as in the Cakewalk Sonar browser at left.
Unfortunately most companies lock MIDI plug-ins to their
own programs. Therefore this article takes a general approach that
describes typical problems you can solve with MIDI plug-ins, but note
that not all programs have plug-ins that provide these functions, nor do
all hosts support MIDI plug-ins.
Instant quantization for faster songwriting. MIDI
plug-ins are generally real-time and non-destructive (some can work
offline as well). If you’re writing a song and craft a great drum groove
that suffers from shaky timing, don’t dig into the quantization menu
and start editing—insert a MIDI quantizing plug-in, set it for eighth-
or sixteenth-notes, and keep grooving. You can always do the “real”
Create harmonies and map drums. If your host
has a Transpose MIDI plug-in it might do a lot more than
audio transposition plug-ins can do—like transposing by intervals
or diatonically, changing scales in the process of transposing from one
key to another, or creating custom transposition maps that can map
notes to drums.
Filter data. You’re driving two instruments
from a MIDI controller, and want one to respond to sustain but not the
other . . . or filter out pitch bend before it gets to one of the
instruments. Data filtering plug-ins can implement these applications,
but many can also create splits and layers. If the plug-in can save
presets, you can instantly call up oft-used functions (such as removing
Re-map controllers. Feed a continuous pedal
through a remapping plug-in to control parameters such as modulation
wheel, volume, aftertouch, breath control, and the like. There may also
be an option to thin out or randomize control data, or map data to a
Process MIDI data dynamically. You can compress,
expand, and limit MIDI data (to low, high, or both values). For example,
a plug-in could specify that all values under a specified value adopt
that value, or compress velocity dynamics by a ratio such as 2 to 1.
While you don’t need a MIDI plug-in to do these functions (you
can usually scale velocities, then add or subtract a constant using
traditional MIDI processing functions), a plug-in is more convenient.
Go back to the ’80s. Although arpeggiation
isn’t as front-and-center in today’s music as it was when Duran Duran
was tearing up the charts, it’s still great for background fills and ear
candy. With MIDI plug-in arpeggiator options like multiple octaves,
different patterns, and rhythmic sync, arpeggiation is well worth
re-visiting if you haven’t done so lately.
Arpeggiators can also produce interesting patterns when fed into
Add the human touch. “Humanizer” plug-ins
randomize parameters, like start times and/or velocities, so the MIDI
timing isn’t quite so rigid. I think they’re more accurately called
“drunkenness simulators” because musicians tend not to create totally
random changes. Taking a cue from that, however, consider teaming
humanization with an event filter. For example if you have a string of
sixteenth-note hi-hat triggers, use an event filter to increase
velocities that fall on the first note of a beat, and perhaps add a
slight increase to the third sixteenth-note in each series of four. Then
if you humanize velocity slightly, you’ll have a part that combines
conscious change with an overlay of randomness.
Go beyond traditional echo. Compared to audio echo,
MIDI echo can be far more flexible. Much depends on a
plug-in’s individual capabilities, but many allow variations on the
echoes—e.g., transposing pitch as the notes echo or adding swing (try that
with your audio plug-in equivalent), and more. But if those options
aren’t present, there’s still DIY potential because you can render the
track with a MIDI plug-in, then tweak the echoes manually. MIDI echo
makes it particularly easy to generate staccato “dugga-dugga-dugga”
synth parts that provide rhythmic underpinnings to many dance tracks.
The only downside is that long, languid echoes with lots of repeats eat
up synth voices.
Experiment with feel. A Shift MIDI plug-in
shifts note start times forward or backward. This benefits greatly from
MIDI plug-ins’ real-time operation because you can listen to the changes
in “feel” as you move, for example, a snare hit ahead or behind the
Banish glitches. “De-glitcher” plug-ins
remove duplicate events that hit on the same beat, filter out notes
below a specific duration or velocity, “de-flam” notes to move the start
times of multiple out-of-sync notes to the average start time, and
perform other tasks that help clean pollution from MIDI data streams.
Nuke “wrong” notes. Plug-ins that can snap-to-scale
pull errant notes into a defined scale—just bash away at a keyboard (or
have a cat walk across it), and there won’t be any “wrong” notes.
Placing this after a randomizer can be very interesting, as it offers
the benefits of randomness yet notes are always constrained to
Analyze chords. Put this plug-in on a track, and it
will read out the kind of chord made by the track’s notes. With
ambiguous chords, the analyzer may display all the voicings it
recognizes. Aside from figuring out exactly what you played when you had
a spurt of inspiration, for those using MIDI backing tracks an analyzer
simplifies figuring out chord progressions.
Apply an LFO to just about anything. Being able to
change MIDI parameters rhythmically can add considerable interest and
animation to synth modules and MIDI-controllable signal processors.
Although some DAWs let you draw periodic waveforms into an automation
lane, a Continuous Controller generator provides these same functions in
a much more convenient package.
The above functions are fairly common—but scratch beneath
the surface, and you’ll find all kinds of interesting MIDI plug-ins,
either bundled with hosts or available from third parties. Happy data