By Julian Colbeck
Noise
When you hear the words ‘gate effects’ or ‘gates,’
what people are talking about - even if they don’t know
they’re talking about it - is a noise gate.
A noise gate is a piece of studio equipment whose primary
purpose, you won’t be too shocked to discover, given
its name, is to remove unwanted noise from a piece of audio
material. It’s an electronic switch that mutes a signal
falling below a certain level to ‘gate out’ unwanted
noise.
Say you have a nice recording of an acoustic guitar, but,
in the background there’s some noise (squeaks, the player
shuffling around a bit...). Well, you can apply a noise gate
to the track, and set the threshold at a level that when the
main signal (i.e. the guitar playing) drops below a certain
level the gate slams shut. Bingo. You won’t hear any
of that unwanted background noise in the gaps between your
guitar playing.
Effects
Aside from other controls for altering sensitivity, envelope
etc, noise gates can be used for other purposes like gluing
a sloppy bass part to a kick drum, or gluing a sine wave oscillator
to an 808 kick to generate deep bass. Noise gates can also
be used as effects generators using the so-named side-chain
feature.
Instead of the threshold being set manually, this cunning
feature ‘opens’ and ‘closes’ the gate
automatically depending upon another audio signal that’s
been patched into the side-chain input. If that audio signal
is something like drum machine pattern (i.e. lots of short,
dynamic bursts of signal) then that rhythm will be applied
to the main audio track on which you are using the noise gate.
In place of your acoustic guitar, let’s take a synth
pad, or some backing vocal ‘Oohs.’ If you apply
a noise gate with side-chain inputted drum beat on this type
of sound - i.e. a smooth, sustained audio signal - it’ll
turn it into a sort of groovy, stuttering effect in the exact
same rhythm as the drum beat. In effect the drum beat will
‘play’ the synth or vocal.
This effect is extremely infectious, creating instant danceability,
instant feel, instant but non-intrusive movement, not the
least because it is precisely in-time with the drum beat,
and so, we hope, with the rest of your track.
Style
Producers have been using this trick for years; ever since
the disco boom in the mid seventies. The great thing about
a gate effect is that it doesn’t impose a stylistic
slant on a track. It can be a subtle addition, working like
an occasional timed delay as on Madonna’s Vogue, or
it can be an intrinsic scene-setter as in the opening of Seal’s
Crazy. It can generate swing on a hard rock song, or be the
basis for an entire trance set.
However, using a ‘real’ noise gate isn’t
exactly problem free for those of us on a less than spectacular
studio budget. First you have to buy a noise gate or noise
gate plug-in. Then you’ve got to be able to understand
and operate these fairly sensitive pieces of equipment.
If you tie up your noise gate for a gate effect then you
won’t
be able to use it as, well, a genuine noise gate (you’ll
have to record one of the effects first, then unplug, replug
etc.) And as for plug-ins, DSP is always going to be an
issue in terms of the potential draw on your processor.
MIDI
So in 1994, shortly after the first Twiddly.Bits disk rolled
out of production, Keyfax Software came up with the idea of
creating a MIDI gate effect disk, which was inexpensive, a
cinch to set up, and enabled people to use multiple/simultaneous
gates. Needless to say it was an instant success and remains
in production to this day.
MIDI is tailor made for this type of purpose. Essentially
a noise gate either lets a signal pass (Full on=127) or shuts
it off completely (Off=0). By creating rhythmic patterns using
lots of 127 and 0 value volume control messages, you can so
replicate the exact same effect as does a side-chain/drum
machine-connected noise gate.
Moreover you can get more sophisticated by ‘half opening’
the gate (volume value of 34 or 64), plus you can apply the
rhythms to modulation, pan, filter controllers. Or you can
create massively complex effects by combining two or more
gate patterns to the same sound, or using the same gate pattern
on five different sounds. The possibilities are completely
endless.
Keyfax’ s Gate FX
This product, which can be downloaded from www.keyfax.com
or purchased on disk, comprises a series of 4-bar tracks within
a SMF .mid file. Each track contains different controller
data and so produced a different gate effect. Using MIDI gates
is as simple as using the same playback MIDI channel for both
gate effect and part (again, sustained synth pads and vocal
sounds work best). You can then simply copy and paste the
gate for as long as you want the effect to continue.... 100
bars, 16 bars, for 1 bar every 4 bars, even cutting and pasting
between different gates to produce completely new patterns....
it’s entirely flexible.
Opening the gates
Several other companies now produce MIDI gates. It is also,
to be fair, not that difficult to create your own patterns
without having to spend any money at all. Gate FX is simply
a great starting off point to see how it’s done.
In 2002 Keyfax revamped its popular Gate FX disk for the
Yamaha Motif, producing Mo’Gates in native Motif Pattern
format, building on the original disk with additional filter
and ‘bass tweak’ patterns. Gate FX has now been
re-launched as Gate FX 2002, containing the new beats and
effects created for Mo’Gates in regular SMF .mid format.
The original Gate FX collection used MIDI Controller # 7
(Volume) as the vehicle for delivering on/off messages. But
in fact Controller # 11 (Expression) can be a more sophisticated
option, allowing you to set a basic level using Volume and
controlling the internal fluctuations with Expression. Both
Mo’Gates and Gate FX 2002 now offer all their patterns
in a choice of Volume or Expression controllers.
Click
here for more information about Gate FX 2002. |
