Art of Noise Gates
Well, the mix seems to be progressing nicely. Tracks
have been cleaned up, compression and EQ applied where
appropriate. Things are going nicely. Then Mr. Big
from the record company decides to come to the studio
and have a listen. "Great song" he shouts
while rocking his head out-of-time with the music.
"This is gonna be a smash hit." You nod
in silent agreement. "Only one thing wrong though"
wait for it… "There's not enough bottom!"
"Oh no… Who is this guy?" you're thinking.
Well let me tell you. Ultimately, he's the guy paying
your salary so smile and say "don't worry, my
noise gate can fix that". And this is how it's
First you will need something that can generate a
pure 50Hz sine wave - if you don't have an oscillator
then just about any synthesiser will do. Then record
that sine wave onto a spare track throughout the entire
length of the song (now you think I'm going crazy).
Once the sine wave has been recorded, insert our new
best friend (the noise gate) into that channel and
take a feed from the kick drum track into the side
chain input of the gate. Then set the gate's attack
to zero (fast), hold to about 20ms and release to
Now adjust the threshold until the kick drum triggers
the gate and you should hear short bursts of the sine
wave in perfect synchronisation with the kick. All
you need to do now is balance the sine wave with the
This is a trick commonly used by dance producers to
get a fat, heavy kick sound that hits you in the chest
when you're on the dance floor. You will probably
have to make a lot of fine adjustments to the gate's
envelope before it sounds right, but Mr. Big will
be happy and you will be handsomely rewarded.
On further listening you notice a problem
with a certain rhythm guitar part. Four distorted
guitar tracks, all playing the same part and panned
extreme left and right. The sound is good and the
part fits nicely in the arrangement, but the playing
isn't tight. This is the part…
Some chords are played very
slightly early and some slightly late and this looseness
is spoiling the track. Well guess what. Our noise
gate can fix this. Don't believe me? Watch this.
First, route all of the rhythm guitar tracks into
a stereo sub group and insert another gate into this
Then create a MIDI part that matches the rhythm of
the guitar riff. It doesn't have to be the same notes,
as long as the rhythm is there, that's all we need.
Something like this will do.
Once you have created this MIDI part, assign an instrument
to it with a very percussive sound - a piano for example.
Then bounce it down to an audio file and import it
back into the song on a spare track. Name this track
At this point you can discard the MIDI part, as you
don't need it anymore.
Now send the audio from the
"gate trigger" track into the side chain
input of the gate on the guitar sub group.
Set the gate's attack to zero and set the hold and
release controls to fairly fast values. Then, hey
presto, the rhythm guitar part is amazingly tight.
Is that cool or what?
You will find that if you play around with the gate's
envelope and range controls you can make this effect
sound very extreme or very subtle.
Get in the groove
Another way gates can change the feel of a track is
when they're used to create accents in musical parts.
Here's an example.
Let's say there's a nice strummed, acoustic guitar
part playing with the rhythm section. It's quite tight
but lacking in dynamics. Just insert a gate on it
and side chain the snare track into it. This time
set the gate's "range" control to around
-3dB. Use a fairly quick envelope and what you should
hear is a 3dB increase in volume on the guitar part
every time the snare hits. As this is usually on the
back-beat (beats 2 and 4) this will very subtly push
the groove along quite nicely. It's something you
have to hear for yourself, so try it.
There's so many ways this simple, innocent tool can
enhance your mixing experience it's just amazing to
think about. Record producers have been making creative
use of noise gates since the seventies disco boom,
through the eighties - Madonna's Vogue, Seal's Crazy
- and right up to the current day. It's one of the
few tools that will never go out of fashion in this
very fickle industry. Once you start getting creative
with noise gates the ideas will just keep coming -
I haven't even mentioned trance gating yet, that's
probably worth another article. And finally, I was
going to call this article "101 uses for a noise
gate" but I was told to keep it short.
That's all for now.
ICOM installed a CA6 active PA system supplied by KME of Germany
in the Recital Hall.