Basic EQ Theory
To understand
EQ is to understand limits. It is in it's essence an understanding
that allows the whole (the song) to sound bigger by making the elements
(the tracks)
sound smaller, more narrow, and dare I say it in the world of
phattness, thinner.
This is because the audio bandwidth is itself limited. There is
only so much space
you have and if you fill it up with frequencies that overlap
and conflict, you will
not be able to hear the music through the sound. Stated
positively, if you carve
out a distinct sonic space for your instruments, you will
hear each more clearly.
That is the basic point and essential understanding that
goes into developing a
mix. Always remember, it is not how things sound in
isolation that matters, it's
how well they sound in the mix.
The
Audio Bandwidth=20Hz to 20kHz
 |
Like it or not,
this is all you have to work with as you put your song together. Every element
has to "fit" into this sonic space. Note the above example coming straight out
of Cubase with no processing. Its got an awesome low bass synth track from Atmosphere.
Look at that 30hz bump! Lets solo it and look in another display from Waves
(below).
As
you see there is low frequency energy extending way below what we can hear. This
energy will rob the song of audible bass and make speakers work very hard for something
that has no benefit. So lets fix it by applying a "bass rolloff"
With Waves Linear
phase Bass EQ we'll apply a rather steep resonant rolloff where the bass will
peak where I want it around 70 Hz and then get out of the way quick.
As
you see the result is dramatically conveyed in the screen. I've removed the bass
you can't hear and also cut a little bit of the "mud frequencies" around 250Hz.
There is only
one problem. It does not sound as good as it did. It is not as deep,
or powerful.
Mr. Newb,
who has finally recovered from his near-lobotomy shouts out.
"You should have left
it, Tweek, it sounded better before, you've turned a great
bass into a wimply thang."
Perhaps so, perhaps not. I still have to add a kick,
more deep synths, a ton of
drums and percussion and some vinyl brass hits.
The point is that I now have control
of the bass and i can move that peak from
75hz down to 60Hz anytime I want. I can
add a kick that extends lower and
peaks at 50HZ and you'll feel it. The bass patch
no longer controls the song and
where things have to go. Also we must keep in mind
that 50Hz is a very "boomy"
frequency that will make many speakers distort and ruin
the rest of the track.
While 50Hz sounds great on my Mackie 824's, I can guarantee
you it does not so
so tight on other speakers.
The Theory of Masking
Tweak reaches into his box of manuals he always carries
and pulls out a very scary looking Alien mask. You think the lobotomy thing was
bad, now you are in for it. The Pros in the back start pointing to their watches
and emit a sullen groan, "here he goes again"
The masked Tweak turns towards
the pros. "Alright you guys, get out!"
"But T-t-t-tweak, we were just
wondering how long this is going to go, c'mon man!"
"I said, get OUT!"
The pros start shifting around
and start looking at each other. I mean is he kidding or what!
When
one masks anything you can't tell what it really is and its the same with
audio. When you have 2 or more parts sharing the same sonic space you will only
hear the
loudest, the other sounds will weaken to the point where you can't really
tell what they are.
Some examples: A Bass that masks the kick will make a great
kick sound like its not there.
A full spectrum distorted guitar will make words incomprehensible. A bad vocal track will mask
a great sounding instrumental mix.
2 guitars using a similar tone will make a jangly mess and you
can't tell what either
is playing.
The keyboard
player starts scowling at the guitarist, who has just ripped off his shirt and put
his amp on volume 9. So the keyboard player puts his amp up to 10. Your vocalist
is getting all peeved because she can't hear herself now so she starts screaming
instead of singing and its o-my-god-awful. Now even the drummer can't hear himself
so he starts banging on the crash cymbal. Neighbors complain, police arrive and
you find out you are going to jail for some unpaid traffic ticket. That is masking
at work.
Making the Mix "Sit Right"
Waves Native Platinum Bundle (Macintosh and Windows) |
The solution to masking problems
usually involve a combination of 4 Possibilities.
1. Fix with panning. By moving
things left or right you can cure many masking problems. But not all. You can't
move the kick of bass or vocal too far from the center or the whole mix gets lopsided.
But you can move rhythm guitars, synths and percussion way off center and it helps.
2. Fix with EQ. Bass removal from
your tracks does wonders. At minimum put a low cut (high pass) filter on every track
except the kick and bass (which get their own more extensive treatment).
3. Fix by dropping one instrument
for part of the mix so both the mask and masked are not playing simultaneously.
4. Removing the track entirely.
Once you get your mix sitting right then you can
get to work on fattening it up by adding compression and maybe putting back some
of the frequencies you removed with EQ. The difference is now you have control over
your mix.
EQ Production Tips
OK, it's time to go out there.
Here's a few little production secrets, your reward for coming so far.
1. The Brain, Perception, and the Mystery of the Missing Fundamental
The "fundamental" is the loudest
part of any musical note. Remember that. See, every note made by any instrument
contains a fundamental and overtones (other frequencies). We identify pitch by the
fundamental, and identify the instrument by its unique series of harmonics (overtones,
other frequencies).
How many of us have heard a deep
hip hop groove where everyone is nodding their heads then suddenly the producer
drops a note. The sheer inertia in our brains keeps us on the beat and we replace
the missing beat in our heads. This is a cool effect. And it works on other instruments
too. One theory has it that you can almost totally remove the fundamental once it
has been established and only keep the overtones. Establish your groove then back
it off with automated EQ, giving other stuff a chance to breath. Come around to
a short section after the chorus and put it back.
2. Vocal "telephone" effects
One of my favorites for vocals. Use a parametric
EQ and cut away a big chunk of the low and lower mids. I usually go from zero
to 700-900 hz cut away. I will also roll off the high end sharply. This
just leaves the mids and upper mids. Squeeze those filters to shrink the bandwidth
of what you hear till its tasty. Best not to boost very much in the upper
mids; it gets harsh if you are not careful. This effect makes vocals more
intelligible while it shrinks their sonic space,
letting other instruments stay
on top as well. You can also get this effect with guitar
distortion and bit
crushing, if used lightly
3. Creating a worldly color.
Here you put an eq after a reverb and only let
a narrow bandwidth through, starting with lower mids and ending with upper mids.
Use in a very subtle way, just a shadow behind the drums or lead vocal. Use
a short "room" reverb.
4. Spacey vocal delay
At the last word of a verse or chorus, automate
a send to slam the vocal into a digital delay and let it run away with feedback
till it self-oscillates. Normally this would overtake and ruin the whole mix.
So put on a limiter and make sure the oscillation can only be heard at a low level,
no matter how out of control it gets. Now after the limiter put that telephone
eq or similar on the bus. In the end its sound like an ethereal reverb.
When you are done with the effect automate it to shut off or bypass.
5. Playing with resonant peaks.
Use a narrow parametric reverb that can sweep
the whole audio bandwidth. Extremely narrow "Q" factor. The slope of the eq curve
looks like a narrow pin. Now automate a sweep over some audio material.
You can make effects with your software parametrics that rival analog filters in
synthesizers. Use your automation tools to sweep up and down the audio bandwidth.
Good for trance like basslines. You can experiment with 2 bands going in opposite
directions, perhaps a wide band cut and an narrow band boost.
6. Bass Roll-off.
Its a good practice to try a roll off on every
track and don't be afraid to push the eq to cut off or roll off everything under
500hz. If it sounds "wrong" then gradually dial some bass back in till it
sounds right. The idea is to cut away as much as possible. This will
give you a solid low end for your kicks and bass. Tracks that may benefit from a
roll off are guitars and cymbals. There may be a gentle bass roll off applied to
the whole mix. But to minimize the need to do this, get rid of unwanted
bass at the track level.
7. Better definition on Electric Bass
Newbs tend to think if they boost the bass band of a bass it
will sound "more like a bass". However, boosting the bass band easily can
overpower the mix and make the bass sound indistinct at the same time. The
way out here is to leave the bass band alone or actually roll some of it off and
boost a region 4-5khz by a few db. By boosting the treble part of the bass
it makes the timbre more identifiable
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