Equalizer is probably the single most important tool in sound
shaping, and most sound engineers probably would choose it, if it
would have to be their only used processor. With the help of
equalizer we can match tracks together, make different instruments
sound in more uniform way, correct tonal balance between low, middle
and high frequencies and shape the whole recording in such a way,
that it starts to sound polished, natural and perfect.
Equalizer - The Study of Action
More
about equalizers and their practical application in the mix
How to use the Equalizer?
Parametric, graphic, paragraphic, the "Q" and
low-hi-pass\shelf\bell. What does it mean and how to use it
in my song?
For those who want more detailed, technical knowledge
on the use of equalizers in the mix here are some little
secrets and terminology from the studio kitchen. After applying
them to your mix it will be much better. At the
beginning let's get familiar with the technical jargon used
in equalizers. A typical parametric equalizer has the
ability to choose the 3 parameters for each of its filters.
They are:
-FREQUENCY - frequency [Hz]
-GAIN
- raises or weakens certain frequencies in sound [db]
-"Q" - otherwise called wideness of filter,
defines the field of action of a filter
While the frequency and gain values of the
equalizer
do not require a major comment, the value of "Q"
should be discussed here more in detail. This is a very
important parameter influencing the sound of any equalizer
very much. "Q" is determining how widely the
frequencies surrounding the center, set frequency will be
affected (boosted\weakened) by the gain parameter. Along with the desired frequency,
some surrounding frequencies are affected and the "Q" sets
how much of them are to be affected. Otherwise, you can say
that this is the boldness of action filter.
The two following pictures show you clearly
what is the difference between the wide "Q" and the narrow
"Q":
The frequency of 1000 Hz = 1 kHz was boosted here by 5
decibels. We see, however, that the value of Q = 2.9.
The equalizer's filter begins "kicking in" from about 400 HZ
and ends it's action about 2500Hz. You can therefore
say that it operates quite broadly. Let's look at the picture
below:
Here
the equalizer filter is also boosted by 5 decibels at 1000 Hz,
but the value of "Q" is 12.6. You can easily notice that the
frequency 1000 Hz is boosted only with a very small degree
of the neighboring frequencies, and it is from some 750 Hz
to about 1300 Hz. What practical difference does it
give when it comes to mixing the music? In the first case of
the wide "Q" accentuates the
whole main middle bandwidth. It will give a warm, broad sound,
and the volume of a track will be quite considerably
increased, which would require to turn it down a little in
volume.
In the second case, however, with a narrow "Q" the
track will not change in volume more than a hint, and
the frequency of 1000 Hz is boosted very selectively, so it will
not have such a large effect on sound, as in the first
instance. Yet we should add here that this type of filter (or
rather its shape), which was used in those 2 examples is called
"Bell Filter", because it recalls the shape of a bell. There
are other types of filters, which are described below.
When to use a narrow band "O", and when the wide "Q"? Generally, it is
understood that a broad "Q" gives a more natural sound. It
should therefore be used where we do not want to alter
the nature of the track too drastically, although obviously
too rigid rules are not the case here. Narrow "Q" is
often used to get rid of some unnecessary frequencies,
badly affecting the sound
or even to cut out a hi frequency noise in the vicinity of 10 000
Hz, or low "brooming" within the limits of 60 Hz. This
is more surgical type of application.
Personally, we recommend applying the broader "Q" in all cases
except the need of specialized approach to the sound problems,
which is a precise, almost surgical interference in the
spectrum. You should be careful here, because the deep cut
in the track with narrow "Q" can cause the instrument tracks,
voice or other sound very unnatural. In a broad variety of techno music
styles
this is a very common treatment and it is often deliberately used to
make the equalizer as a type of FX and achieve
extraordinary, shocking sounds.
Decibels
How many
decibels is much, and how many is moderate? Crisp, decisive
effect in audio spectrum change begins to be heard from about 3 decibels. For
good material, excellently recorded tracks such changes are not necessary
and a small change
of simply about 0.5 - 1.5 decibels will do the trick of setting the optimal sound
of a track. Again, however, there are absolutely no
rules, unless the raise or cut should be applied in
order to achieve the intended effect. We had cases of
very well-known performers, whose mixes needed a raise
in
bass during mastering almost 20 decibels in order to lift the lost depth
and ensure that the mix sounded as good in terms
of the lows, as the best commercial recordings heard on the
radio. There is therefore the only rule in boosting or
cutting with equalizer-that you need to raise or cut as much as necessary
to achieve the intended effect, whether it is 2 or 15 db. And do not be afraid of
turning knobs of equalizer and looking for the
right sound. This is a really
powerful tool for shaping the sound, the importance of
it simply can not be overestimated. It is probably the
most important sound shaping tool.
The types of filters in
equalizers
A typical parametric equalizer has a
number of filters for a choice of the nature of
action. The most flexible here are especially
software equalizers, which capabilities have substantially exceeded
that of the hardware devices. Le's return to
our example. The following 4 pictures show the 4 other
types of filters, in addition to the main type
called the "bell". They are:
-high shelf
-low shelf
-high cut
-lowcut
Here's the High
Shelf filter. It works in such a way that everything above a
chosen frequency has a comprehensive raise, thus giving
shape resembling a shelf. The "Q" factor sets the steepness of
transition to the shelve here.
Here we
have a Low-Shelf. Everything that is below the desired
frequency will be lowered, the "Q" sets out the steepness of
the slope.
Hi Cut.
This type of filter cuts quite steeply all the frequencies,
which are above the desired frequency. The "Q" defines the
steepness of the cut.
Low Cut.
This type of filter cuts radically all the frequencies that
are below the desired frequency. The "Q" defines the steepness
of the cut.
And here is the appearance of a typical
graphic equalizer in the software version. There is no longer
the ability to set the frequency and "Q" of each filter.
The
whole frequency band is divided on the sliders with a fixed
value of the "Q" and each frequency is
adjusted only by the
value of gain, whether boost, or cut. Seting the sliders gives a
graphical picture of how the equalizer affects the spectrum:
Since the
equalizer like that has a lot of (28) ranges of bands
dividing the sound spectrum it can be used for a very
selective raise or cut, achieving the
same effect as a narrow "Q" parametric equalizer. You
can also arrange the position of sliders, respectively,
to achieve the same effect as using various filters,
parametric equalizer, that is, for example, "Hi Cut" or
"Bell". Setting shelves or low\hi pass is also
possible using this type of equalizer. It's advantage is
very clear graphic representation of what is going on
with the sound spectrum.
The software
equalizers are present on the market or in studios already for a long
time, their useability is in many respects higher than in
the case of physical, hardware devices. However many experts
still believe that the hardware ones are better. Why the
hardware should be better and what the legend of analog devices
is derived from? Equalizers of software type are certainly not worse than analog devices.
The best proof of it is that many very reputable studies use
them regularly. There are more accurate and handy in use,
they can save their settings for different uses. There are more
and more software equalizers, many of them can
imitate their analog counterparts to the high degree. It is
worth mentioning that there are such equalizers as the Blue Tubes
PEQ-2A for example which can
successfully emulate the famous Pullmans, and are capable of
simultaneously cut and raise the frequency selection, which gives
a very distinctive sound, used on many legendary recordings,
such as the legendary album "Paranoid" of Black Sabbath:
Blue Tubes- Pullman
software emulation
Another
excellent design of program equalizer is an outstanding
Master Q from the Polish
company PSP- Professional Sound Projects:
PSP- Professional
Sound Projects- Master
Q
Characterized by a very soft, full sound, the sound of this
application reflects
the sound of excellent analog equalizer.
At the end we would like to give you some very useful
advices in the practical application of equalizers in mixing
material.
1
At the very beginning of mixing or
mastering it should be taken into account how and using what
equipment-technique the material was recorded. If it was recorded directly to a
computer workstation DAW without the use of the good
sounding path to
shape the sound, you almost certainly will require fairly
drastic use of equalizers at the mixing stage. Soloed tracks will
sound great, but despite of their mighty and clear
sound when soloed, they will not want to sound good when
played together, many instruments
will be lost in the mix in spite of beautiful sound when
soloed, the volume raise will not help and the whole mix
will sound flat and
dull. Similarly, if you use tracks created with VST instruments and they
were rendered to zero, without the use of any processor,
analog or software, their tracks will require the use of
radical and skillful equalization. So do not expect your mix
will sound great when everything is done on zero EQ, because
it will not.
2
If the recorded material has passed
through
gently and musically sounding analog devices, such as
reel-to-reel tape decks or tube compressors shaping the sound
in very desirable way, which were used initially
in the studios, the tracks will no longer require such
a big equalizer intervention. Equalizer may still be needed, but the
sound will already shaped by smooth sounding devices so that it can be used
with much less
equalization.
3
During equalization of tracks you should always
bear in mind 2 things: What to do in order to lift the most
characteristic feature of a particular
instrument or voice, as well as how to contrast different
tracks with each other. Only the tracks that are somehow
contrasted will be heard good and will work nicely together
in the mix. The ear of a listener will always pick up the
smallest nuances in such contrasts.
4
Instead raising the volume of an instrument, which is
barely audible in the mix, try to find a certain frequency, which is characteristic for
that instrument and boost it using equalizer. For example,
kick drums do not have to occupy at
all bass frequency taking the energy from another
instruments, you can take advantage of the equalizer and
shape it using two bands with a
fairly narrow "Q", one in the bass area and
another around 1000 Hz or even higher (find it), often even
a small change of 2-3 db
will greatly improve the audibility of the kick drum and
make a very noticeable improvement in mix.
5
You should think of the mix as a giant
puzzle. The tracks should be shaped to fit together. So, if you add some,
say,
1.500 Hz one one track maybe it would sound better to
remove the same frequency from another. It is worth
experimenting and trying, because it helps to make the
mix to glue together and sound as one piece. This leads to the
better sounding tracks that are not mutually
extinguishing their frequencies, but cooperate together as well
adjusted mechanism. Thus, every instrument
should occupy its own place in the mix.
Equalization is
one of the four methods used by engineers in the mix to
improve the sound of the tracks. The other three are the
stereo panorama placement, the volume and delay\acceleration of timing
of the track in order to make it more distinguishable and
thereby change the spectral characteristics in relation
to the frequencies
of other tracks. And yes, there is a fifth method of
changing sound- the dynamics devices like the
compressor
and expander. This is also loved by
engineers all around the world ;-).
6
Kick drum and bass are two instruments
that make up the spectral-rhythmic foundation of the sound. It
should be noted that they need to be set at frequencies with which they
complement each other, rather than competing. It is not good
to raise
the same frequency either for the bass and the kick in the
area of, for example, 80 Hz. Much better is
to make the bass more punchy at 120 db, and the kick more
deep at 80 Hz, or vice versa.
Both instruments will sound excellent and working together
much better, while
at the same time they will be perfectly audible in the
mixdown. It is very important to do it at mixing stage,
because the mastering will not be able to fix the problem of
the bass extinguishing the kick.
In addition, you might experiment with a cut of a
lower middle of the sound spectrum. If we cut some bass in the
vicinity of 250 Hz, where it is the most "mud" for bass guitar
and actually many other instruments,
while we add the slightly higher frequencies, about, say, 1800
Hz, the bass will perfectly clarify itself up against the
kick. If you
apply it to, say, electric guitar track, you might cut
everything below 80 Hz using shelf filter, making the bass and
the kick having more gain for
themselves and giving even more space to the mix. There is a
few things more desirable in a mix then the bass and kick
nicely working together and complementing each other.
If we act similarly
with each instrument of our song, cutting them at some
frequencies, and adding others, we will be able to find a great
sounding effect of the tracks interlocking themselves in the
mix and making one beautiful piece of art.
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inquires about mastering please contact us at:
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