About Equalization
The E62i, E31iand E30igive you fine control over shaping a sound, using a process called
equalization. But there are few areas of sound engineering more misunderstood than
equalization, and, just as good EQ can really help a sound, bad EQ can really hurt it, so
read on...
Every naturally occurring sound consists of a broad range of pitches, or frequencies,
combined together in a unique way. This blend is what gives every sound its distinctive
tonal color. The range of frequencies that can be heard by humans is sometimes called
ENGLISHthe audible range, and it includes frequencies from as low as 20 Hz (that is, 20 wavecycles
per second) to those as high as 20 kHz (that is, 20,000 wavecycles per second).
The E62iand E31iprovides a set of high-quality filters that divide the audible range into
31 1/3 octave frequency areas, centered at 20 Hz, 25 Hz, 31.5 Hz, 40 Hz, 50 Hz, 63 Hz,
80 Hz, 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz, 500 Hz, 630 Hz, 800 Hz,
1 kHz, 1.25 kHz, 1.6 kHz, 2 kHz, 2.5 kHz, 3.15 kHz, 4 kHz, 5 kHz, 6.3 kHz, 8 kHz, 10 kHz,
12.5 kHz, 16 kHz, and 20 kHz. The E30iuses the same high-quality filters, instead dividing
the audible range into 15 2/3 octave frequency areas, centered at 25 Hz, 40 Hz, 63 Hz,
100 Hz, 160 Hz, 250 Hz, 400 Hz, 630 Hz, 1 kHz, 1.6 kHz, 2.5 kHz, 4 kHz, 6.3 kHz, 10 kHz,
and 16 kHz. In all three models, OConstant Q� circuitry ensures that the bandwidth of each
of these frequency areas stays the same even when approaching maximum boost or
attenuation resulting in greatly reduced phase shifting and intermodulation distortion.
Each frequency area can be cut or boosted by as much as 12 dB, if the ?12 dB switch(es)
are on (in the down position). When the ?12 dB switch(es) are off (in the up position), each
of these frequency areas can be cut or boosted by as much as 6 dB, giving you finer
control and allowing you to construct gentler frequency curves.
If the Cut Only switch(es) on the front panel are off (in their up position), then when an
Equalizer slider is in its center detented O0� position, it is having no effect; when it is moved
up, the particular frequency area is being boosted; when it is moved down, the frequency
area is being attenuated (cut). However, if the Cut Only switch(es) on the front panel are
on (in their down position), then when an Equalizer slider is at its maximum (fully up)
position, it is having no effect; when it is moved down, the frequency area is being
attenuated (cut). In this circumstance, the center detented O0� position represents a cut of
-3 or -6 dB, depending upon the setting of the ?12 dB switch.
In most instances, the best way to approach equalization is to think in terms of which fre-
quency areas you need to attenuate, as opposed to which ones you need to boost (boost-
ing a frequency area also has the effect of boosting the overall signal; too much EQ boost
can actually cause overloadN with the accompanying Peak LED warning!). Be aware of the
phenomenon of masking, where loud sounds in one frequency range obscure softer
sounds in the same range; by cutting EQ Onotches� in a loud signal, you can actually make
room for a softer one to shine through. And try not to think of EQ as a miracle workerN no
amount of equalization can put a singer in tune or remove the distortion from an overload-
ed input signal! The key is to get the signal right in the first place, by using correct gain
structure and mic placement.
If you are using your E62i/ E31i/ E30ito equalize a complex mono or stereo signal (for
example, the master mix output of a mixing console), a more natural sound can be
obtained by setting up gentle Osmile� curves than by simply cutting or boosting individual
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