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Extreme EQ (part 1)


How do you get your excitement: Bungee jumping? Snow boarding? Beach volleyball? Or maybe Extreme EQ!

What goes through a mixing console designer’s mind when he starts work
on the EQ section. Is he thinking, “How can I give the engineer more power
and control?”, or is it more along the lines of, “I’d better
not give the engineer too much power and control – what might he do with it?”.
The more consoles I listen to, the more I am inclined to think the latter. OK,
it is important for an EQ section to be musical, and to allow very fine differentiation
in settings for when just subtle changes are required. But what do you do when
you want to rip a sound apart, tear out its entrails and shove the bleeding
mass in the face of the listener? If you’ll excuse my metaphor, you could
turn to an outboard EQ but I think you will find it still a little too polite.
In all probability these days an outboard EQ will just be part of a mixing console
channel taken out and put in a rack mounting box, although there are exceptions.
For Extreme EQ, we have to look outside the cozy world of what we consider to
be audio equipment into what is known to the trade as the MI – musical instrument
– market. Here we will find hardware and software that will go far beyond the
capabilities of most of the EQ units we would normally consider. Of course,
conventional EQ units can do lots of things that MI systems cannot, but we already
have lots of fine control, subtlety and musicality – we need raw power! I have
chosen examples of filters which I can guarantee will amaze you if you have
never heard anything but a conventional EQ before, one a traditional piece of
hardware with knobs and switches, the others being software plug-ins that run
with Steinberg’s Cubase VST.

Mutronics Mutator

The Mutator is basically a two channel low-pass filter, with LFOs to modulate
the cut-off frequency and envelope followers to allow the envelope characteristics
of one sound to be superimposed upon another. The filter really is the essence
of the Mutator. Basically all it is is the filter circuitry of a traditional
analogue synthesiser brought up to modern standards of noise and distortion
performance. As simple as that, and in fact you could think of Mutator as an
analogue synth without oscillators – just plug in your own sound source. It
is a low-pass filter meaning, as you already know, that high frequencies are
attenuated, in this case with a slope of 24dB/octave. In a 24dB/octave filter,
above the cut-off frequency, as the frequency doubles the output voltage is
reduced to a sixteenth. This is the first and major difference between this
and standard EQ. With conventional equalisers the slope will be a mere 12dB/octave
or 18dB/octave which reduces the levels of higher frequencies but still leaves
them audible. A slope of 24dB/octave chops them off with an axe. The result
is that you can input a signal with a fizzy irritating high end and reduce the
cut-off frequency to leave only the useful components. With a 24dB/octave filter
the result can still be sharp and incisive, whereas with a 12dB/octave or 18dB/octave
filter by the time you have eliminated the fizziness the sound will just be
dull. Another difference between the Mutator’s filter and the filter you
would find on a conventional EQ is that where the conventional designer would
only allow you to filter frequencies down to, say, 2kHz with a low-pass filter,
the Mutator goes all the way down to subjectively nothing at all – the cut-off
frequency is so low that the only signal left is a vague rumbling in the distance.
Don’t conventional EQ designers trust us?

David Mellor

Layout, Signal Flow & I/O

Layout, Signal Flow & I/O

This high level audio course is essential knowledge for anyone who wants to learn how analog consoles and their state of the art studios are "wired up." It gives you the deepest possible understanding of mixing console Signal Flow and I/O both analog & digital.

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David Mellor