Behringer MX9000 - Manual (Page 33)

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9. EQUALIZATION
The variable parameters of the channel A and B equalizers on the EURODESK MX9000 are described in
sections 3.4 and 3.7.
Few people buying the EURODESK will need to be told how an equalizer works. But how to get the best out of
it? Well, that’s another story.
In the beginning EQ was an instrument for removing unwanted frequencies, or compensating for imperfect
microphone response curves, or bumps in a studio’s acoustic. It was a corrective device. Tamla Motown
turned that notion upside down in the sixties with the novel idea that you try to find for each instrument a
characteristic frequency not shared by the other instruments in the mix. Then you whack up it’s gain. This
makes individual voices punch through a mix in a slightly unnatural but exciting way. In general, corrective EQ
usually involves broadband (slope) contouring, together with narrowband notching of unwanted resonances.
The narrower the notch or “Q”, the less the total signal will be affected.
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Finding bad resonances is made easier by first frequency sweeping in boost mode.
“Motown” EQ is achieved by applying boost in a fairly broadband way. The broader the band, the more
musical but less instrument-specific the effect. Applying boost over a narrow bandwidth will sound “Honky”.
The two semi-parametric bands of the EURODESK EQ have had their Q fixed at 1, a typical and sensible
value. For sounds which require drastic corrective EQ (remember no MIDI instrument should need it), it is
advisable to have a couple of channels of fully comprehensive equalization in your rack. (You can always
bounce tracks though the outboard EQ, freeing up the unit for the next task). Check out our BEHRINGER
ULTRA-CURVE PRO DSP8024, which promises to be another price/performance buster.
The EURODESK EQ might be applied to a signal as follows: First, trim the LF and HF shelves to achieve the
required slope or “LOUDNESS”. (These controls mirror the tone controls of a typical HiFi amp.) Now use one
parametric band to boost the nicest frequency, and another to cut the nastiest. Over all channels in the mix, if
too many of the nicest frequencies coincide, then you might have to settle for second best in some cases!
Often you might want to boost two nice frequencies. Really nasty frequencies will need notching. Time to go
outboard.
Why does the upper mid bell frequency go up to 20 kHz? A more pertinent question might be, why has it
taken so long to get there? After all, even 16 bit (the lowest acceptable quality) digital audio sports a 20k
bandwidth: surely if 20k is important then so is controlling it. OK. You and I will never hear a pure 20k sine
tone. However, Rupert Neve, the audiophile Guru, would argue that when it comes to real instruments, what
happens even above 20k may have a perceptible effect on the listener. It seems that one reason why high-
quality (1/2" at 30 IPS) analog tape sounds better than DAT to many discerning ears is because, although it’s
frequency response begins to roll off at 12 dB/octave somewhere around 15 to 20 kHz, it is not abruptly cut
off at 20!
We have heard, or “detected”, a 20+ kHz low pass filter being switched in and out when monitoring an analog
master tape through a speaker system that included piezo-electric tweeter elements capable of reproducing
up to 40 kHz. Perhaps less controversially it can be shown that if cut/boost is applied at 20 kHz, a significant
portion of the resulting EQ curve for all but the tightest of Q’s actually occurs in the audible spectrum, below
16 to 18 kHz. For example if the BEHRINGER EQ is boosted by +15 dB at 20 kHz, the amount of boost at
10 kHz will be 3 dB. The resulting EQ curve will bear no relation to one where 3 dB of boost is applied at 10
kHz.
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A good vocal signal can be enhanced by applying a significant boost in the 15 k region or
higher, above the nasty sibilance region. Especially effective if you’ve got a de-esser post EQ.
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Use the LF cut to tighten up channels in a mix: maybe remove it only for the bass, kick drum,
toms, tablas, didgeridu and other deliberate subsonics. (When recording classical music ignore
this advice).
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With an LF cut at 100 Hz and a lo sheelf boost at 80 to 160 Hz, you have pretty much got a peak
response rather than shelving at the bottom.