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Manual-4

MQ 302L CONNECTION

Exactly 

where

 you install your MQ 302L into a sound

system significantly affects such things as noise, system
headroom, compressor/limiter performance and other factors
influencing overall sound quality. Both 

what 

and

 why 

you are

equalizing determines 

where 

you install it. We’ll leave the

when

 and 

who

 entirely up to you.

WHAT AND WHY

Tone contouring is accomplished mainly by ear. This you

know how to do. Be careful though, not to introduce too
much boost to the bass area. Be aware that the MQ 302L is
capable of boosting signals up to 12 dB (4 times as large!)—a
level at which great care should be taken to prevent seismic
disturbances. Optimal gain setting is indicated by the +4 dBu
indicator lighting occasionally, while the OL indicator does
not light.

The MQ 302L can be used to align crossovers and flatten

speaker response. The best way to “see” what your sound
system is doing, is to use a realtime analyzer. A 1/3-octave
realtime analyzer is an accurate means for setting a 1/3-octave
equalizer properly.

WHERE

For tone contouring, the equalizer may be used at any

point in the signal chain, such as insert loops in a mixer to
equalize a single instrument, sweeten a tape recording, etc.
When an equalizer is used for acoustical correction, the
equalizer should be one of the 

last

 pieces of gear in front of

the amplifiers and active crossovers. Here are a few 

general

guidelines useful in deciding exactly where to install the MQ
302L in the system. See Figure 1 on the next page.

Downstream of the Compressor

Since system EQ is aimed at controlling 

acoustical

problems, install it 

after

 any compressor, which is designed to

operate on electrical program material. For one thing, the
equalizer slider settings will change in each room location,
which in turn affects the control voltage and threshold
responses of the compressor, rendering it inconsistent.
Secondly, large amounts of boost often cause tone differences
by causing some frequencies to limit or compress before
others.

Upstream of the Limiter

If a limiter is installed strictly to protect the drivers, then

install the limiter just before the power amplifiers. A good
limiter leaves the dynamics unchanged until the amplifier
reaches driver overload levels.

After any System Gain

The best configuration is: mixer, compressor/limiter,

equalizer, active crossover and power amplifier. Whenever
headroom  allows, try to take all the gain at the mixer, and run
unity levels from there on. This also gives better noise
performance from the mixer. Connect the MQ 302L before
the amplifier or active crossover. Take any required line gain
before the MQ 302L. Avoid taking a lot of gain in the

crossover or power amps as this may create noise problems.
The MQ 302L operates at unity gain with the INPUT LEVEL
control at the 0 dB center detent when sliders average to
center (0 dB). You can test this with the EQ BYPASS
switch—adjust the INPUT LEVEL control so that volume
does not change when switching between ACTIVE and
BYPASS. For more information, read RaneNote 135, “Setting
Sound System Level Controls,” available from the factory or
the Rane website.

Send/Receive Loops

Mixers, mixer/preamps and the like often provide send/

receive loops for additional effects or EQ, and the MQ 302L
works well in this situation. Just be sure to keep input trim or
gain controls turned up as far as the mixer input headroom
will allow, to avoid taking excessive gain downstream and
creating noise problems.

OPERATING INSTRUCTIONS

The MQ 302L is an accurate, professional quality instru-

ment capable of precise equalization down to a fraction of a
dB. You can expect several advantages from your constant-Q
equalizer over conventional designs: Moving one slider will
not affect neighboring filters as much, so you won’t spend
time re-adjusting sliders (we call this “equalizing the equal-
izer”). You’ll be able to obtain better feedback control
without losing sound quality. All sliders maintain smooth,
consistent and accurate calibrated control over filter levels,
which is especially critical in low-profile equalizer designs.
Because of this, the overall EQ adjustment process is signifi-
cantly easier and more effective.

Equalizing a sound system by ear is a 

very

 difficult

process to achieve successfully, especially in a timely
manner. Although the human ear is very sensitive, it is 

not

calibrated, nor consistent, and frankly the odds 

against 

a well

behaved, clear sound system are very great when tuned by
ear. Most people know when a sound system doesn’t sound
good, unfortunately they just can’t tell exactly 

why

 and 

where

it’s not right. 

Because of this, we strongly recommend the

use of a realtime analyzer to properly equalize your system
with the MQ 302L.

Forget everything you’ve thought about analyzers and

consider this: there’s a newer generation of analyzers which
are compact, simple, very easy to operate and surprisingly
affordable. Best of all, they can make a drastic improvement
in the overall performance of your sound system while saving
a great deal of time and effort.

A realtime analyzer helps you quickly achieve things

nearly impossible by ear: flatten speaker response, minimize
feedback, reduce room resonance and achieve accurate
crossover alignment. In most cases, simply “normalizing” or
“flattening” a sound system is a surprisingly drastic improve-
ment, but 

don’t stop there

:

Remember this Rane proverb: “Look, don’t stop, and

listen.” Once you have aligned the system by 

looking 

at the

analyzer, 

don’t stop 

at this point. 

Listen 

to the music

program and make additional adjustments to suit your taste,

Summary of Contents for MQ 302L

Page 1: ...s center detent 0 dB Try to make more cuts than boosts After equalizing use the EQ switch to compare equalized and non equalized signal While EQ is switched to ACTIVE out adjust the INPUT LEVEL to the...

Page 2: ...and AES ANSI standards XLR wiring convention is pin 2 Positive hot pin 3 Negative cold and pin 1 Signal ground for unbalanced use Pin 1 and the connector case or shell are tied to chassis ground INPUT...

Page 3: ...TS jacks Using both types of Outputs are permissible to drive two devices such as an amplifier and a recorder LEFT RIGHT INPUTS Choose between the balanced XLR or the balanced unbalanced TRS jacks bu...

Page 4: ...er amps as this may create noise problems The MQ 302L operates at unity gain with the INPUT LEVEL control at the 0 dB center detent when sliders average to center 0 dB You can test this with the EQ BY...

Page 5: ...on t have good taste people do Analyzers consistently and accurately tell it like it is but ultimately personal judgment determines what sounds good or appropriate In fact final optimum EQ settings ma...

Page 6: ...ll or email the factory download it from Rane s web site http www rane com or ask your dealer for a copy Rane s policy is to accommodate rather than dictate However this document contains suggestions...

Page 7: ...Manual 7 VARIOUS XLR CABLE ASSEMBLIES...

Page 8: ...rm downward expander describes this type of applica tion ground Any electrical reference point for measuring voltage levels Usually a large conducting body such as the earth or an electric circuit con...

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