Manual-4
SEQ 30L CONNECTION
Exactly where you install your SEQ 30L 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.
WHAT AND WHY
Tone contouring is accomplished primarily by ear. This
you know how to do. Be careful though, not to boost too
much bass. Be aware that the SEQ 30L 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 SEQ 30L 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, such as the
Rane RA 30. 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 crossover. Here are a few general
guidelines to decide where to install the EQ in the system.
Downstream of the Compressor
Since system EQ is aimed at controlling acoustic prob-
lems, install it after any compressor, which is designed to
operate on electrical signal. 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.
After any System Gain
The best configuration is: mixer, compressor/limiter,
equalizer, crossover, then power amplifier. Whenever
headroom allows, try to take all the gain at the mixer, and run
unity levels from then on. This also gives better noise
performance through the system. Connect the SEQ 30L
before the amplifier or active crossover. Take any required
line gain before the SEQ 30L. Avoid taking a lot of gain in
the crossover or power amps as this may create noise prob-
lems. The SEQ 30L 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 BY-
PASS. For details, read “Setting Sound System Level Con-
trols” available from the Rane website.
Send/Receive Loops
Mixers, mixer/preamps and the like often provide send/
receive loops for additional effects or EQ, and the SEQ 30L
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 SEQ 30L 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.
Because of this, the overall EQ adjustment process is signifi-
cantly easier and more effective.
Equalizing a sound system by ear is very difficult 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, unfortu-
nately 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.
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,
the type of music and your audience. Fatten the bass, sweeten
the highs, brighten the mids. Since you are starting from a
“tuned” system, your ear will not be fooled into thinking bass
is too high when actually mids are too low, or that highs are
too weak when really the mids are too strong.
Fact: analyzers don’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 for the program material. In fact, final opti-
mum EQ settings, made after analyzer testing, will vary
greatly depending on the type of music, sound pressure level,
size of the venue and disposition of the audience.
Conclusion: To consistently obtain the best sound from
your system, use an analyzer and then your ears, in that
order. The analyzer supplies the consistency and calibration
while your ears supply the good taste.
We of course recommend the very fine and affordable
Rane RA 30 Reatime Analyzer. Check it out.
All features & specifications subject to change without notice.107081
©Rane Corporation 10802 47th Ave. W., Mukilteo WA 98275-5098 USA TEL (425)355-6000 FAX (425)347-7757 WEB http://www.rane.com
