Rane GE 130 - Manual (Page 4)

Manual-4 103117
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OPERATING INSTRUCTIONS
Insuring the proper level of gain though the GE 130 is
just as important as adjusting the equalizer bands. Improper
gain distribution is a common cause of loss of system
headroom and less than optimum noise performance.
The OVERLOAD LED informs of an imminent or passed
overload to the equalizer. Occasional blinking of the OL with
program source material is fine, indicating optimized signal-
to-noise performance of the GE 130. Run the GE 130 with an
input signal that is as hot as possible without the OL lighting
more than occasionally.
The BYPASS switch allows comparison of equalized
versus un-equalized signal. It is also useful in adjusting the
level of the GE 130 for unity gain and best signal-to-noise
performance. The gain of the GE 130 is optimized when there
is no sound level difference between the bypassed and the
active positions.
The overall gain range of the level control for the GE 130
is off to +6 dB for unbalanced operation, or off to +12 dB for
balanced operation. The level difference between the equal-
izer in bypass or active can be significant. Adjust the LEVEL
control so the signal level is the same between the bypassed
and active positions of the BYPASS switch.
GETTING STARTED
Here is one method of setting your equalizer that works
well. Begin with the following settings:
1. Engage the BYPASS switch. (switch depressed, BYPASS
LED on.)
2. Put all sliders in their center position (0 dB). The center
position has a grounded detent.
3. Position the CHANNEL LEVEL controls about “6” for
unbalanced operation and “7” for balanced operation.
4. Apply a signal to the system.
5. Verify the OL LED is not on—occasionally blinking
during extreme peaks indicates an optimal setting. But if it
lights up a lot or lights steadily, lower the output level of
the previous device in the signal chain.
6. Release the BYPASS switch and begin adjusting the
equalizer filters.
7. During filter band adjustments, if the OL LED lights more
than occasionally, turn down the output of the previous
device in the signal chain.
8. Once all filter bands are adjusted to your liking, compare
the signal loudness with the equalizer bypassed and active.
Adjust the CHANNEL LEVEL controls on the GE 130 so
there is no difference between the levels of bypassed
versus active.
9. The last step is to reconfirm that the OL LED lights only
when there are large signal spikes in the program material,
as in step 5 above.
For insight into how to use an equalizer, to alleviate
acoustic problems or to adjust the overall tone of the program
material, please read the following two sections.
ACOUSTIC COMPENSATION
A graphic equalizer may be used to correct many acoustic
problems. However, one should fully understand the ramifica-
tions of doing so. Acoustic problems are generally not
consistent across the entire area of sound coverage. This is
much more of a problem when setting up a sound system for
large venues. In a typical large room or hall, there will be
areas that have acoustic reinforcement problems and other
areas where certain frequencies are almost entirely canceled
out. Try to seek an acoustic remedy for acoustic problems
whenever possible. When this is not possible or feasible, an
equalizer may be used to compensate for an acoustic prob-
lem. But the problem is only improved at the point where the
measurement is taken, other locations in the room may be
adversely affected by the equalizer setting. For this reason,
measure the acoustic response of the system from several
locations and average the equalizer’s setting. Doing this
helps most locations in the venue to have an equal sound
quality.
The best way to “see” what the acoustic signature of the
room is doing to sound is to use a real time analyzer or any of
the many computerized measurement systems. Using these
devices to analyze the response of the room and the sound
system is the only accurate means available for setting an
equalizer properly.
Equalization can be like spice in the hands of a master
chef. A little goes a long way in improving sound quality, too
much and the mix is spoiled. If modest amounts of equaliza-
tion (6-8 dB) do not solve the problem, it is best remedied by
other means. Avoid adding large amounts of boost below 63
Hz, especially when using vented bass cabinets. Boosting
frequencies below the vented enclosure’s low frequency
cutoff can easily cause over excursion of the speaker’s cone,
causing premature failure. In addition, boosting low frequen-
cies can make your power amplifier run hotter, leading to
premature amplifier failure.
When equalizer adjustment is completed, compare the
unequalized sound with the equalized sound by alternately
engaging the BYPASS switch. Use familiar source material
and walk around in the sound coverage area to insure that no
anomalies have been introduced into the sound system. If it
sounds good, you’re done.
TONE CONTOURING
If a GE 130 is used for tone contouring by ear, be careful
about adding upper bass (63 Hz to 200 Hz) as this can cause
“muddiness” or loss of definition. (Also see the previous
warning about boosting frequencies below 63 Hz.) Middle
frequency problems usually express themselves by vocals
having a nasal quality (too much mid band boost) or vocals
not being easily understandable (usually caused by mid band
frequencies being under represented in the overall sound).
High band problems show as “sizzle”— not good, and is
sometimes caused by too much high frequency boosting.
This is most obvious with cymbals and hi-hats. To use the
cooking metaphor, high frequencies should simmer, not
sizzle.