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ADDENDUM
EQ Sweep Control
Although frequency sweep controls have graced the channel-EQs of recording mixers for
many years, they are only found on the more upscale P.A. mixers. As a result many P.A.
users, even veterans, are unfamiliar with their function. The Sweep control determines the
range of frequencies that are affected by the Mid cut/boost. It moves or sweeps the Mid
control's peak or notch in response up to several thousand Hertz or down to below 100
Hz. As a result it can have quite a noticeable effect on the sound, especially since the
MID cut or boost will be interacting with whatever cuts or boosts you may have set with
the Low or High EQ controls.
For example, if you have set a Low boost, a Mid boost swept all the way down to the
lowest frequency setting will alter the sound of lows and increase their volume. Be care-
ful this doesn't damage your woofers. And watch out for your tweeters/horns if you sweep
the boost up to the higher settings while the High EQ is boosted.
Considering that the Sweep control can alter everything you are accustomed to an
EQ doing, it would be worthwhile to spend some time becoming acquainted with how it
works. As music plays through a channel on the mixer and speakers, adjust that channel's
Mid, first for a boost then for a cut and Sweep them back and forth. (If there is no Mid
cut or boost setting, i.e. if it is set at the centre position, the Sweep will have no effect
at all). Now repeat the process with that channel's Low and High EQ controls at various
settings (but with the volume at a safe level for the speakers).
Hint: The PowerMAX Sweep has a "home base" setting marked with a triangle at the
2.5 kHz mark. This approximately corresponds to the setting of the fixed mid controls on
our other mixers. Set channels not requiring Sweep equalization at 2.5 kHz and the Mid
cuts or boosts will have more standard results.
Together, Mid and Sweep controls can be used to accomplish a variety of tasks from
combating feedback to improving the way things sound through the P.A. or on recording.
Here are some of those tasks and settings:
Note: These are approximate settings only. Use them as a starting point and "tune
around" them.
• Killing feedback? Set Mid at -6 dB and slowly rotate Sweep until the feedback stops.
If needed cut the MID further.
• Bonky sounding snare drum? -6 dB @ 200 Hz (roll off Low EQ -6 dB)
• Boomy bass drum? -6 dB @ 300 Hz (Low EQ @ +6 dB and High EQ @ +3 dB)
• Fwashy sounding cymbals? -9 dB @ 300 Hz (roll off Low EQ -15 dB)
• Excessive hiss from guitar, bass or keyboard amp? +3 dB @ 5 kHz (High EQ rolled off
-9 dB)
• Fading vocal range (notes too low for singer)? +3 dB @ 80 Hz (Low EQ rolled off -6
dB)
• Puffing on harmonica mic? -9 dB @ 80Hz (Low EQ rolled off -12 dB)
• Rack Toms? -3 dB @ 400 Hz
• Floor tom? -6 dB @ 200 Hz Generally speaking, you will probably end up with the
Mid in cut mode for most problem solving uses of the Sweep control. In any case you
will learn to use this feature judiciously. The best P.A. EQ setting is the one with the
least adjustment, but when you need to solve a problem it's good to know how to use
the tools.
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