YORKVILLE AP812 Manuel De L'utilisateur page 16

14
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 PA mixers. As a
result many PA users, even veterans, are unfamiliar with their function. The
SWEEP control determines what range of frequencies is affected by the MID
cut/boost. It moves or sweeps the MID control's peak or notch in response all
the way up to several thousand Hertz or down to below 100Hz. 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 the lows and increase their volume. Be careful 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 HI 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 center 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 2.5kHz
mark. This approximately corresponds to the setting of the fixed mid controls on our other
mixers. Set channels not requiring SWEEP equalization at 2.5kHz 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 PA or on recording. Here are some of those tasks & settings:
Note: These are approximate settings only. Use them as a starting point and tune around them.
• Killing feedback? Set MID at -6dB and slowly rotate SWEEP until the feedback stops. If
needed cut the MID further.
•
Bonky sounding snare drum? -6dB @ 200Hz (roll off LOW EQ -6dB)
•
Boomy bass drum? -6dB @ 300Hz (LOW EQ @ +6dB & HIGH EQ @ +3dB)
•
Fwashy sounding cymbals? -9dB @ 300Hz (roll off LOW EQ -15dB)
•
Excessive hiss from guitar, bass or keyboard amp? +3dB @ 5kHz (HI EQ rolled off -9dB)
• Fading vocal range (notes too low for singer)? +3dB @ 80Hz (LOW EQ rolled off -6dB)
• Puffing on harmonica mic? -9dB @ 80Hz (LOW EQ rolled off -12dB)
• Rack Toms? -3dB @400 Hz
•
Floor tom? -6dB @ 200Hz
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 PA 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.
EQ MID SWEEP Addendum 01.06.28.99