MACKIE ProFX4v2 - Manual (Page 13)

Owner’
s Manual
13
Owner’s Manual
Stereo Graphic EQ and Main Meters
23. Stereo Graphic EQ
This 5-band graphic equalizer adjusts the main
mix output. It affects the line-level outputs, but not
the headphones or tape outputs. This EQ may be used
for a monitor mix instead of the main mix if the main
mix/mon 1 switch is engaged. It may also be quickly
bypassed using the EQ in/bypass switch.
Each slider allows you to adjust the level of its
frequency band, with up to 15 dB of boost or cut,
and no change in level at the center (0 dB) position.
The frequency bands are: 80 Hz, 250 Hz, 800 Hz,
2.5 kHz and 8 kHz.
The EQ section comes before the main mix level
and meters. As with the channel EQ, just take it easy.
There is a large amount of adjustment, and if you
are not careful, you can upset the delicate balance
of nature. Although it may not seem cool to actually
turn down controls, with EQ it is often the best option.
Turn down the offending frequency range rather than
boosting the desired range. You may use it to reduce the
level of some frequency bands where feedback occurs.
24. Main Mix / Mon Switch
This switch allows you to choose if the stereo
graphic EQ is used for the stereo left and right main
mix or if it is used for monitors. For example, there
may be times when the graphic EQ may be used wisely
in the monitor mix to reduce feedback in the monitors
from nearby microphones.
25. EQ In / Bypass Switch
This switch allows you to quickly engage or
disengage the stereo graphic EQ. This may be used
for quick checks of your EQ settings, or to shorten
the signal path if you do not need to use the EQ.
26. Main Meters
These peak meters are made up of two columns
of twelve LEDs, with three colors to indicate different
ranges of signal level, traffic light style. They range
from –30 at the bottom, to 0 in the middle, to +20 (OL)
at the top.
When 0 dBu (0.775 V) is at the main left and right
TRS outputs, it shows as 0 dB on the meters.
You can get a good mix with peaks flashing anywhere
between –20 and +10 dB on the meters. Most amplifiers
clip at about +10 dBu, and some recorders aren’t so
forgiving either. For best real-world results, try to keep
your peaks between “0” and “+6.” Remember, audio
meters are just tools to help assure you that your levels
are “in the ballpark.” You don’t have to stare at them
(unless you want to).
21. Power LED
This LED will illuminate green when the mixer is
turned on, as a reminder of how on it really is. If it is
not on, then it is off, and the mixer becomes a rather
nice weight for keeping your morning newspaper from
blowing away in the wind.
If it does not turn on, make sure the AC adaptor is
correctly inserted at both ends, the local AC mains
supply is active, and the power switch is on.
22. 48V Phantom Power Switch
Most modern professional condenser mics require
48V phantom power, which lets the mixer send low-
current DC voltage to the mic’s electronics through the
same wires that carry audio. (Semi-pro condenser mics
often have batteries to accomplish the same thing.)
“Phantom” owes its name to an ability to be “unseen”
by dynamic mics (Shure SM57/SM58, for instance),
which don’t need external power and aren’t affected by
it anyway.
Press this switch in if your microphone requires
phantom power. (Always check the position of
this switch before connecting microphones.)
The accompanying LED will illuminate red to indicate
that phantom power is active. This is a global switch
that affects all mic channels' XLR jacks at once.
Never plug single-ended (unbalanced)
micro phones, or ribbon mics into the
mic input jacks if phantom power is on.
Do not plug instrument outputs into the mic XLR
input jacks with phantom power on, unless you know
for certain it is safe to do so.
Be sure the main mix
fader is turned down when connecting microphones
to the mic inputs when phantom power is turned on,
to prevent pops from getting through to the speakers.
48V
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