Allen&Heath ML3000 USER GUIDE - Manual (Page 20)

20 ML3000 User Guide
MONO INPUT and EQ
+48V. Switches +48VDC to the channel input XLR
for powering microphones or DI boxes that need
phantom power. The power is current limited
through 6800 ohm resistors to pins 2 and 3.
WARNING Do not connect unbalanced
sources or cables to inputs with phantom power
selected. To avoid loud clicks always mute the
channel before switching +48V on or off and
when plugging or unplugging microphones.
GAIN. Adjusts the input sensitivity to match the
connected source to the internal 0dBu operating
level of the channel. Provides a variable 50dB
range from +10 to +60dB gain. The gain should be
set so that the channel meter averages ‘0’ with
loudest moments lighting ‘+6’. Reduce gain if the
red peak meter lights.
PAD. Attenuates the input signal by 20dB for
connection to high level microphone or line sources.
When pad is selected the gain control adjusts from
–10dB attenuation to +40dB gain.
POLARITY. Reverses the polarity of the input
signal. This is used to correct reverse wired cables
or sources, and can be effective in reducing
phasing problems between microphones or acoustic
feedback between the microphone and
loudspeakers.
HPF FREQUENCY. Adjusts the cut off frequency
of the high pass filter from off to 400Hz to reduce
low frequency source noise. The filter attenuates
frequencies below cut off by 12dB per octave.
Using the Filter
Adjust the cut off frequency to clean up sources that
do not have much bass content, for example drum
kit overheads (set to 400Hz), reduce proximity
popping on vocals (set around 150Hz), reduce
handling noise and stage rumble, or protect the
speakers from very low frequency energy (set
around 20 to 50Hz). Turn the filter off by setting the
control fully anti-clockwise to preserve full sub
energy for low frequency sounds such as kick drum,
bass and special effects.
10k 1kHz 100 30k
-35
-40
10
-30
-25
-20
-15
-10
-5
0dB
+5
+10
OFF 400Hz
HIGH PASS FILTER
EQ IN
500Hz 15k
LM
-15
-15
+15
+15
LF
180
-15
35Hz
45
80
+15
400
1k
250
HM
400Hz OFF
2.5k
1k
700
-15 +15
4k
6k
HF
50
10 - 10
20
GAIN
0
20
O
60 40
HPF
200
100
20dB
PAD
40
+48V