Allen&Heath GL3000 - Manual (Page 10)

10 GL3000 U SER G UIDE ISS .1
INPUT CHANNELS
Plug in a microphone or line level source. Use
balanced cables where possible to prevent
interference pickup on long cable runs.
Unbalanced sources may be connected by
linking signal cold to ground (XLR pin 3 to pin
1, jack ring to sleeve) at the connector.
For line sources on XLR simply
plug into the XLR with the jack
socket unplugged.
For balanced microphones which require
phantom power select +48V. If required this
switch may be disabled by an internal link.
Switch off channel +48V when the inputs are connected to non-
phantom powered, line or unbalanced sources.
)
Use the PFL system to listen
to the signal and fine tune the
gain setting.
INSERT lets you plug in external
effects and signal processing
equipment into the signal path.
Operate at around 0dBu line level.
MONO
STEREO
φφφφφ PHASE reverses the phase of the input
source to correct the phase differences often
encountered in microphone placement, or due
to incorrectly wired cables (pin 3 hot instead of
pin 2). May also be used to minimise acoustic
feedback between closely positioned
loudspeakers and mics in live sound mixing.
The stereo
φφφφφL reverses the left input phase
only to correct for differences between left and
right signals, or for MS microphone techniques.
MIC/LINE selects line sensitivity on the jack
input when pressed. Or becomes a 20dB pad for
the XLR input when no jack is plugged in.
GAIN matches the level of the input source to
the normal operating level of the console. Adjust
this to read an average '0dB' on the channel
meter (yellow LED). Use the PFL system to
listen to the signal and fine tune the gain.
100Hz lo-cut filter removes low frequency noise
such as microphone pops, stage noise and
transport rumble before the pre-amp stage. The
lo-cut filter is independent of the equaliser.
The 4-band EQ lets you adjust the tonal
quality of the sound in 4 separate bands. HF
(treble) and LF (bass) are shelving while the 2
mid bands are peak/dip with a Q of 1.6. This is
optimum for both corrective and creative
equalisation. The controls are centre detented
for centre flat response. Press EQ IN to switch
the EQ into the signal path.
Both L and R up gives you a
true stereo channel. Press both
to mono the source. Press just
one to select one side only as
a mono source.
Separate GAIN
controls for L and R
inputs let you
adjust the balance
between the
sources, or treat
each as a separate
source.
The 2 mid frequency bands may be swept across a
wide frequency range to tune into the exact frequency
required, most useful for getting the best out of
microphones or when tuning out troublesome
feedback. The mid bands are overlapping to provide
additional cut or boost when required, or provide a
tailored response to suit any application. The 4-band stereo EQ puts the 2 mid frequencies at
250Hz and 2.5kHz. This provides optimum control
over boomy or boxy sounds (250Hz), and to add bite
or reduce harshness to keyboards, vocals etc.
(2.5kHz). The stereo channels are well suited to
stereo miking, dual mic mixing, or returning
keyboards and effects processors to the mix and
monitors.