5. OPERATION AND USAGE
Start-up
This can be done using the switch (45) located at the mixer's back panel. Now the LED ON (23) indicator will
highlight. Even if the noise produced while enabling the NUO4.0 is as low as possible and gets completely
cancelled if all faders are turned down, it is always recommendable to turn on the devices using the following
sequence:
1. Sound sources.
2. Mixer, equalizers, active filters.
3. Finally, power amplifiers.
Powering off should be done by following the exact reverse sequence in order to avoid any possible damage to the
loudspeakers.
Control Description
Input selector
Each channel features an input toggle switch selector (1).
Channel GAIN
All the NUO4.0 input channels have an accessible input sensitivity GAIN control (3). The GAIN controls adjust the
input level of each channel in order to compensate the different sources connected to the mixer.
The gain adjustments should be done with great care, using as a reference the VU-meter (2) on each channel. The
standard level reference used to mix audio signals is 0dBV.
The gain margin is set to ±15dB, but can be reduced to ±6dBV. This setting is independent for each channel and
can be done using soldering bridges. See the configuration diagram.
Equalization
The tone control system for each channel offers a wide range of modification from -30 to +10dB for low frequencies
(6) and high frequencies (4) and from -25 to +10dB for middle frequencies (5). This wide range of variation, known
as "kill" type, can completely attenuate the selected frequency range and has been specially designed for creative
usage during live sessions.
ATTENTION: Use equalization carefully, by boosting too much the low frequency range, you can induce an
excessive displacement of the speakers membrane.
Monitoring System
The NUO4.0 is equipped with a flexible and easy monitoring system that will allow the performers to finely tune PFL
(Pre-fader listening) and Mix levels of each input through the VU-METER and the HEADPHONES. Each channel
can be monitorized visually and pre-listened pressing the dedicated PFL (7) button.
For HEADPHONES monitoring, the SELECT rotary potentiometer (28) allows you to blend a selected PFL together
with the main MIX Program. The LEVEL rotary potentiometer (29) controls the level of headphones output.
Each channel has a dedicated VU-meter that allows visual monitoring of the PFL signal (2).
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