Owner's Manual

Page 78/112 NEXO NX242-ES4 DIGITAL CONTROLLER FOR GEO S12
The Physio control voltage acts independently on the VCA with its operation threshold slightly (3 dB)
above that of the temperature limiter and a low compression ratio; its optimised attack time constant
allows it to start operating without any subjectively unpleasant transient effects.
Peak Limiter
The peak limiter primary function is to avoid massive clipping of the amplifier, which can have some
very audible artefacts and in some cases may be damaging to the loudspeakers. Modulation of the
amplifier’s supply voltage rails can create very low frequencies or high-frequency, high level harmonics.
Since these occur after the NX242 in the signal path, they are not filtered by the TDcontroller circuitry.
The threshold of the peak limiter is set by the user to match the amplifier’s clipping point.
The second function of the peak limiter is to avoid huge amounts of power being sent to a driver. Each
driver is protected against overheating and overexcursion, but there could be other failure modes that
cannot be predicted by simulation (especially mechanical damage to the cone). Each driver is specified
for a certain power handling and a factory set peak limiter threshold is tuned to avoid any abuse.
10.2 Trouble shooting
The NX242 has been designed to be user-friendly. However with highly technical systems such as GEO
S12, incorrect adjustment of the NX242 can lower the quality & safety of your system. Listed below are
the most common errors encountered by NEXO Technical Support.
10.2.1 Operation of Multiple TDcontrollers output channels
Typically, GEO S12 systems require multiple NX242’s output channels per side. Eventually, two or
more NX242’s channels will operate within the same cluster. It is mandatory to verify the consistency of
the setups and adjustment between these channels to avoid the problems described below.
IMPORTANT
When using multiple NX242’s output channels in a single array, all parameters should be
consistent and set to proper values on each channel.
10.2.2 Amplifier Power (MENU 2.7)
If the amplifier power (MENU 2.7) is set to a value below the amplifer’s actual power, the peak limiter of
the NX242 will trigger continually, creating audible distortion. Please note that this peak limiter is not set
to act as a compressor on the signal. It is intended to minimize the clipping of the amplifier by operating
slightly after
the amplifier’s clipping point.
One way to properly adjust this parameter is to set amplifier power at maximum (5000W) and decrease
the value until the amplifier and TDcontroller clip at the same time.
10.2.3 Amplifier Gain (MENU 2.6)
It is very important to check the gain of each channel. These values should be set in agreement with
amplifier gain. The second line of the MENU2.6 displays the gain as seen by the NX242 to ease the
setting of this parameter.
10.2.4 Gains
If your amplifier gains are not the same on each channel, you will have to adjust the inter-channel gain
in order to compensate for this amplifier gain difference.