Nexo NXAMP4X1, User Manual

Page: 70 / 140

MENU DESCRIPTION
Load Monitor
This menu allows setting up the NXAMP impedance monitoring function, which allows to
report (through its GPIO port of through the Ethersound network) if the speakers are
correctly connected to the amplifier and ready to be used. This is particularly useful for
safety installations where the status of the connected speakers should always be known,
and any default in the audio chain should be reported.
There is two way of using the load monitor function:
1) Either the NXAMP uses the internal HF burst generator and measure the impedance of
the connected speakers for each channel at this frequency.
2) The NXAMP internal HF burst generator is OFF and the audio program sent to the
NXAMP contains a HF pilot tone; the impedance of the speakers can still be monitored
at the pilot tone frequency.
Thanks to the 24 bits 48 KHz current and voltage sense circuitry only a small HF burst
voltage is needed in most of the case (typically 1 volt).
To access the Load Monitor menu, go to the “OPTION” menu, and select the sub-menu 6.
Load Monitor . The following display will then appear.
You can see several zones in grey on the picture above. Here are the details for these
zones:
(1) Internal HF burst generator / External Pilot Tone frequency
Here you can adjust the frequency where the impedance measurement will be done for the
speaker(s) connected to the channel selected in the zone 6. The frequency is adjustable
from 14500 to 21100 Hz, in 1/12 octave steps. Most of the time, there is no need to
change this frequency if internal burst generator is ON.
1
7
6 5 4 3 2
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