User manual

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.

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