Installation manual

Page 11NEMS operating manual

3. Operation

3.1 Operation

The NEMS speaker provides noise cancellation when power is

applied to the speaker and it is switched on. Removing the power,

or switching the NEMS off will remove the noise cancellation

and the speaker circuitry will be bypassed. In this mode the

speaker acts as a normal extension speaker.

To check the operation tune the radio into a band where there is

a lot of background noise (turn the squelch off). Turn on the

NEMS, the red led will illuminate in the switch.

The level of noise will drop after a short delay as the DSP adapts

to the noise present on the audio signal. Turn the switch off and

the noise will return.

If the NEMS doesn’t operate as expected the please turn to

section 5 - troubleshooting.

Note:

If a slight pop is heard when the speaker is switched on this is

nothing to worry about and is normal.

There is no need to turn the noise cancelling off if the noise

levels reduce, as the DSP is fully adaptive and will learn the new

noise conditions, and will not interfere with the audio signal.

3.2 Remote operation.

If the NEMS on/off switch is inaccessible due to the chosen

mounting position it is possible to install another switch in the

power line. Leave the NEMS power switch on, and control the

power and noise cancellation with this new switch.