Axis 2N LiftIP User Manual page 23

Accident Risk
Mount the 50mm speaker on an insulating (non-metallic) surface only or
require an external panel (not included in the delivery), see the figure
below.
Caution
We do not recommend you to install the microphone and speaker on
completely different cabin sites (ceiling and wall, e.g.) as the users
should find the speaker (grid/perforation) easily and then speak into the
microphone near it.
Caution
You are recommended to turn down the speaker volume to minimise the
microphone-speaker feedback (echo).
How to Achieve Ideal Acoustic Properties
To ensure the minimum acoustic pressure according to the EN 81-28:2015 standard
requirements, the holes in the communicator speaker covering panel should occupy
20 % of the speaker area at least and be placed above the speaker.
Make sure that the speaker and the microphone fit tightly to the covering panel. If this
is impossible due to panel surface unevenness, we recommend you to seal the speaker
to avoid speaker sound leakage into the space behind the panel. A correct
microphone installation is crucial for high-quality audio transmission and good
intelligibility.
Try to minimise the acoustic feedback between the speaker and the microphone
during installation.
2N TELEKOMUNIKACE a.s., www.2n.cz 23/117