Bosch PRAESENSA Installation Manual page 75

PRAESENSA
Dual line (A + B)
If loudspeaker line redundancy is needed, then follow the procedure below to connect two
loudspeaker lines, one to output A and one to output B. Typically the loudspeakers are
mounted alternating A, B, A, B, and so on, half the number connected to A, half the number
connected to B.
When one loudspeaker line fails this may result in the loss of half the number of loudspeaker
and with proper positioning of the loudspeakers the acoustic output level will drop by
3 dBSPL. A loudspeaker line fault will be reported.
1.
2.
3.
4.
Bosch Security Systems B.V.
D
+ +
Connect half of the loudspeakers in parallel in a loop‑through fashion to output A.
Observe polarity.
– Follow the same wiring procedure as for using a single line.
Connect an end-of-line device to the end of loudspeaker line A.
Repeat this procedure for the other half of the loudspeakers and connect them to output
B.
Connect an end-of-line device to the end of loudspeaker line B. Loudspeaker lines A and
B must be separately supervised, each with its own end-of-line device. In case of a short
circuit in one of the loudspeaker lines, the amplifier will diagnose the overload condition
to find the affected loudspeaker line and switch‑off that line, so the other loudspeaker
line can continue operation.
*Amplifier, 600W 4-channel | PRA-AD604 | en
PRA-EOL
Installation manual
75
2019.11 | V1.00 |