Setup; Setting Up The Minimum Configuration; Connecting Speakers To The Mevac-4 System; Polarity Of Amplifiers And Speaker Connections - Monacor MEVAC-4 Bedienungsanleitung

4 Setup

In a fully configured MEVAC-4 system, a separate power ampli-
fier is assigned to each audio output (see connection example
in chapter 5.7). Consequently, with the additional spare ampli-
fier, five power amplifiers are required. Each power amplifier
is connected to a line audio output and a 100 V input. Thus
it is possible to play background music in a zone while an
announcement is being made in another zone.
WARNING Prior to connecting units or changing exist-
ing connections, always switch off MEVAC-4
and the units to be connected! The speaker
cables carry dangerous voltage. Contact with
the speaker cables may result in electric shock.

4.1 Setting up the minimum configuration

The setup of a minimum configuration only requires two
amplifier channels. For a perfect protection against failure of
an amplifier, two separate power amplifiers are recommended:
one amplifier to be used as the standard amplifier, the other
as the spare amplifier:
Fig. 4 Connection of a standard amplifier
Connect the line input of the standard amplifier to one of
the output jacks OUT CH1 to OUT CH4 of MEVAC-4 (in this
example: OUT CH1). Connect the 100 V output of the stand-
ard amplifier to the inputs of the zones 1 – 4 (in this example,
only the connection to CH1 AMP IN is shown. CH2, CH3 and
CH4 AMP IN must be connected in the same way, also see
chapter 7.2.2).
Fig. 5 Connection of a spare amplifier
Connect the line input of the spare amplifier to the output
jack OUT SPARE of MEVAC-4. Connect the 100 V output of the
spare amplifier to the input SPARE AMP IN of MEVAC-4. This
configuration will make sure that the spare amplifier monitors
the inactive zones; however, it will not be possible to play back-
ground music and make announcements at the same time.
4.2 Connecting speakers
to the MEVAC-4 system
The speaker lines are designed as A / B wires according to
the regulations of current standards such as EN54-24 and
EN60849: the speakers of a zone are divided into two sep-
arate groups and are connected to the MEVAC-4 system via
separate lines. Thus it is possible to monitor the lines sepa-
rately. With this configuration, only half of the speakers will
be inoperative and, as a result, the sound level will only drop
by a maximum of 3 dB when a line fails (assuming that the
total speaker power for the two output paths (A / B) within a
line is approx. the same).
Fig. 6 Speaker connection
4.2.1 Polarity of amplifiers and
speaker connections
To prevent signal loss by phase cancellations, ensure a correct
and constant polarity of the speakers and amplifiers connected.
The following figure shows one of the polarities possible.
Fig. 7 Possible polarity

4.2.2 Admissible deviation

The system will generate an error message when the total
impedance of the line (path A + path B) deviates by
+20 W/ −10 W for impedance deviation "NORMAL" or
+10 W/ −6 W for impedance deviation "SMALL",
see chapters 7.4 and 9.2.4, or more
from the value measured during the installation run. In order
to avoid unfounded error messages (e.g. caused by specific
weather conditions), the impedance deviation "NORMAL" is
strongly recommended.
For measuring purposes, the speaker network is supplied with
a 22 kHz pilot tone of approx. −16 dBu. The 22 kHz tone is
internally generated by MEVAC-4 and is not the measuring
tone stored on the memory card.
Attention: All values are approximate values and refer to the
behaviour of the speakers / transformers /controls for a measur-
ing frequency of 22 kHz. These values deviate from the 1 kHz
values stated on the units!
B
A
100 V IN 100 V IN
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