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VLS Series Operation Manual rev 1.1.0
6. Polarity checking
All transformer primaries should be connected in parallel to the output of the amplifier. The summed total
power rating in watts of the selected tap settings for all connected loudspeakers must not exceed the total
output power rating of the connected amplifier output channel in watts. It is recommended that a generous
power safety margin (minimum 3 dB headroom) be maintained between the total loudspeaker power
requirements and the amplifier output capacity to avoid continuous amplifier operation at full rated output.
5.4 Wiring for EN54 and outdoor applications
A right angled water tight cable gland is supplied with the VLS 7 and 15 for use in outdoor applications (Fig.1).
The VLS 30 has an input panel cover with rubber wiring grommet for use in outdoor applications (Fig.2).
Before making connections, pass the wire(s) through the cable grand/rubber grommet. The input panel cover is
secured to the cabinet using the four screws already inserted around the input.
Fig.1 VLS 7 & VLS 15
Fig.2 VLS 30
6. Polarity checking
Checking the polarity of the wiring before the speaker system is mounted or flown will help ensure satisfactory
performance. If you do not have a pulse-based polarity checker, you may check LF units as follows: Connect
two wires to the + and - terminals of a PP3 (9 V) battery. Apply the wire connected to the positive (+) terminal
of the battery to the speaker cable leg which you believe to be connected the positive terminal of the speaker
connector; likewise connect the negative (-) terminal of the battery to the negative terminal of the speaker. If
you have wired it correctly, the LF drive unit will move forward. At this point, connect the positive (+) speaker
lead to the + terminal on the amplifier and the negative (-) lead to the - terminal on the amplifier. However, if
the LF driver moves backwards with the battery test, the input connections need to be inverted before
connecting the amplifier. If problems are encountered, inspect the cable wiring. Note that different amplifier
manufacturers may utilise different pin configurations and polarity conventions; if you are using amplifiers from
more than one manufacturer, check the polarity at the amplifiers as well as at the loudspeakers.
