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CONTENTS
steel grille and recessed side handles, the cabinet is finished in black
textured paint.
When operated in passive mode the LE12JB can be used without a
controller. Used actively the LE12JB is best operated with DX1 or MX5
controllers to provide crossover, limiting and eq functions. In either mode
sound quality is consistent, enabling mixing of configurations on stage,
without the need to compensate for differing tonal balance. When using the
LE12JB in active mode performance is identical to its predecessor, the
LE12J. A retro-fit kit is available to upgrade this model.
4
The LE12JB is designed to be used with professional power amplifiers
capable of producing 500-700W into 4 ohms:
Care should be taken to avoid amplifier clipping. It is important to
understand that a low power amplifier driven into clipping is more likely to
damage a loudspeaker than a higher power amplifier used within its ratings.
This is because music signals have a high peak-to-average "crest" factor.
When an amplifier is severely overdriven, its output waveform is clipped (its
peaks are squared off) – reducing the crest factor. In extreme cases, the
waveform can approach that of a square wave. An amplifier is normally
capable of producing far more power under these conditions than its
undistorted rated power output.
The use of very high power amplifiers with outputs greater than those
recommended is discouraged.
Care should be taken to avoid switch-on surges, which can result in
momentary power peaks in excess of specified ratings. When powering up
a sound system it is important to switch on the amplifiers after the mixer
and control electronics have stabilised. When powering down the system,
reverse the sequence and switch off the amplifiers first.
5
The LE12JB is fitted with two Neutrik Speakon NL4 connectors wired in
parallel. Do not make a connection to +2, -2 when using the LE12JB in
passive mode.
NL4
-1
+1
-2
+2
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AMPLIFICATION
CONNECTIONS
LE12JB Passive
Martin Audio – LE12JB SERIES MONITOR
LE12JB Active
Input -
Input +
N/C
N/C
3
GUIDES
LF -
LF +
HF -
HF +
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