Martin Audio – LE12JB SERIES MONITOR
CONTENTS (ENGLISH) Page No
1 INTRODUCTION 2
2 UNPACKING 2
3 OVERVIEW 2
4 AMPLIFICATION 3
5 CONNECTIONS 3
6 CABLE LENGTHS 4
7 WARRANTY 4
8 TECHNICAL SPECIFICATIONS 5
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MARTIN AUDIO
LONDON
1 INTRODUCTION
Thank you for purchasing a Martin Audio LE Series monitor. LE Series
monitors have always set the industry standard for touring and stage
applications. All LE Series monitors except the LE400C utilise differential
dispersion horn technology to define a high frequency coverage footprint
that is particularly useful for stage monitor applications.
2 UNPACKING
Each Martin Audio loudspeaker is built to the highest standard and
thoroughly inspected before it leaves the factory. After unpacking the
system, examine it carefully for any signs of transit damage and inform your
dealer if any such damage is found. It is suggested that you retain the
original packaging so that the system can be repacked at a future date if
necessary. Please note that Martin Audio and its distributors cannot accept
any responsibility for damage to any returned product through the use of
non-approved packaging.
3 OVERVIEW
The LE12JB is a two-way active/passive switchable, multi-angled enclosure
fitted with a high sensitivity 12" (305mm) / 3" (75mm) coil driver handling
low frequencies up to the 1.3kHz crossover point. High frequencies are
reproduced by a 1.4" (35mm) exit titanium diaphragm compression driver
loaded by a proprietary differential dispersion 50˚-100˚ horizontal x 70˚
vertical horn.
The differential dispersion horn varies its horizontal dispersion from wide to
narrow as the performer moves back from the monitor. This narrowing
dispersion effectively changes the forward gain of the horn which enables
the horn to throw further, increasing the operating range of the monitor and
reducing excess spill. As the performer moves closer to the monitor the
dispersion widens giving the performer the ability to hear themselves clearly
even when positioned directly above or to the left or right of the monitor.
The multi-angled enclosure is of multi-laminate birch ply construction and is
available in left and right-handed versions. Incorporating a tough punched
Martin Audio – LE12JB SERIES MONITOR
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This equipment conforms to the requirements of the
EMC Directive 89/336/EEC, amended by 92/31/EEC
and 93/68/EEC and the requirements of the Low
Voltage Directive 73/23/EEC, amended by 93/68/EEC.
Standards Applied EMC Emission EN55103-1:1996
Immunity EN55103-2:1996
Electrical Safety EN60065:1993
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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. Aretro-fit kit is available to upgrade this model.
4 AMPLIFICATION
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 CONNECTIONS
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
LE12JB Passive LE12JB Active
-1 Input - LF +1 Input + LF +
-2 N/C HF +2 N/C HF +
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6 CABLE LENGTHS
When connecting loudspeaker systems to an amplifier, it is recommended
that the return resistance of the cable used is less than one tenth of the
nominal impedance of the system or systems in parallel. The table below
gives an indication of the maximum permissible cable runs for various
conductor cross-sectional areas.
Conductor CSA
Maxim
um Cable Run
4 ohms 8 ohms 16 ohms
1.0mm
2
11m 22m 44m
1.5mm
2
17m 34m 68m
2.0mm
2
22m 44m 88m
2.5mm
2
29m 58m 116m
4.0mm
2
44m 88m 176m
6.0mm
2
66m 132m 264m
7 WARRANTY
Martin Audio LE12JB monitors are warranted against manufacturing defects
in materials or craftsmanship over a period of 5 years from the date of
original purchase. During the warranty period Martin Audio will, at it’s
discretion, either repair or replace products which prove to be defective
provided that the product is returned in its original packaging, shipping
prepaid, to an authorised Martin Audio service agent or distributor.
Martin Audio Ltd. cannot be held responsible for defects caused by
unauthorised modifications, improper use, negligence, exposure to
inclement weather conditions, act of God or accident, or any use of this
product that is not in accordance with the instructions provided by Martin
Audio. Martin Audio is not liable for consequential damages.
This warranty is exclusive and no other warranty is expressed or implied.
This warranty does not affect your statutory rights.
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8 TECHNICAL SPECIFICATIONS
LE12JB
TYPE Two-way reflex enclosure with
differential dispersion HF horn
FREQUENCY RESPONSE (1) 65Hz-18kHz ±3dB
DRIVERS 12” (305mm) dia. 3” (75mm) voice coil
1.4” (35mm) exit compression driver
RATED POWER (2) FR/LF: 300W AES, 1200W peak.
HF: 75W AES, 300W peak.
RECOMMENDED AMPLIFIER 500-700W into 4 ohms
SENSITIVITY (3) FR: 97dB 1 Watt/1 metre
LF: 98dB 1 Watt/1 metre
HF: 106dB 1 Watt/1 metre
MAXIMUM SPL (4) FR: 120dB continuous, 126dB peak
LF: 121dB continuous, 127dB peak
HF: 124dB continuous, 130dB peak
IMPEDANCE FR: 8 ohms nominal
LF: 8 ohms nominal
HF: 16 ohms nominal
CROSSOVER 1.3 kHz passive/active
DISPERSION (-6dB) 50˚-100˚ horizontal, 70˚ vertical
ENCLOSURE 38 litre (1.3cu foot)
multi-laminate birch ply
FINISH Textured black paint
PROTECTIVE GRILLE Black perforated steel
CONNECTORS 2 x Neutrik NL4
FITTINGS 2 x recessed side handles
DIMENSIONS (W) 607mm x (H) 343mm x (D) 434mm
(W) 23.9ins x (H) 13.5ins x (D) 17.1ins
WEIGHT 27.5kg (60lbs)
SHIPPING DIMENSIONS (W) 710mm x (H) 420mm x (D) 510mm
(W) 28ins x (H )16.5ins x (D) 20.1ins
SHIPPING WEIGHT 29.8kg (66lbs)
Notes
1. Measured on-axis in half space at 2 metres, then referred to 1 metre.
2. AES Standard ANSI S4.26-1984.
3. Measured in half space conditions at 2 metres with 1 watt input, using band limited pink noise,
then referred to 1 metre.
4. Measured in half space conditions at 2 metres using band limited pink noise, then
referred to 1 metre.
Due to our policy of continuous improvement all specifications are subject
to change without notice.
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LE12JB Series Monitor
Century Point, Halifax Road, Cressex Business Park, High Wycombe, Buckinghamshire HP12 3SL, England.
Telephone: +44 (0)1494 535312 Facsimile: +44 (0)1494 438669
Web: www.martin-audio.com E-mail: info@martin-audio.com
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MARTIN AUDIO
LONDON
The Martin Experience
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LE12JB Series Monitor
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