OPERATING INSTRUCTIONS
JM-1P Arrayable Loudspeaker
JM SERIES
Keep these important operating instructions.
Check www.meyersound.com for updates.
DECLARATION OF CONFORMITY ACCORDING TO ISO/IEC GUIDE 22 AND EN 45014
Manufacturer’s Name: Meyer Sound Laboratories Inc.
Manufacturer’s Address: 2832 San Pablo Avenue
Berkeley, CA 94702-2204, USA
Declares that the product:
Product Names: JM-1P Arrayable Loudspeaker
Product Options: All
Conforms to the following Product Specifications:
Safety: EN 60065:2002
EMC:
EN55103-1: 1997 emission
EN55103-2: 1997 immunity
This device also complies with EN 55103-1 & -2. Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including interference
that may cause undesired operation.
Supplementary Information: The product herewith complies with the requirements of the Low Voltage
Directive (LVD) 2006/95/EC and the EMC Directive 2004/108/EC.
Signature:
1
2
Ms. Margie Garza
Director of Quality
Meyer Sound Laboratories Inc.
Berkeley, California 94702 USA
Issued November 3, 2009
European Contact:
Your local Meyer Sound dealer or
Meyer Sound Germany, GmbH.
© 2009
Meyer Sound. All rights reserved.
JM-1P Operating Instructions, PN 05.202.005.01 A
The contents of this manual are furnished for informational purposes only, are subject to change without notice, and should not be construed as a commitment by Meyer Sound Laboratories Inc. Meyer Sound assumes no responsibility or liability for any errors or inaccuracies that may appear in this manual. Except as permitted by applicable copyright law, no part of this publication may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, recording or otherwise, without prior written permission from Meyer Sound.
GuideALink, Intelligent AC, JM-1P, MAPP Online Pro, RMS, QuietCool, and all alpha-numeric designations for Meyer Sound products and
accessories are trademarks of Meyer Sound. Compass, Galileo, Meyer Sound, the Meyer Sound wave logo, QuickFly, and SIM are registered trademarks of Meyer Sound Laboratories Inc. (Reg. U.S. Pat. & Tm. Off.). All third-party trademarks mentioned herein are the property of their respective trademark holders.
Printed in the USA.
ii
SYMBOLS USED
!
!
!
These symbols indicate important safety or operating features in this booklet and on the chassis:
Dangerous voltages: risk of
electric shock
Pour indiquer les risques
résultant de tensions dangereuses
Warnung vor gef
elektrischer Spannung
Para indicar voltajes peligrosos Instrucciones importantes de
ährlicher
Important operating instructions Frame or chassis Protective earth ground
Pour indequer important
instructions
Wichtige Betriebsanweisung oder
Gebrauchsanleitung
funcionamiento y/o manteniento
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this loudspeaker near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with Meyer Sound’s installation instructions.
8. Do not install near any heat sources such as radiators,
heat registers, stoves, or other apparatus that produce
heat.
9. Do not defeat the safety purpose of the grounding-type
plug. A grounding type plug has two blades and a third
grounding prong. The third prong is provided for your
safety. If the provided plug does not fit into your outlet,
consult an electrician for replacement of the obsolete
outlet.
10.Protect the power cord from being walked on or pinched,
particularly at plugs, convenience receptacles, and the
point where they exit from the loudspeaker. The AC
mains plug or appliance coupler shall remain readily
accessible for operation.
Masse, châssis Terre de protection
Rahmen oder Geh
Armadura o chassis Tierra proteccionista
äuse
Masse Schutzleiter
11.Only use attachments/accessories specified by Meyer
Sound.
12.Use only with the caster rails or rigging specified by
Meyer Sound, or sold with the loudspeaker. Handles are
for carrying only.
CAUTION: Rigging should only be done by
experienced professionals.
13.Unplug this loudspeaker during lightning storms or when
unused for long periods of time.
14.Disconnect the mains plug before disconnecting the
power cord from the loudspeaker.
15.Refer all servicing to qualified service personnel. Servicing is required when the loudspeaker has been damaged
in any way, such as when the power-supply cord or plug
has been damaged; liquid has been spilled or objects
have fallen into the loudspeaker; rain or moisture has
entered the loudspeaker; the loudspeaker has been
dropped; or when for undetermined reasons the loudspeaker does not operate normally.
CAUTION: To reduce the risk of electric shock,
do not expose this loudspeaker to rain or moisture. Do not install the loudspeaker in wet or humid
locations without using weather protection equipment from Meyer Sound.
iii
SAFETY SUMMARY
English
To reduce the risk of electric shock, dis-
connect the loudspeaker from the AC
mains before installing audio cable.
Reconnect the power cord only after
making all signal connections.
Connect the loudspeaker to a two-pole,
three-wire grounding mains receptacle.
The receptacle must be connected to a
fuse or circuit breaker. Connection to
any other type of receptacle poses a
shock hazard and may violate local
electrical codes.
Do not install the loudspeaker in wet or
humid locations without using weather
protection equipment from Meyer
Sound.
Do not allow water or any foreign object
to get inside the loudspeaker. Do not
put objects containing liquid on or near
the unit.
To reduce the risk of overheating the
loudspeaker, avoid exposing it to direct
sunlight. Do not install the unit near
heat-emitting appliances, such as a
room heater or stove.
This loudspeaker contains potentially
hazardous voltages. Do not attempt to
disassemble the unit. The unit contains
no user-serviceable parts. Repairs
should be performed only by factorytrained service personnel.
Français
Pour réduire le risque d’électrocution,
débrancher la prise principale de l’hautparleur, avant d’installer le câble d’interface allant à l’audio. Ne rebrancher le
bloc d’alimentation qu’après avoir
effectué toutes les connections.
Branchez l’haut-parleur dans une prise
de courant à 3 dérivations (deux pôles
et la terre). Cette prise doit être munie
d’une protection adéquate (fusible ou
coupe-circuit). Le branchement dans
tout autre genre de prise pourrait
entraîner un risque d’électrocution et
peut constituer une infraction à la réglementation locale concernant les installations électriques.
Ne pas installer l’haut-parleur dans un
endroit où il y a de l’eau ou une humidité excessive.
Ne pas laisser de l’eau ou tout objet
pénétrer dans l’haut-parleur. Ne pas
placer de r´cipients contenant un liquide
sur cet appareil, ni à proximité de celuici.
Pour éviter une surchauffe de l’haut-
parleur, conserver-la à l’abri du soleil.
Ne pas installer à proximité d’appareils
dégageant de la chaleur tels que radiateurs ou appareils de chauffage.
Ce haut-parleur contient des circuits
haute tension présentant un danger. Ne
jamais essayer de le démonter. Il n’y a
aucun composant qui puisse être
réparé par l’utilisateur. Toutes les réparations doivent être effectuées par du
personnel qualifié et agréé par le constructeur.
Deutsch
Um die Gefahr eines elektrischen
Schlages auf ein Minimum zu
reduzieren, den Lautsprecher vom
Stromnetz trennen, bevor ggf. ein
Audio-Schnittstellensignalkabel angeschlossen wird. Das Netzkabel erst
nach Herstellung aller Signalverbindungen wieder einstecken.
Der Lautsprecher an eine geerdete
zweipolige Dreiphasen-Netzsteckdose
anschließen. Die Steckdose muß mit
einem geeigneten Abzweigschutz
(Sicherung oder Leistungsschalter) verbunden sein. Der Anschluß der unterbrechungsfreien Stromversorgung an
einen anderen Steckdosentyp kann zu
Stromschlägen führen und gegen die
örtlichen Vorschriften verstoßen.
Der Lautsprecher nicht an einem Ort
aufstellen, an dem sie mit Wasser oder
übermäßig hoher Luftfeuchtigkeit in
Berührung kommen könnte.
Darauf achten, daß weder Wasser noch
Fremdkörper in das Innere den
Lautsprecher eindringen. Keine
Objekte, die Flüssigkeit enthalten, auf
oder neben die unterbrechungsfreie
Stromversorgung stellen.
Um ein Überhitzen dem Lautsprecher
zu verhindern, das Gerät vor direkter
Sonneneinstrahlung fernhalten und
nicht in der Nähe von wärmeabstrahlenden
Haushaltsgeräten (z.B. Heizgerät oder
Herd) aufstellen.
Im Inneren diesem Lautsprecher herr-
schen potentiell gefährliche Spannungen. Nicht versuchen, das Gerät zu
öffnen. Es enthält keine vom Benutzer
reparierbaren Teile. Reparaturen dürfen
nur von ausgebildetem Kundenienstpersonal durchgeführt werden.
Español
Para reducir el riesgo de descarga eléc-
trica, desconecte de la red de voltaje el
altoparlante antes de instalar el cable
de señal de audio. Vuelva a conectar la
alimentacion de voltaje una vez efectuadas todas las interconexiones de
señalizacion de audio.
Conecte el altoparlante a un tomacorri-
ente bipolar y trifilar con neutro de
puesta a tierra. El tomacorriente debe
estar conectado a la protección de derivación apropiada (ya sea un fusible o un
disyuntor). La conexión a cualquier otro
tipo de tomacorriente puede constituir
peligro de descarga eléctrica y violar los
códigos eléctricos locales.
No instale el altoparlante en lugares
donde haya agua o humedad excesiva.
No deje que en el altoparlante entre
agua ni ningún objeto extraño. No
ponga objetos con líquidos encima de
la unidad ni cerca de ella.
Para reducir el riesgo de sobrecalen-
tamiento, no exponga la unidad a los
rayos directos del sol ni la instale cerca
de artefactos que emiten calor, como
estufas o cocinas.
Este altoparlante contiene niveles de
voltaje peligrosos en potencia. No
intente desarmar la unidad, pues no
contiene piezas que puedan ser repardas por el usuario. Las reparaciones
deben efectuarse únicamente por parte
del personal de mantenimiento capacitado en la fábrica.
iv
CONTENTS
Chapter 1: Introduction 7
How to Use This Manual 7
Introducing the JM-1P Loudspeaker 7
Chapter 2: Power Requirements 9
AC Power Distribution 9
The AC Connectors 9
Power Connector Wiring 10
JM-1P Voltage Requirements 10
JM-1P Current Requirements 11
Electrical Safety Issues 12
Chapter 3: Amplification and Audio 13
VEAM Cabling 13
The Looping Audio Input Module 13
Amplifier Cooling System 15
Chapter 4: Adding Subwoofers to a JM-1P Loudspeaker System 17
The Galileo® Loudspeaker Management System 17
Using Digital Signal Processors 18
Chapter 5: QuickFly® Rigging 19
The JM-1P GuideALinks™ 19
The MPA-JM1 Pickup Plate 21
The MTG-JM1 Vertical Grid 24
The MDB-JM1 Dolly Board 25
Chapter 6: The RMS™ Remote Monitoring System 27
The RMS Software 27
The RMS Module 28
Resetting the RMS Module 29
Chapter 7: System Design and Integration Tools 31
MAPP Online Pro™ 31
The SIM
®
3 Measurement System 32
Appendix A: Optional VEAM Multipin Connector 33
Appendix B: Optional Rain Hoods 35
Appendix C: JM-1P Specifications 39
v
CONTENTS
vi
CHAPTER 1: INTRODUCTION
!
HOW TO USE THIS MANUAL
Make sure to read these operating instructions in their
entirety before configuring a loudspeaker system with
JM-1P loudspeakers. In particular, pay close attention to
material related to safety issues.
As you read these operating instructions, you will encounter
the following icons for notes, tips, and cautions:
NOTE: A note identifies an important or useful
piece of information relating to the topic under
discussion.
TIP: A tip offers a helpful tip relevant to the topic
at hand.
CAUTION: A caution gives notice that an
action may have serious consequences and
could cause harm to equipment or personnel, or
could cause delays or other problems.
Information and specifications are subject to change.
Updates and supplementary information are available on the
Meyer Sound website:
INTRODUCING THE JM-1P LOUDSPEAKER
The JM-1P self-powered loudspeaker is a high-Q, arrayable
loudspeaker suited for a wide range of applications. Utilizing
Meyer Sound's patented REM™ technology and trapezoidal
cabinet design, the JM-1P can be deployed in tightlypacked array clusters to deliver coverage that is proportional to the number of units in the array. While JM-1P point
source arrays are optimized for horizontal installations, they
can also be used vertically when necessary. With its scalable coverage and versatile QuickFly
JM-1P loudspeaker can be used for touring, rental, and
fixed installations.
®
rigging options, the
http://www.meyersound.com
Meyer Sound Technical Support is available at:
Te l: +1 510 486.1166
Fax: +1 510 486.8356
Email: techsupport@meyersound.com
JM-1P Arrayable Loudspeaker
Boasting a wide operating frequency range of 53 Hz to
18 kHz, the JM-1P delivers a remarkably smooth sound with
ample low-frequency headroom. Designed and manufactured at Meyer Sound headquarters in Berkeley, California,
the JM-1P's drivers include one low-frequency 15-inch long
excursion cone driver, and one high-frequency 4-inch compression driver with an REM manifold coupled to an
extremely accurate horn. The JM-1P is distinguished by its
constant-Q horn that provides a 20-degree horizontal by 60degree vertical coverage. The unit's consistent polar
response and trapezoidal enclosure allow for tightly packed
arrays with minimal overlap in high frequencies.
7
CHAPTER 1: INTRODUCTION
The JM-1P's sophisticated onboard amplification and processing produces consistent and predictable results in any
system design. A proprietary two-channel, class AB/H
power amplifier with complementary MOSFET output stages
yields a total power output of 1275 W (2550 W peak). Builtin signal processing includes an electronic crossover, driver
protection, and correction filters for achieving flat phase and
frequency responses. Each amplifier channel has peak and
rms limiters that prevent driver overexcursion and regulate
voice coil temperatures. Limiting activity is easily monitored
with the rear panel limit LEDs. The optional RMS™ remote
monitoring system provides comprehensive monitoring of
system parameters on a Windows
®
-based computer.
The JM-1P's end plates include captive GuideALinks™ and
quick-release pins that allow the unit to be easily linked with
other JM-1Ps in arrays. The optional MPA-JM1 pickup plate
suspends JM-1P horizontal arrays of up to four units with
uptilt or downtilt from a single hanging point; two pickup
plates can suspend arrays of up to six units from a single
hanging point or motor using the MTGSB-4B spreader bar.
The optional MTG-JM1 grid suspends vertical arrays of up
to six JM-1Ps.
MTG-JM1 Vertical Grid with Two JM-1Ps
Constructed of premium birch plywood, the durable JM-1P
enclosure is coated with a black-textured, hard-shell finish.
A hex-stamped, steel grille with acoustical black mesh protects the unit's drivers. Other options include weather protection and custom color finishes for fixed installations and
applications with specific cosmetic requirements. The
optional MDB-JM1 dolly board transports the JM-1P on
caster wheels; multiple dolly boards can be interlocked to
transport up to three linked JM-1Ps.
JM-1P Horizontal Array with MPA-JM1 Pickup Plates and MTGSB-4B
Spreader Bar
8
CHAPTER 2: POWER REQUIREMENTS
!
Line 1
Line 2 Line 3
Neutral
Earth Ground
!
The JM-1P loudspeaker combines advanced loudspeaker
technology with equally advanced power capabilities.
Understanding power distribution, voltage and current
requirements, as well as electrical safety issues, is critical to
the safe operation of the JM-1P.
AC POWER DISTRIBUTION
All components in an audio system (self-powered loudspeakers, processors, etc.) must be properly connected to
an AC power distribution system, ensuring that AC line
polarity is preserved, and that all grounding points are connected to a single node or common point using the same
cable gauge as the neutral and line cables.
NOTE: Improper grounding connections
between loudspeakers and the rest of the
audio system may produce noise or hum, or cause
serious damage to the input and output stages of the
system’s electronic components.
CAUTION: Before applying AC power to any
Meyer Sound self-powered loudspeaker, make
sure that the voltage potential difference between
neutral and earth ground is less than 5 V AC.
Figure 1 illustrates a basic three-phase AC distribution system with the loudspeaker load distributed across the three
phases. All loudspeakers are connected to common neutral
and earth-ground points.
THE AC CONNECTORS
The user panel on the back of the JM-1P includes the fol-
®
lowing PowerCon
JM-1P AC Input (left) and AC Loop Output (right) Connectors
AC connectors:
The AC Input Connector (Blue)
The blue AC Input connector supplies power to the JM-1P.
The connector is rated at 20 amps and uses a PowerCon AC
mains locking connector that prevents accidental disconnections. A 10-foot AC power cable, rated at 15 amps, is
included with each loudspeaker. If you replace the included
AC power cable, make sure to use a cable with the appropriate power plug (on the other end) for the area in which you
will operate the unit.
The AC Input connector also supplies power to any additional loudspeakers connected to the loudspeaker’s gray
Loop Output connector. Each JM-1P loudspeaker requires
approximately 5 A rms (maximum long-term continuous
current) at 115 V AC for proper operation.
Figure 1: AC Power Distribution System
CAUTION: When using the included AC power
cable, do not loop more than two additional
JM-1P loudspeakers from the AC Loop Output connector at 115 V (three total for the circuit), and not
more than five at 230 V (six total for the circuit).
The AC Loop Output Connector (Gray)
The gray AC Loop Output connector allows multiple JM-1P
loudspeakers to be looped and powered from a single
power source. Connect the AC Loop Output of the first
loudspeaker to the AC Input of the second, and so forth. The
AC Loop Output uses a PowerCon3 AC mains locking connector that prevents accidental disconnections.
9
CHAPTER 2: POWER REQUIREMENTS
!
Blue = neutral
Brown = hot
Yell ow /gr e en =
earth ground
(chassis
!
!
The maximum number of loudspeakers that can be looped
from the Loop Output connector is determined by the voltage of the power source, the circuit breaker rating, and the
rating of the AC power cable connected to the first JM-1P
loudspeaker.
Number of JM-1Ps that Can Be Looped with AC Power
Circuit Breaker/
Connector Rating
15 amps 2 looped
20 amps 3 looped
115 V AC 230 V AC 100 V AC
(3 total)
(4 total)
5 looped
(6 total)
7 looped
(8 total)
1 looped
(2 total)
2 looped
(3 total)
Each JM-1P loudspeaker ships with one AC looping connector for making AC looping cables. Assembled AC looping cables are available from Meyer Sound (15-inch UL AC
looping cable, PN 28.115.032.01; 0.35 m CE AC looping
cable, PN 28.115.032.02).
CAUTION: Do not exceed the current capabil-
ity of the 20-amp Input connector for the
JM-1P loudspeakers. When looping loudspeakers,
consider the total current draw for all loudspeakers
on the circuit, including the first loudspeaker.
When wiring international or special-purpose power connectors:
Connect the blue wire to the black terminal, or the termi-
nal marked with an N.
Connect the brown wire to the red terminal, or the termi-
nal marked with an L.
Connect the yellow and green wire to the green (or green
and yellow) terminal, or the terminal marked with an E.
CAUTION: When creating AC power cables
and distribution systems, it is important to preserve AC line polarity and connect the earth ground
on both ends of the cable. The JM-1P requires a
grounded connection. Always use a grounded outlet
and plug. It is extremely important that the system be
properly grounded in order to operate safely and
properly. Do not ground-lift the AC cable.
JM-1P VOLTAGE REQUIREMENTS
The JM-1P operates safely and continuously when the AC
voltage stays within 95–125 V AC and 208–235 V AC at 50
or 60 Hz. The JM-1P allows any combination of voltage to
GND (neutral-line-ground or line-line-ground).
AC Connections with VEAM Cabling
The JM-1P can be ordered from the factory with a VEAM allin-one connector. VEAM connectors consolidate AC power,
audio, and RMS into a single cable, facilitating easy connections and quick setups. For more information, see
Appendix A, “Optional VEAM Multipin Connector.”
POWER CONNECTOR WIRING
The JM-1P requires a grounded outlet. To operate safely
and effectively, it is extremely important that the entire system be properly grounded.
AC Cable Wiring Scheme
If the voltage drops below 85 V (brownout), the JM-1P uses
stored power to continue operating temporarily; the loudspeaker will shut down if the voltage does not rise above the
low boundary before the stored power is used.
If the voltage rises above 235 V, the power supply could
become damaged.
CAUTION: The power source for the JM-1P
should always operate within the required voltage range, at least a few volts from the upper and
lower ranges. This will ensure that AC voltage variations from the service entry — or peak voltage drops
due to cable runs — will not cause the loudspeaker’s
amplifiers to cycle on and off or cause damage to the
power supply.
Powering Up the JM-1P
When AC power is applied to the JM-1P, its Intelligent AC™
power supply automatically selects the correct operating
voltage, allowing it to be used internationally without manually setting voltage switches. In addition, Intelligent AC also
suppresses high-voltage transients up to several kilovolts,
filters common mode and differential mode radio frequencies (EMI), and sustains operation temporarily during lowvoltage periods.
10
JM-1P OPERATING INSTRUCTIONS
!
!
When powering up the JM-1P, the following startup events
take place over several seconds.
1. Audio output is muted.
2. Voltage is detected and the power supply mode is automatically adjusted as necessary.
3. The power supply ramps up.
4. The green On/Temp LED on the user panel lights up,
indicating the loudspeaker is ready to output audio.
NOTE: The fan remains off at turn-on. It is con-
trolled by audio level and operates only at high
audio levels.
CAUTION: If the On/Temp LED does not light
up, or the loudspeaker does not output audio
after ten seconds, remove AC power immediately
and verify that the voltage is within the required
range. If the problem persists, contact Meyer Sound
Technical Support.
CAUTION: If either of the loudspeaker’s circuit
breakers trip (the white center buttons disengage), make sure to disconnect the AC power cable
before resetting the breakers. If necessary, contact
Meyer Sound for repair information.
JM-1P CURRENT REQUIREMENTS
The current draw for the JM-1P is dynamic and fluctuates as
operating levels change. Since different cables and circuit
breakers heat up at varying rates, it is important to understand the following types of current ratings and how they
affect circuit breaker and cable specifications.
Idle Current — The maximum rms current during idle
periods.
Maximum Long-Term Continuous Current — The
maximum rms current during a period of at least 10 seconds. The Maximum Long-Term Continuous Current is
used to calculate temperature increases for cables, to
ensure that cable sizes and gauges conform to electrical
code standards. The current rating is also used as a rating for slow-reacting thermal breakers. In addition, the
Maximum Long-Term Continuous Current can be used to
calculate the AC looping capability of the JM-1P.
Burst Current — The maximum rms current during a
period of around one second. The Burst Current is used
as a rating for magnetic breakers. It is also used for calculating the peak voltage drop in long AC cable runs
according to the following formula:
V pk (drop) = I pk x R (cable total)
Ultimate Short-Term Peak Current — A rating for fast-
reacting magnetic breakers.
Inrush Current — The spike of initial current encoun-
tered when powering on.
You can use the following table as a guide for selecting
cable gauges and circuit breaker ratings for the system’s
operating voltage.
JM-1P Current Draw
Current Draw 115 V AC 230 V AC 100 V AC
Idle Current 0.50 A rms 0.28 A rms 0.56 A rms
Maximum Long-Term
Continuous Current
Burst Current 8.0 A rms 4.1 A rms 9.2 A rms
Ultimate Short-Term
Peak Current
Inrush Current 7.1 A peak 8.4 A peak 7.1 A peak
4.55 A rms 2.50 A rms 5.25 A rms
20.8 A peak 13.0 A peak 21.6 A peak
The minimum electrical service amperage required by a
JM-1P loudspeaker system is the sum of the Maximum
Long-Term Continuous Current for each loudspeaker. An
additional 30 percent above the minimum amperage is recommended to prevent peak voltage drops at the service
entry.
NOTE: For best performance, the AC cable
voltage drop should not exceed 10 V, or
10 percent at 115 V and 5 percent at 230 V. Make
sure that even with AC voltage drops that the AC
voltage always remains within the operating windows.
11
CHAPTER 2: POWER REQUIREMENTS
Earth ground
Chassis ground
ELECTRICAL SAFETY ISSUES
Pay close attention to these important electrical and safety
issues.
The JM-1P requires a grounded outlet. Always use a
grounded outlet and plug.
Do not use a ground-lifting adapter or cut the AC cable
ground pin.
Do not exceed the current capability of the 20-amp AC
Input connector for the loudspeaker. When looping loudspeakers, consider the total current draw for all loudspeakers on the circuit, including the first loudspeaker.
Make sure the AC power cable for the loudspeaker has
the appropriate power plug (on the other end) for the
area in which you will operate the loudspeaker. In addition, the AC power cable must be rated for the total current draw of all loudspeakers looped from the power
source.
Do not operate the unit if the power cables are frayed or
broken.
Keep all liquids away from the JM-1P to avoid hazards
from electrical shock.
12
CHAPTER 3: AMPLIFICATION AND AUDIO
The JM-1P low- and high-frequency drivers are powered by
a proprietary two-channel Meyer Sound amplifier with
MOSFET output stages. The audio signal is processed with
an electronic crossover, correction filters for phase and frequency response, and driver protection circuitry. Each channel has peak and rms limiters that prevent driver overexcursion and regulate the temperature of the voice coil.
The user panel on the back of the JM-1P has two slots for
modules. The top slot contains an audio input module
(described in this chapter). The bottom slot is reserved for
the optional RMS module, used for connecting to the RMS
remote monitoring system (see Chapter 6, “The RMS
Remote Monitoring System”).
VEAM CABLING
The JM-1P can be ordered from the factory with a VEAM allin-one connector. VEAM connectors consolidate AC power,
audio, and RMS into a single cable, facilitating easy connections and quick setups. For more information, see
Appendix A, “Optional VEAM Multipin Connector.”
THE LOOPING AUDIO INPUT MODULE
The Looping Audio Input module includes input and looping
connectors, and LEDs for monitoring temperature and limiting.
Input Connector
The female XLR Input connector accepts a balanced audio
signal with an input impedance of 10 kOhm. The connector
uses the following wiring:
Pin 1 — 220 kOhm to chassis and earth ground (ESD
clamped)
Pin 2 — Signal (+)
Pin 3 — Signal (–)
Case — Earth (AC) ground and chassis
Pins 2 and 3 carry the input as a differential signal. Pin 1 is
connected to earth through a 220 kOhm, 1000 pF, 15 V
clamped network. This circuitry provides virtual ground lift
for audio frequencies while allowing unwanted signals to
bleed to ground. Make sure to use standard, balanced XLR
audio cables with all three pins connected on both ends.
Telescopic grounding is not recommended, and shorting an
input connector pin to the case may cause a ground loop,
resulting in hum.
TIP: If unwanted noise or hiss is produced by
the loudspeaker, disconnect its input cable. If
the noise stops, there is most likely nothing wrong
with the loudspeaker. To locate the source of the
noise, check the audio cable, source audio, and AC
power.
Looping Audio Input Module
Loop Connector
The male XLR Loop connector allows multiple JM-1P loudspeakers to be looped from a single audio source. Connect
the Loop output of the first loudspeaker to the Input of the
second, and so forth. The Loop connector is wired in parallel
to the Input connector and transmits the unbuffered source
signal even when the loudspeaker is powered off.
To avoid distortion when looping multiple JM-1P loudspeakers, make sure the source device can drive the total load
impedance of the looped loudspeakers. In addition, the
source device must be capable of delivering 20 dBV
(10 V rms into 600 ohms) to yield the maximum peak SPL
over the operating bandwidth of the loudspeaker.
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CHAPTER 3: AMPLIFICATION AND AUDIO
High-frequency limiter LED
Low-frequency limiter LED
!
To calculate the load impedance for the looped loudspeakers, divide 10 kOhms (the input impedance for a single
JM-1P) by the number of looped loudspeakers. For example, the load impedance for 10 JM-1P loudspeakers is
1000 ohms (10 kOhms / 10). To drive this number of looped
loudspeakers, the source device should have an output
impedance of 100 ohms or less. This same rule applies
when looping JM-1P loudspeakers with other self-powered
Meyer Sound loudspeakers and subwoofers.
NOTE: Most source devices are capable of
driving loads no smaller than 10 times their
output impedance.
NOTE: Make sure that all cabling for looped
loudspeakers is wired correctly (Pin 1 to Pin 1,
Pin 2 to Pin 2, and so forth) to prevent the polarity
from being reversed. If one or more loudspeakers in a
system have reversed polarity, frequency response
and coverage can be significantly degraded.
Limit LEDs
The low- and high-frequency drivers for the JM-1P are powered by separate amplifier channels, each with their own
limiter. Limiting activity is indicated with the two yellow Limit
LEDs. The top LED indicates limiting for the high-frequency
channel and the bottom LED indicates limiting for the lowfrequency channel. When engaged, a channel’s limiter not
only protects the driver, but also prevents signal peaks from
causing excessive distortion in the amplifier’s channel,
thereby preserving headroom and maintaining smooth frequency responses at high levels. When a channel’s level
returns to normal, below the limiter’s threshold, limiting
ceases.
The JM-1P performs within its acoustical specifications at
normal temperatures when the Limit LEDs are unlit, or if the
LEDs are lit for two seconds or less and then turn off for at
least one second. If an LED remains lit for longer than three
seconds, that channel enters hard limiting where:
Increases to the input level have no effect.
Distortion increases due to clipping and nonlinear driver
operation.
The driver is subjected to excessive heat and excursion,
which will compromise its life span and may eventually
lead to damage over time.
CAUTION: The Limit LEDs indicate when a
safe, optimum level is exceeded. If a JM-1P
loudspeaker begins to limit before reaching the
required SPL, consider adding more loudspeakers to
the system.
NOTE: The JM-1P loudspeaker uses optical
limiters that add no noise and have no effect
on the signal when the limiters are not engaged and
the Limit LEDs are not lit.
On/Temp LED
When the JM-1P is powered on, its On/Temp LED turns
green. If the temperature of the heat sink reaches 85° C
(185° F), the On/Temp LED changes from green to red and
the limiter threshold is lowered to a safe level to prevent the
system from overheating. Under high temperature conditions the output level is reduced by approximately 6 dB.
When the heat sink temperature decreases to 80° C
(176° F), the On/Temp LED changes from red back to green
and the limiter threshold returns to normal.
Limit LEDs
14
NOTE: When the On/Temp LED is red, this is
an indication that the unit is reaching its maximum dissipation and a reduction in SPL is recommended.
TIP: When the JM-1P is connected to an RMS
network, the RMS software provides additional
feedback on the loudspeaker’s operating temperature. For more information, see Chapter 6, “The RMS
Remote Monitoring System.”
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