EM Acoustics EMS-51 User manual

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EMS-51 User Manual
www.emacoustics.co.uk
EMS-51 Compact Fill Loudspeaker
User Manual –v1.0
EM Acoustics Loudspeakers
Building 74, Dunsfold Park
Cranleigh, Surrey
GU6 8TB, UK
Phone [phone]
Fax [phone]
www.emacoustics.co.uk
_________________________________________________________________________________________
Copyright EM Acoustics 2012

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CONTENTS
Introduction
Thank you ...……………………………………………………………………………………………………………………………. 3
Unpacking ……………………………………………………………………………………………………………………………….. 3
Declaration of Conformity …………………….…………………………………………………………………………………… 3
Product Overview
EMS-51 passive two-way fill enclosure .........……………………………………………………………………………… 4
System Set-up
Safety Considerations………………………………………………………………………………………………………………… 5
Cabling & Amplifier selection ……………………………………………………………………………………………………… 6
Protective DSP Settings ................................................................................................................. 7
Mounting & Rigging Options
Rigging Hardware & Accessories ………………………………………………………………………………………………… 8
Permanent Installations …………………………………………………………………………………………………………….. 8
Flying Yoke Use...............……………………………….…………………………………………………………………………. 9
Maintenance
EMS-51 Drive Unit Service ………………………………………………………………………………………………………….10
Warranty ……………………………………………………………………………………………………………………………………………. 11
Appendix A –Technical Specifications …………………………………………………………………………………………………… 12

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INTRODUCTION
Thank you
Thank you for purchasing a product from the acclaimed EMS Series from EM Acoustics. The EMS Series products
have been carefully designed and rigorously tested to ensure years of flawless operation and unprecedented sonic
quality. Flexibility is the key factor with EMS products, and consequently they are at home within a wide variety of
applications from live and portable applications, through to cafes, bars, nightclubs, theatres and conference
centres.
Please ensure that you read this manual carefully before use, and that you keep it to hand should you need it for
further reference. Furthermore, should you have any difficulties please do not hesitate in contacting your EM
Acoustics dealer, or email [email protected]o.uk for further assistance.
Unpacking
Every EM Acoustics product is built to the highest standard and thoroughly tested before it leaves our factory.
After unpacking your loudspeaker, please inspect it carefully for any signs of transit damage. If such damage is
found, please notify the carrier at once to instigate a claim. It is suggested that you retain all packaging for future
re-shipment.
DECLARATION OF CONFORMITY
The products contained within this manual conform to the requirements of the EMC
Directive 89/336/EEC, amended by 92/31/EEC and to 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
RECYCLING
This product and its packaging constitute the applicable product according to the WEEE directive.
Please ensure that at the end of the working life of this product, it is disposed of sensibly in
accordance with local and national recycling regulations. The packaging supplied with this product
is recyclable. Please retain all packaging, however if disposing of this packaging please ensure
that you comply with local recycling regulations. These products also all comply to the RoHS
Directive 2002/95/EC.

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PRODUCT OVERVIEW
EMS-51 compact fill loudspeaker
The EMS-51 is a compact, versatile, fill loudspeaker product designed for a wide variety of compact and discreet
sound reinforcement applications. It features a high-power 5” (127mm) LF drive unit in an infinite baffle
enclosure, and a 1.1” (28mm) soft dome high frequency drive unit. These components are matched by an internal
passive crossover network for unprecedented sonic quality from a completely passive enclosure.
Due to its discreet size and appearance, and the included YK-51v and YK-51h mounting yokes, the EMS-51 can be
used in a wide variety of applications.
As with all EM Acoustics full-range products, no active controller or programmed EQ is required for correct
operation. For demanding applications, an 80Hz, 24dB/octave high pass filter is recommended to increase drive
unit headroom however this is not essential for normal operation –please see page 7 for further information.
The EMS-51 is supplied as standard in black or white, and is fitted with two Neutrik SpeakONTM NL4MP connectors.
Custom colours and weather protection can also be supplied if required –please contact your local EM Acoustics
representative for more details.

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SYSTEM SET-UP
Safety Considerations
Loudspeaker systems are potentially dangerous objects if used incorrectly. Please ensure that you read this
section fully, and contact EM Acoustics or your local dealer should you be in any doubt over correct operation
procedures.
Professional loudspeaker systems are capable of producing damage-inducing sound pressure levels, and hence
care should be taken when setting your system up, particularly when it comes to loudspeaker placement within a
venue. Damage to the ear can result from levels above 90dB under prolonged exposure.
Stand Mounting
The EMS-51 can be mounted from a microphone stand when using the supplied yokes, or the PM-61 adapter for a
standard 35mm loudspeaker stand. When mounting in this way, please consider the following:
Ensure your stand height is locked off and the tripod legs are positioned so as to be stable.
Check the weight loading of your stands before attempting to mount the loudspeaker.
Do not stack a second loudspeaker on top of the stand-mounted one.
Ensure cables are run so as to leave enough slack to enable neat wiring, and thus reduce the risk of the
speaker being pulled over. Loose cables should be covered or taped down wherever possible to reduce trip
hazards.
If stands are being used outdoors, it may be necessary to add ballast to the base of the stand to prevent it
toppling over.
When using poles on top of subwoofer systems, please observe similar precautions.
Ground Stacking
Ensure that the floor or stage surface can withstand the weight of the system.
Wherever possible, avoid high stacks and use ratchet straps to secure loudspeakers together. Please also
remember that vibrations from subwoofer systems can shake other loudspeakers out of place, which may
present a toppling hazard. The use of ratchet straps and non-slip material is recommended to prevent this.
Rigging and Suspension
There are a variety of different methods for suspending your EMS-51 enclosures –please see the detailed section
on Page 8 for further information.
WARNING: The overhead suspension of loudspeakers is a very serious issue with potentially lethal
consequences should anything go wrong. Rigging should only be carried out by experienced

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personnel following safe working practice. Should you be in any doubt whatsoever, please contact
your local dealer who will be able to refer you to a suitable rigging company.
Cabling and Amplifier Selection
The EMS-51 is designed to be used with professional power amplifiers providing the following power outputs:
EMS-51 400W/channel into eight ohms
It is good practice to use an amplifier equal to the program power rating of the loudspeaker –so as to retain
sufficient headroom and good dynamic range. Care should be taken during operation to avoid amplifier clipping –
as this can cause serious damage to your loudspeakers. If in doubt, please contact your dealer who will be happy
to assist you in correct amplifier choice and setup.
Cabling
The EMS-51 is supplied as standard with Neutrik SpeakONTM NL4 connectors, wired pin 1+/1-. It is recommended
that the resistance of your cable is less than one tenth of the nominal system impedance. Given below are the
recommended maximum cable lengths for different cross-sections and impedances.
Conductor Cross Sectional Area Maximum Recommended Cable Length
4 ohms 8 ohms 16 ohms
1.0mm211m 22m 44m
1.5mm2 17m 34m 68m
2.0mm222m 44m 88m
2.5mm229m 58m 116m
4.0mm244m 88m 176m
6.0mm266m 132m 264m
Pins 2+/2- on the SpeakONTM connectors are wired together to allow link-through with 4-core cables.
A small power amplifier working too hard is more likely to damage a loudspeaker than a large power amplifier
working within its operating range!

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Protective DSP Settings
The EMS-51 requires no DSP program to function correctly. However, excessive low frequency information will
cause the LF drive unit’s excursion to increase, which can result in damage to your loudspeaker.
The higher you raise the high pass filter on an EMS-51, the more headroom and overall sound pressure level
output there is available. For most medium-to-high level applications, we would recommend a minimum of an
80Hz high pass filter with a 24dB/octave slope to sufficiently protect the loudspeaker. For higher SPL applications,
we would recommend raising this filter –we would stress that the higher the filter, the safer the loudspeaker will
be. If you are in any doubt over suitable settings for your EMS-51, please don’t hesitate to contact EM Acoustics
or your local dealer for support and advice.

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MOUNTING & RIGGING OPTIONS
Rigging Hardware & Accessories
The EMS-51 is supplied with the YK-51v and YK-51h flying yokes for mounting and suspension.
The EMS-51 contains four M8 threaded fixing points around the enclosure, to enable suspension using forged
shoulder eyebolts (minimum thread length 10mm) or the included YK-51v vertical or YK-51h horizontal flying
yokes. These fixings allow suspension in any orientation, with the unused points available for pull-back to obtain
the desired rigging angle or as a secondary safety point.
With any suspension method, a second anchor point should be used as a safety.
Under no circumstances should the mounting points of one enclosure be used to suspend another
enclosure below it. EM Acoustics are in no way responsible for the failure of incorrectly rigged
systems. This information relates specifically to the rigging techniques for the EMS-51 enclosures
only. If you are in any doubt about safe practices for rigging loudspeakers, please contact your local
EM Acoustics dealer who will be able to advise you.
Permanent Installations
Any installation (permanent or temporary) must be securely attached to the structure of the building using chain,
steel wire or web straps that are certified and load rated for the loudspeaker system. Consideration must be taken
when determining the loading on the structure to include loudspeakers and rigging hardware, and the appropriate
safety factor can then be decided upon. If you are in any doubt whatsoever, please contact your EM
Acoustics dealer who will be able to refer you to an experienced rigging company. A reputable rigging organisation
should also be able to advise on legislation regarding safety factors for suspended systems of this type.
Safety Considerations
When utilising any suspension method, a secondary safety must be used. For any suspension method, fit an M8
eyebolt to any of the unused rigging points. A safety steel can then be attached to this and connected to your
safety point. If you are in any doubt whatsoever about how to safely suspend your loudspeakers, do
not hesitate to contact your EM Acoustics representative who will be able to refer you to a qualified
rigging company for advice.

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Attachment of the YK-51v or YK-51h flying yokes
The YK-51v and YK-51h flying yokes both attach in the same way. Using the supplied M8 hand knobs, align the
mounting holes in the yoke with the mounting points on the enclosure. Ensure that the washers are also used
when fitting the bracket –the flat washer should be in contact with the yoke, and the spring washer will sit
between the flat washer and the locking knob.
Once the desired angle is set, tighten the knobs to lock the position in place.

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MAINTENANCE
Your EM Acoustics loudspeakers have been rigorously tested before they leave our factory, to ensure that they give
you a lifetime of flawless operation. Should any of your drive units fail and need replacing, please follow the
guidelines below.
EMS-51: Low Frequency Drive Unit
1. Using a #2 Phillips head screwdriver, undo the countersunk M4 screws top & bottom of the enclosure (1 each
end). Gently remove the grille from the front of the enclosure.
2. Using a 3mm Allen key, remove the four M4 socket-head bolts holding the drive unit in place, and keep them
safe –ensuring you have collected both the shake-proof and flat washers for each bolt. Gently lift the drive
unit out of its locating hole –please take care as it is heavy! Carefully disconnect the cables from the drive
unit.
3. To reinstate the driver, simply reverse the above procedure. Check the gasket on the driver chassis is
complete before installing it back into the enclosure. Please observe the correct polarity –red cable to positive
terminal, black cable to negative.
4. Reinstate the grille by gently placing it in place over the front of the loudspeaker. Replace the two
countersunk M4 machine screws to secure it in place.
EMS-51: High Frequency Drive Unit
1. Follow the procedure above to remove the front grille.
2. Using a #1 Pozidrive screwdriver, remove the three screws securing the drive unit in place. Gently disconnect
the cables from the drive unit and remove the unit from the enclosure.
3. To reinstate the drive unit, gently reconnect the cables (white cable to positive terminal, yellow cable to
negative) and insert back into position. Ensure that the insulation on the crimp connectors is covering the
terminal itself. Note that the terminals fit into the recess in the enclosure towards the bottom of the
loudspeaker. Also ensure the gasket is complete around the drive unit before tightening the screws.
4. Reinstate the grille by gently placing it in place over the front of the loudspeaker. Replace the two
countersunk M4 machine screws to secure it in place.

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WARRANTY
Limited Warranty
This EM Acoustics loudspeaker product is warranted to the original end-user purchaser and all subsequent owners
for a period of three years from the original date of purchase.
Warranty Coverage
This warranty covers defects in materials and workmanship. It does not include:
Damage or failure caused by accident, misuse, neglect, abuse or modification by any person other than an
authorised EM Acoustics representative.
Damage or failure caused by operating the loudspeaker product contrary to the instructions contained within
this manual.
Damage caused during shipment.
Claims based on any misrepresentation by the seller.
Products which contain anything other than the original components (or EM Acoustics factory supplied spare
parts).
Products on which the serial number has been removed, altered or defaced.
Returning your EM Acoustics loudspeaker
Should your EM Acoustics loudspeaker develop a fault, please return it (freight prepaid) in its original packaging,
along with proof of purchase to your local dealer or to:
EM Acoustics (Returns Department), Building 74, Dunsfold Park, Cranleigh, Surrey, GU6 8TB, UK
including a description of the suspected fault. Serial numbers must be quoted in all correspondence relating to the
claim. EM Acoustics or its representatives are in no way liable for any loss or damage in transit, and hence it is
recommended that the sender insure the shipment. EM Acoustics will pay for return freight should the repair be
covered under warranty.
EM Acoustics’ liability is to the replacement or repair (at our discretion) of any defective components, and as such
are not liable for any incidental and consequential damages including (without limitation) injury to persons,
damage to property or loss of use.
This warranty is exclusive and no other warranty is expressed or implied. This warranty is also in
addition to –and in no way detracts from –your statutory rights as a consumer.

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APPENDIX A –TECHNICAL SPECIFICATIONS
EM Acoustics operates a continuous process of research and development, and as such reserves the right to alter specifications without notice.
EMS-51
ENCLOSURE TYPE: two-way passive, infinite baffle
DIMENSIONS (HxWxD): 250 (9.9) x 140 (5.5) x 175 (6.9) mm/(ins)
NET/SHIPPING WEIGHT: 4.5/5.2kg (9.9/11.7lbs)
FREQUENCY RESPONSE1:80Hz –20kHz +/- 3dB
SENSITIVITY2:89dB
DISPERSION3:75 conical
DRIVE UNITS: 5”(127mm) LF cone drive unit
1.1”(28mm) HF soft dome tweeter
POWER HANDLING: 200W RMS, 400W program
MAXIMUM SPL4: 113dB continuous, 119dB peak
NOMINAL IMPEDANCE: 8 ohms
CROSSOVER: asymmetric internal passive
CONNECTORS: 2 x Neutrik SpeakONTM NL4MP
ENCLOSURE: 12mm (1/2”) multi-laminate Birch plywood –rebated, pinned & glued.
Finished in impact resistant textured paint
RIGGING & HARDWARE: 4 x M8 threaded mounting points
GRILLE: perforated steel
OPTIONS: Colours/Weather Protection
ACCESSORIES: YK-51v vertical flying yoke
YK-51h horizontal flying yoke
SPARE PARTS: DU-501 5”drive unit
SD-1001 1.1”HF soft dome tweeter
PX-51 passive crossover assembly
RG-51 replacement grille
Notes on measurement conditions:
1Measured on-axis at 2m in an anechoic environment and referenced to 1m.
2Measured in half space at 2m with 4W sine wave input and referenced to 1m.
3Nominal dispersion, measured in an anechoic environment and averaged over stated bandwidth
4Calculated and verified by subjective listening test of familiar program material.