Opus Technologies LD Series User manual

EN
Installation and user
manual
LD 1.0 /2.0 /3.0
Class D loop amplifier
1-CHANNEL LOOP AMPLIFIER
LD SERIES

LD Series |Installation and user manual
User manual 2

3
TABLEOF CONTENTS|EN
1. Introduction 5
1.1 Purpose 5
1.2 Target audience 5
1.3 Alerts 5
1.4 Icons 5
2. Loop amplifier presentation 6
2.1 Description 6
2.2 The range 6
2.3 Package contents 6
2.4 Rack mounting kit: OP-R (optional) 6
2.5 Advice and safety 7
3. Technology presentation 8
3.1 What is an AFILS (Audio Frequency Induction Loop System) ? 8
3.2 Working principle 8
4. Controls, connections and adjustments 9
4.1 Control 9
4.2 Multi-loop output 9
4.3 Front panel and adjustments 10
4.4 Rear panel and adjustments 11
4.5 Rack mounting 12
4.6 Adjustment and connection 14
4.7 Connecting two amplifiers 16
5. Setup 18
5.1 Setting up a simple perimeter loop 18
5.2 Setting up a Master and a Slave amplifiers 18
5.3 Securing settings 19
5.4 Metal loss compensation adjustment 19
5.5 Operation of the fault contact 19
5.6 Audio input 19
6. Functioning and planning of a loop system 20
6.1 Preamble 20
6.2Working principle 20
6.3 The different types of installation. 21
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TABLEOF CONTENTS|EN
7. The magnetic induction loop 23
7.1 Installing your loop 23
7.2Cable section 23
7.3 Connection 23
7.4 The magnetic field 23
7.5 Technical study 24
8. Installation constraints 27
8.1 Magnetic overspill 27
8.2Metal distortion 27
9. Information 28
9.1 Maintenance and care 28
9.2 Warranty 28
9.3 After-sales service and return 28
9.4 Disposal of used electric and electronic units 28
9.5 Technical specifications 29
9.6 CE certification 30
Certificate of conformity to the IEC-60118-4 standard 31
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LD Series |Installation and user manual
User manual
1. Introduction
Thank you for having purchased an Opus Technologies
LD SERIES class Dloop amplifier.Please take afew
moments to read this manual, it will ensure the
optimal use of the product and many years of flawless
service.
1.1 Purpose
The installation and user manual provides the needed
informations to install,configure and to use your LD
Series amplifier.
1.2 Target audience
The installation and user manual is destined to Opus
Technologies’ LD Series amplifiers installers and
users.
1.3 Alerts
This manual mentions three types of warning.
The type of alert is closely related to the effect that
may occur if the alert is not observed.These alerts,
ranked in increasing order of severity, are as follows:
•Caution
Failure to follow acautionary warning may result in
property damage.
•Warning
Failure to heed awarning may result in serious
property damage and potential personal injury.
1.4 Icons
1.4.1 Note Icons
Warning icons used with the notes provide additional
information about the note.See the following
examples:
1.4.2 Caution, warning and danger icons
The icons used in combination with Caution, Warning
and Danger indicate the type of risk.See the
following examples:
Note:
General Note Icon
Note:
Symbol referring to the
indicated information source.
Caution, Warning, Danger:
Danger of electrocution icon
Caution, Warning, Danger:
General icon of caution, warning
and danger notices.
Caution, warning, danger:
Electrostatic discharge risk icon.

2. Loop amplifier presentation
2.1 Description
The LD range is composed of magnetic induction loop
amplifiers allowing to equip rooms for people
suffering from hearing loss.
The LD Series has been developed with strict and
rigorous specifications that allow us to offer a 5 year
warranty.The products have been designed with
options to facilitate their use and installation.
Product picture Figure1
The range of single channel amplifiers is composed of
the LD1.2, LD2.2 and LD3.2. They allow to cover
different surfaces as described below.
2.2 The product range
Opus Technologies' LD1.0, LD2.0 and LD3.0 are anew
generation of magnetic loop amplifiers, made in
France.These robust amplifiers are the most compact
on the market while offering the necessary features
(AGC, MLC, compressor, fault monitoring, etc.) to
ensure an installation in rooms from 100m² to
1000m².
•LD1.0 covers up to 250 m² -max width :10m
•LD2.0 covers up to 450 m² -max width :15m
•LD3.0 covers up to 1000 m² -max width :20m
These coverage informations are given on an
indicative basis and depend on the configuration of
the room and project constraints (presence of metal
structures, overspill, room width, etc). Not taking
these constraints may lead to an installation not
complying with the IEC-60118-4 standard
requirements.It is essential to consult aloop specialist
for your project design.Our Smartloop simulation
software will help you designing project complying
with the IEC-60118-4 norm.Contact your closest
distributor for more information.
2.3 Package contents
Upon reception of your amplifier, inspect the unit to
check if any damage have occurred during shipment.
If damages are noticed, report immediately to your
distributor and shipping company, indicating the
date of delivery, the nature of the damage, if it was
visible on the packaging before unpacking.If
possible, give the delivery note number and a
tracking number.
Package contents:
•LD1.0, LD2.0 or LD3.0 amplifier
•Power cable 1.5m, CEE 7/7 -C13 connectors
•2x 3-pin connectors
•1x 2-pin connector, output
•1x 2-pin connector, input
•A set of 3 stickers “Area adapted for the hard of
hearing people".
•Installation and user guide
•OP-R rack mounting kit (optional)
•Warranty certificate
If any pieces are missing, please contact your reseller
or the manufacturer directly.
2.4 Rack mounting kit: OP-R (optional)
OP-R contents
•2x rack mounting brackets
•2x mounting brackets
•8x mounting screws
Amplifier picture -Figure1
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User manual
LD Series |Installation and user manual
2.5 Advice and safety
Most of defective loop installations are the result of
alack of preparation.Take your time before starting
your installation
Ideally, the loop driver should be placed near the
area to be covered.This may involve placing the loop
driver on apanel/wall, under adesk or under a
counter.Wall mounting accessories are provided in
the OP-R mounting kit.
Refer to figure 9 on page 13
To chose the location for your loop, take into
consideration the area that would be most likely
used by the end user.This area is called the
“listening area”.
For exemple,in aconcert hall, you'll install your loop
cable around the audiance area rather than the
whole room.Covering also the stage may lead to
feedbacks effect due to aconflict between the loop
magnetic field and the dynamic microphones (guitar,
bass..)of the band playing on the stage
•To prevent accidents or personal injury caused by
electrical shocks, never place any type of
container filled with aliquid, such as avase, on or
around the device.
•Never pull on the power cord to remove the plug
from the wall outlet;always pull the plug.
•Do not operate the device near heat sources or in
rooms with high humidity.(Operating
temperature range 0-45°C).
•Do not cover the air vents so that any heat
generated by the device can be dissipated by air
circulation.
•Depending on the stress it is exposed to, the
device can develop high temperatures in the heat
sink and at the air vents. Be careful not to touch
these elements -risk of burns!
•An installation must be carried out by qualified
personnel.
•The device must be out of reach of unauthorized
persons.
•The device may only be operated by trained
staff qualified for loop installation.
•The device is intended to be used for inductive
loop systems only.
•To prevent potential injury, do not position
this device higher than 2meters from the
ground
•Connect the loop driver only to wiring which
complies to IEC-60364.

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Hearing aid operating diagram with the T-position -Figure 3
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User manual
3. Technology presentation
3.2 Working principle
Pictogram used to indicate a loop
system -Figure 2
Refer to figure 2
An induction loop system is intented to help hard of
hearing people to receive aclear audio signal into
their hearing aid without being disturb by
background noises .Thanks to this system, the
sound coming from an audio source (speaker
microphone, sound system, television) is transmitted
by induction to hearing aid user who can thus enjoy
clear sound without being disturbed by any ambient
noise.This system is mainly used in public places
(conference rooms, cinemas, courts, churches, ticket
offices, etc.) but can also be installed at home.Many
conventional hearing aids have a"T" loop function.
3.1 What is an AFILS (Audio Frequency
Induction Loop System)?
Amagnetic loop system consists of an electric wire
Layed down around aroom forming aloop.The
cable is connected to aloop amplifier, connected
itself to an audio source.The loop amplifier convert
the audio signal into electric pulses transmitted
through the cable, creating amagnetic field.Heairing
aids equipped with acoil (often called a"T" or "T-
coil". ) will capture this signal and transmit it to
hearing impared.
By induction, the electrical signal present in the loop
ill be reflected in the coil of the hearing aid.The coil
transmits the signal of the loop in the internal
amplifier of the prosthesis, which then bring it to the
ear of the hearing impaired person, free of
background noise and environmental disturbances.
The audio source can come from various origins.In a
cinema, for example, the sound of the film will be
transmitted.In aconference room, the sound of the
speaker's microphone will be transmitted.In a
subway station, the voice of the agent will be
transmitted...
The loop can be installed on the floor or ceiling.The
loop is integrated into the building, just like the
electrical installation.
The presence of ahearing loop is often indicated by
ablue logo representing abarred ear and the letter
"T".

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4. Controls, connections and adjustments
4.1 Control
The amplifiers comes with afault synthesis allowing
you to monitor the main functions of the unit, such
as the amplifier’s power, the integrity of the loop
cable connected to the amplifier and the inputs.
If any of the functions are faulty and not working
properly, ared LED on the front panel of the
amplifier lights up and the fault relay opens (NO:
Normally Open).
4.2 Multi-loop output
The LD1.0, LD2.0 and LD3.0 amplifiers have two OUT
0° and 90°outputs and one IN input on the rear
panel (see Figure 5on page 11). This feature offers
the possibility of combining several amplifiers
together.
Depending on the layout of the loops, the aim is to
control the external overspill of the magnetic field
and/or the homogeneity of coverage or the coverage
area.
Refer to section Layout page –24
For more information on the installation of aloop
using amaster loop and a90°phased shifted slave
loop, contact your local distributor, contact your local
distributor.
You can also use our Opus Smartloop simulation
software or contact us at
[e-mail].
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4.3Front panel and adjustments
Front panel - Figure4
1. "Protect" LED, fault summary display.Error indicator.This red LED lights up when the master loop amplifier is
overloaded, when the input level of the master loop is too high or when the master loop is defective.
2. “Loop" LED, loop presence.This green LED is displayed when the loop is in working condition.
3. Output current adjustment.Allows you to control the electrical output current distributed in the loop.
4. INPUT 3 (100V) input adjustment.This controls the signal of the INPUT 3.
5. INPUT 2(line or microphone) input adjustment.Allows to control the signal of the INPUT 2.
6. INPUT 1(line or microphone) input adjustment.Allows to control the signal of the INPUT 1.
7. ON/OFF power push button.
8. “Clip" LED, amplifier saturation display.Error indicator.This red LED lights up when the Slave loop amplifier is
overloaded, when the input level of the Slave loop is too high or when the Slave loop is faulty.
9. “Power" LED, ON/OFF display.Power on indicator light.
10. Input signal meter.Indicates the input signal level after adjustment.
11. Output signal meter.Indicates the electrical current in the induction loop.
12. MLC (Metal Loss Compensation) setting reduces interference problems due to the presence of metal
structures.
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4.4Rear panel and adjustments
11
13. INPUT 3Combo audio input:microphone or line.This input allows you to connect external audio inputs from a
line level source (mixer, pre-amp, etc.) or from amicrophone.The Combo connector accepts an XLR or a 6.35 jack.
14. Push button for line or microphone communication of the INPUT 1input.Switch to commute the input
according to the source (microphone or line).
15. Push button for line or microphone communication of the INPUT 2input.Switch allowing to commute the input
according to the source (microphone or line).
16. INPUT 2Phoenix type terminal block:microphone or line.This terminal block input is used to connect external
audio inputs from aline level source (mixer, preamp, etc.) or from amicrophone.
17. INPUT 1Phoenix type terminal block:100Vpriority.This terminal block input allows you to connect an external
audio input from a100Vsound system, the audio is directly recovered from the speaker’s line.
18. Slave IN input.This input is used to connect a 0° or 90°output (Master/Slave) from another LD series loop
amplifier.
19. 0° or 90°OUT output to slave amplifier.These outputs are used to connect the Master amplifier to aSlave loop
amplifier from the LD range.
20. Location of the serial number label.
21. Mains power cord connection.Connects the loop amplifier to the power supply.
22. Phantom power selection switch.Allows you to send or not voltage to supply amicrophone connected to INPUT
1and/or INPUT 2.
23. NO/NC fault relay.Allows the system status information to be sent via arelay.
24. Loop output on Phoenix type terminal block.Allows to connect the loop wire to the amplifier.
Rear panel - Figure5
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4.5 Rack mounting
4.5.1 Ventilation and rack mounting
For better ventilation we recommend leaving aspace
of 1U (44 mm) above the amplifier.
Leave at least 168 mm (5.5") of space between the
bottom of the rack and the amplifier.
Caution, warning, danger:
The LD1.0, LD2.0, LD3.0 amplifiers contain
an advanced protection circuit, which
allows them to reduce the output power
4.5.2 Rack integration
Required accessory: OP-R* mounting kit
Attach the rack mounting brackets as shown below
(Figure 7) using the mounting screws provided in the kit.
Then integrate the amplifier into the rack.
Amplifier ventilation- Figure 6
Illustration of the
amplifier integration in
a rack -Figure 7
to maintain safe operating temperatures.Insufficient
ventilation may cause areduction of the amplifier’s
output power during normal operation (indicated by
illumination of the red CLIP/PROTECT LEDs).To
reduce the risk of thermal limitation and allow
proper heat dissipation, it is recommended to keep
clear the space directly above and behind these
amplifiers.It is also highly recommended not to place
anything directly on top of the amplifier.
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*The OP-R mounting kit is not supplied with the
one-channel amplifiers (LD1.0, LD2.0 and LD3.0)
of the LD series.

*The OP-R mounting kit is not supplied with the
one-channel amplifiers (LD1.0, LD2.0 and LD3.0)
of the LD series.
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4.5.4Mounting the loop amplifier on a wall
Attach the mounting brackets as shown below (Figure 9)
using the screws provided in the kit.
Then, attach the amplifier to the selected wall.
Illustration of 2 amplifiers integrated
in a rack -Figure 8 Illustration of an amplifier integration
on a wall -Figure 9
Note:The OP-R mounting kit is not supplied with the
one-channel amplifiers (LD1.0, LD2.0 and LD3.0) of the
LD series.
4.5.3 Rack-mounting two loop amplifiers
Required accessory: OP-R* mounting kit
Attach the rack mounting brackets as shown below
(Figure 8) using the mounting screws provided in the kit.
Then attach the amplifiers to each other with the
mounting brackets.
Finally, integrate the amplifier into the rack.
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Required accessory: OP-R* mounting kit

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4.6 Adjustment and connection
4.6.1 Loop connection
The loop is connected via agreen 2-point terminal
block located on the rear panel of the amplifier,
thanks to atwisted cable.
Distance between the loop and the
amplifier must not exceed 15 m.
The twisted cable cancels the magnetic
field and avoids inductions potentially created by
transformers external to the system. The references
OP-LI5/10 or 15 allow to create this type of
connection.
4.6.2 Audio inputs
The audio sources are connected via the 3inputs
of the amplifier provided for this purpose.The
LD Series have 3inputs:
•Input 1: 100 V
•Input 2: lines or microphones
•Input 3: lines or microphones
The loop circuit must use cabling conforming to the
IEC-60332-1-2, 60332-1-3, 60332-2-1, 60332-2-2 or
60695-11-21 standards.
4.6.3 Priority INPUT 1 100V input
The INPUT 1 (100V) of the LD series amplifiers has a
priority for security sound systems in case of
evacuation of the building.
If more than one audio source reaches the
amplifier's inputs, the priority input will always have
priority over the others, and the INPUT 2and/or
INPUT 3will be muted.In some cases, and if the
configuration allows it, we recommend connecting
the room sound system to INPUT 2and INPUT 3and
the security sound system to INPUT 1.
4.6.4 Input and outputs jack 6.35
4.6.5 Line output
It is possible to connect arecorder to the line output
of the loop amplifier.The line output of the amplifier
is a 6.35 OUT 0° jack which is mainly used to link
several amplifiers when setting up complex systems
(low spill system) but the output can also be used as a
single line output.
4.6.6 Power supply
The LD amplifiers have an integrated power supply of
230V(or 115V), with apower of 300VA.
4.6.7 Status relay
The status output is used to send astatus of the loop
amplifier to external devices via aNO/NC relay.
4.6.8 Connectors
Symmetric:
Pin 1 :
Pin 2 :
Pin 3 :
Mass/Ground/ Schield
Hot spot (+)
Cold spot(-)
Asymmetric:
Pin 1 :
Pin 2 :
Pin 3 :
Mass/Ground
Signal (+)
Connected to mass (pin 1)
3 pin-XLR
PUSH
2 1
3
Hot spot Cold spot Mass
6.35 mm jack
On the rear panel of the amplifier you can see three
6.35 jack inputs.These inputs and outputs allow you
to connect several loop amplifiers together to create
single phased loop systems, low loss systems or ultra
low loss systems.
Refer to the types of connection in paragraph 4.7 and
the different types of installation in paragraph 6.
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4.6 Adjustment and connection
4.6.9 Switching on
Loop
Protect
Clip
Power
Loop
Protect
Clip
Power
Loop
Protect
Clip
Power
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4.6.11 Protect and Clip LEDs
The "Protect "and "Clip "LEDs light up if :
•The ohmic resistance of the inductive loop is
not between 0.5 and 3Ohm.
•The corresponding conductor section is
overloaded or overheated.
•The input level is too high, causing clipping of
the audio signal.
The unit is powered up using the grey switch on the
front of the amplifier.If the amplifier is powered up
the Power LED will light up in blue.
To turn the unit off, press again the Power switch on
the front of the amplifier again.Please note that the
unit goes into standby mode when it is turned off.
Unplug the power plug from the wall outlet to
completely turn off the unit.
4.6.10 Loop integrity
The green LED on the front of the amplifier is used to
check the loop integrity.If the loop is cut or if the
loop impedance is not between 0.5 and 3Ohm the
Loop LED will not be displayed and the Protect LED
will be light up.(See figure below)
×Loop fault, input too high and/or
amplifier overloaded
Loop OK
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4.7Connecting two amplifiers
4.7.1 Master over 1 Slave
To expand and duplicate an installation or to use alow spill system or high coverage system with the LD Series
1-channel amplifiers:
1. Connect the loops to the terminals provided:amplifier Loop terminal.
2. Insert an audio source into INPUT 1, 2 or 3of the master amplifier.
3. Connect the OUT 90°output of the Master amplifier to the Slave amplifier using a 6.35mm link cable.
4. Turn on the amplifiers and adjust them accordingly.
4.7.2 Slave to slave
Connect the OUT jack (0° or 90°) of the slave loop amplifier to the IN jack of the next slave loop amplifier.
This allows you to connect several slave amplifiers.(See diagram on next page)
This allows you to use multiple amplifiers on the same input.This can be useful for very large rooms or if several
rooms share the same audio transmission.
90°output to Slave
amplifier
OUT
16
Master amplifier Slave amplifier
Input on slave amplifier
IN
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4.7.2 Master to several slaves
90°output to
amplifier Slave
17
OUT
Master amplifier Slave 1 amplifier
Input on slave 1
amplifier
IN
and 0°output to slave
amplifier
OUT
Input on slave 2
amplifier
IN
and 90°output to slave
amplifier
OUT
Slave 2 amplifier Slave 3 amplifier
Input on slave 3
amplifier
IN
and 0°output to slave
amplifier
OUT
Slave 4 amplifier
Input on amplifier Slave 4
IN
To use a low spill or very high coverage system:
1. Connect the OUT 90°jack of the master loop amplifier to the IN jack of the next slave loop amplifier (Slave
Amplifier 1).
2. Connect the OUT 0°socket of amplifier 1 to the IN socket of the next amplifier (unit 2).
3. Connect the OUT 90°socket of amplifier 2 to the IN socket of the next amplifier (unit 3).
4. Connect the OUT 0°socket of amplifier 3 to the IN socket of the next amplifier (unit 4).
5. Repeat if necessary.
6. Connect the respective out-of-phase loops to the terminal blocks of the corresponding amplifiers.
7. Switch on the amplifiers and adjust them accordingly.
This type of configuration will be used to cover large areas such as those of exhibition parks or sports halls or to
equip several areas with the same audio source.
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5. Setup
5.1 Setting up a simple perimeter loop
1. Turn on your amplifier and check that all the
potentiometers are at 0level
2. Connect your loop to the Loop 1terminal block
3. Connect a 1kHz sinusoidal source to one of the
inputs
4. Increase the input signal via the potentiometer on
the front of the amplifier until you reach between
-6 and 0dB.
5. Increase the output current via the Loop 1
potentiometer on the front panel of the amplifier
until you reach between 75%and 85%.
6. Take amagnetic field meter such as OP-FSM* and
make afirst measurement at the center of your
room.
7. Then readjust the settings until you reach -3dB at
the center of the zone
8. Then follow the test procedure described in the
OP-FSM manual for an installation that meets the
IEC-60118-4 standard.
5.2 Setting up a Master and a Slave amplifiers
5.2.1 Master loop amplifier
To know the different types of implementation of a
low spill loop system or single phased loops, refer to
paragraphs 6.3.2 and 6.3.3.
Depending on the type of LD series amplifier, the
settings will be different:
•LD1.0/2.0/3.0 series units (not covered in this user
manual) incorporate one amplifier per unit so
you’ll need two devices to process aphase shift
Installation
•LD1.2/2.2/3.2 series incorporate two amplifier in
one unit allowing you to use only one device for
low spill systems. A second device will be required
whenever a 3rd loop is installed.
There is no special adjustment to determine the
Slave amplifier, only the connection arrangement
will define the Slave and Master amplifiers.
The Master amplifier is the unit to which the audio
signal at input 1, 2 or 3is connected.This will be
the basic signal.The phase shift module integrated
in the units will then shift this signal by 90°or 0° to
inject it into the next slave amplifier.
1. Power up your amplifier and check that all the
potentiometers are at 0
2. Connect your loop to the Loop1terminal block
3. Connect a 1kHz sinusoidal source to one of the
inputs
4. Increase the input signal via the potentiometer
on the front of the amplifier until you reach
between -6 and 0dB of the input meter
5. Increase the output current via the Loop 1
button on the front panel of the amplifier until
you reach between 75%and 85%.
6. Take amagnetic field mesurer such as OP-FSM
and make afirst measurement at the center of
your room
7. Then adjust the settings according to the
measurements made with your magnetic field
mesurer in order to achieve homogeneous
coverage in accordance with the IEC60118-4
standard.
5.2.2 Slave loop amplifier
8. Turn on your amplifier and check that all the
potentiometers are at 0level
9. Connect your loop to the Loop 1terminal
block
10. Connect the master amplifier via a 6.35mm
jack cable to the 6.35mm IN jack
11. Increase the output current via the Loop 1
button on the front panel of the amplifier
until you reach between 75%and 85%.
12. Take amagnetic field meter such as OP-FSM
and make afirst measurement at the center
of your room
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IN 3 IN 2
Phantom
19
Mic Line
If you detect signal distortion due to
presence of metal structure turn the
MLC (Metal Loss Compensation) control
on the front panel of the amplifier
clockwise.
Check your high frequency measurements with a 4kHz
sinusoidal signal and adjust the compensation settings to
achieve acceptable measurements to the IEC-60118-4
standard.
5.5 Operation of the fault contact
When the amplifier is working
properly, the NO/NC relay is
activated in the normally closed
position:NC.
5.4 Metal loss compensation adjustment
The OP-V plexiglass plate (option:not supplied)
allows you to lock the settings while viewing the
amplifier's information
LEDs.
This plexiglass can be
installed with or
without the OP-R
rack system.
Note:You can download asample certificate of
conformity from our website www.opus-
technologies.fr in the download section.Or use the
one provided at the end of this manual.
For more information on IEC-60118-4 standard
adjustments contact us at contact@opus-
technologies.fr or contact your local reseller.
13. Connect the two loops and then adjust the
settings until aminimum signal of -3dB is achieved
in the weakest audio reception area.
14. Then follow the test procedure described in the
OP-FSM manual to perform an installation
according to the IEC-60118-4 standard.
5.2.3 Final adjustments
5.3 Securing the settings
5.6. Audio input
5.6.1 Sensitivity
If the fault synthesis detects an operating problem
(broken loop, wrong loop impedance, amplifier
failure, etc.) the NO/NC relay is deactivated in the
normally open position:NO.
The level of INPUT 2and INPUT 3can be adjusted
according to the audio source used.
•When the audio source connected to one of the
inputs is amicrophone, set the grey button to the
Mic position.
•When the audio source connected to one of the
inputs is line level, position the grey button
released on the Line position.
5.6.2 Phantom power
The Phantom DIP switch on the rear panel of the
amplifier (see previous figure) enables or disables
phantom power for microphones that require
voltage to operate.
When using a phantom power:
•If the audio source of the INPUT 2and/or INPUT
3is amicrophone that needs voltage:
oThe DIP switch must be up
•When the audio source of the INPUT 2and/or
INPUT 3is amicrophone does not require
voltage:
oThe DIP switch must be down
•If the audio source is music:
oThe DIP switch must be down
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6. Functioning and planning of a loop system
6.1 Preamble
Astudy revealed that more than 60%of the
Magnetic Induction Loop installations do not work or
work poorly, far from the requirements of the
standard (IEC-60118-4). Indeed, the main difficulty
lies in the implementation of the loop path.This
observation led us to seek and provide effective
solutions to meet this standard.
It is therefore important to carefully read the
following instructions to ensure proper operation of
the system and compliance with the IEC-60018-4
standard.Do not hesitate to contact your local
distributor, we can help you with the study phase
before the installation of the system.
6.2Working principle
6.2.1 The magnetic field
When an alternating current flows through acopper
cable, it generates amagnetic field.
The intensity of the magnetic field is directly related
to the intensity of the electric current flowing in the
cable.
6.2.2 Magnetic field diffusion in a loop
When the intensity of the current flowing in aloop is
adapted to the width of the room to be equipped, the
radiation of this one makes it possible to cover the
whole room.
Illustration of an electromagnetic wave
around a conductor -Figure 10
Top view of a loop installation in a room -
Figure 11
Cable (conductor)
The floor
No reception on the
cable (shadow zone) Area with a constant
magnetic field
Sectional view of a loop installation in a
room -Figure 12
Magnetic field
radiation
Audio reception
LD Series |Installation and user manual
User manual