Ampetronic HLS-2D Reference guide
HLS-2D
Metal Loss Test
Procedure
www.ampetronic.com
Test kit contents
• HLS-2D loop driver
• 12V DC power supply
• 2 x 4mm connector plugs for the loop cable
(cable not supplied)
• 3.5mm audio cable
1. Separate indication for power, input signal and
loop current
2. Loop output connectors using standard 4mm
banana plug test sockets
3. 12V DC power input, 2.1mm centre positive
4. Audio input, 3.5mm stereo jack
Additional equipment required
• R1 Receiver with iOS Device and Loopworks app or FSM with test record sheet
• Signal source - mobile phone, MP3 player or signal generator, with Ampetronic test tones
• Loop cable - 25 to 30m (80-100ft) of 1.5mm2 (AWG 16) single core wire tted with supplied
connectors
• Tape measure
Test signals and record sheet template available from www.ampetronic.com/signals
Optional equipment
• True RMS multimeter to monitor output current
• Additional short link cable (2x4mm connectors) if multimeter is used
• 12 volt battery (a fully charged 12 volt 4800mAH battery will give approximately 8 hours of
testing time)
Document outline
Determining metal loss and background noise levels are important steps in designing a proper
hearing loop system that meets the IEC 60118-4 international standard.
This test procedure uses the HLS-2D loop driver which is mounted in a compact rugged case and
pre-set to simplify and reduce set-up and testing time.
The document will guide you through the metal loss and background noise testing process utilising
either the R1 Loopworks Measure Receiver, or the FSM (eld strength meter).
BB77920-3
HLS-2D Metal Loss Test Procedure
Page 1
HLS-2D Metal Loss Test Procedure Page 2
Choosing an area coverage loop system
There are two types of loop systems for covering a room or area although assuming that a perimeter
loop is suitable is a good starting point as it will give you the least complex option and make
installation easier and cheaper.
Perimeter loops are suitable:
• when no spill control is required and
• there is less than 6dB variation between high and low signal readings across the eld.
MultiLoop™ systems are preferred for:
• Loss control: - Where there is >6dB variation, a gure of eight test loop is recommended,
with loop wires 2-4m (6.5 – 13ft) apart. Buildings with high concentrations of metal will typically
require the use of narrower loops, although loops wider than 4m may be possible, subject to
testing.
• Spill control: - Where control of overspill is required for condentiality or the presence of
adjacent spaces, a gure of eight test loop is recommended, but loop width should be limited to
2.0-2.5m (6.5-8ft).
• Large areas: - The signal in a oor-level perimeter loop wider (in the narrower dimension) than
15m (50ft) will vary greater than 6dB even with no metal content. Elevating the loop or using a
MultiLoop™ system will correct this. There is no restriction on the width of the test loop below
15m (50ft) and the designed loop width is likely to be dictated by installation practicalities e.g.
aisle placement.
Technical Specifications According to IEC 62489-1:2010 Standard
PARAMETER VALUE
Max area coverage 45m2
Power supply range 12-24V DC
Fuse PTC resettable 1.5A
Current consumption (12V DC)
Continuous pink noise 240mA DC
Quiescent 50mA DC
Quiescent (Power Save mode) 14mA DC
Short term peak 1200mA DC
Sensitivity Input 1 - Line -16dBu
Sensitivity Input 2 - Line -16dBu
Overload (Line channels) +22dBu
Current (into rated load) Sine 1kHz >3ARMS
Pink Noise >1.5ARMS
Frequency response (0.6ARMS) 100Hz to 5kHz ± 1.5dB
Compliance voltage 4.2VRMS
Weight 272g
Dimensions 77 x 150 x 16mm
Connectors 4mm banana plug sockets
Environmental IP40, -30°c to +75°c, <90% relative humidity
Typical heat dissipation <3W
WARRANTY
This product carries a ve year parts and labour warranty from date of shipment from Ampetronic. To
qualify for the ve year warranty, the product must be registered at www.ampetronic.com (products/
warranty), without which the warranty will be valid for two years only.
The warranty could be invalidated if the instructions in this handbook are not followed correctly, or if
the unit is misused in any way. Note: The PSU and connectors supplied with this product are only
covered by manufacturers warranty period.
Set-up procedure
Determine test loop location
Step 1. The test loop should be placed within the intended area to be looped and positioned at the
same height at which the nal loop will be installed.
Step 2. Take note of the construction of the area to be looped and ensure the test loops cover all
the various structural elements. The test loops should cross over any steel beams or large
ducts that may be present. If the area to be looped is very large, for example a large
theatre, repeat the test in multiple areas throughout the space to account for variances in
building structure.
Step 3. Complete a separate site assessment procedure, or a metal loss test form for each test
area and note the location of each test.
Perimeter Loop layout test loop
If a perimeter loop is going to be installed, then test with the actual intended loop layout.
Driver set-up
A. Connect the power supply (or battery), signal source (phone or MP3 player) and loop wire.
B. If using a multimeter this should be connected in series, using the high current connections
and set to the AC current option.
C. Switch on the power to the driver and check that the power LED illuminates, the Input LED
will also light up for a few seconds as the circuit settles.
Signal level test set-up and test positions
Set the signal input to sinewave or combination and turn up the volume of the signal input until the
input LED lights light up on the driver.
NOTE: continuous prolonged use of a sinewave signal (longer than 10 minutes) will cause the
output current to drop slightly, however this should not aect the output level by more than 1dB.
The combination signal avoids this.The current LED should also be on at this stage.
For perimeter loop tests, readings should be
taken in the middle, edge and near to at least
one of the corners of the loop, to measure the
maximum variation in signal strength across the
loop.
All testing positions should be at least 1m (3ft)
from the wires, as the signal level decreases near
to the wire, making readings unreliable.
Measurement height for the test meters should be at 1.2m (4ft) from the oor (typical seated head
height), whether the test loop is on the oor or ceiling.
All measurements must be carried out with the Loopworks Measure R1 or FSM positioned
vertically.
HLS-2D Metal Loss Test ProcedurePage 3
Additional considerations:- The presence of xed metal furniture and/or tiered seating may dene
the positions where a loop can be practically installed. If a perimeter loop cannot be used, the size
of the gure of eight loops should be determined by the xed features, e.g. loop widths should
cover 2-3 steps with a 1 step gap.
MulitiLoop™layout test loop
If the intended installation will be a low spill or loss control MultiLoop™ this should be a gure
eight as shown below.
It is better to use the least amount of wire to make the test loop. Any extra wire should kept away
from the loop and folded back on itself rather than coiled to avoid interference to the test.
For a oor level wire, the suggested dimensions will achieve 0dB in the centre of each loop if there
is no loss and will match most LoopworksTM designs, however larger loop segments can be used if
the intended design and installation is likely to require this.
Take some photographs of the loop layout for reference.
Driver set-up
A. Connect the power supply (or battery), signal source (phone or MP3 player) and loop wire.
B. If using a multimeter this should be connected in series, using the high current connections
and set to the AC current option.
C. Switch on the power to the driver and check that the power LED illuminates, the Input LED
will also light up for a few seconds as the circuit settles.
Signal level test set-up and test positions
Set the signal input to sinewave or combination and turn up the volume of the signal input until the
input LED lights light up on the driver.
NOTE: continuous prolonged use of a sinewave signal (longer than 10 minutes) will cause the
output current to drop slightly, however this should not aect the output level by more than 1dB.
The combination signal avoids this. The current LED should also be on at this stage.
For MultiLoop™ systems measurements should
be taken in the centre of the loop. In larger rooms
use more measurement positions to make sure
loss levels are consistent across the area.
All testing positions should be at least 1m (3ft)
from the wires, as the signal level decreases near
to the wire, making readings unreliable. If space is
restricted, a single loop can be used; however, this
is a less accurate representation of performance.
Measurement height for the test meters should be at 1.2m (4ft) from the oor (typical seated head
height), whether the test loop is on the oor or ceiling.
All measurements must be carried out with the Loopworks Measure R1 or FSM positioned
vertically.
HLS-2D Metal Loss Test Procedure Page 4
HLS-2D Metal Loss Test ProcedurePage 5
Tests with the R1 receiver and Loopworks Measure app
Open the app and connect the R1 to your device, select or create a project and system.
Press Stop Test to nish the measurement.
You can now log on to your Loopworks account online and open the measurement session,
download a PDF report of the data and either follow the interpreting results section or send it to
Ampetronic or your local distributor for analysis.
Dene test points Start Test, Start Site
Assessment Test then
name session
Fill in test loop details,
loop current is preset to
2.5A
Select Field Strength,
wait for sinewave peak
if using combination
tone
Save a result at each
test point, make sure to
reset the peak hold
Change the input signal
to pink noise, save a
frequency response
reading at each test
point
Turn the HLS-2D driver
o, save a background
noise reading at each
test point
HLS-2D Metal Loss Test Procedure Page 6
Test with FSM meter
Step 1. Record the details and dimensions of the test loop on the form.
Step 2. Select the Field Strength setting (middle mode of the lower switch), move to the rst test
position and measure the signal level on the white scale.
Step 3. Record the signal level on the test sheet and repeat this for all the test points.
Step 4. Change the input signal to pink noise.
Step 5. Switch the meter mode to Frequency Response.
Step 6. Select the 100Hz band and record the signal level as shown on the white scale, switch to
1kHz and repeat, then to the 5kHz.
Step 7. Repeat these measurements at all the test points and record all the results on the attached
record form.
Step 8. Turn the HLS-2D driver o, switch the meter mode to Background Noise and record the
reading from the green scale at each test point.
Step 9. Follow the interpreting results section or send a copy of your completed form to Ampetronic
or your local distributor for analysis.
HLS-2D Metal Loss Test ProcedurePage 7
Interpreting Results
Perimeter loop test for metal loss
If the dierence between your highest and lowest test reading is more than 6dB a perimeter loop
installation would not be able to meet the requirements of the IEC 60118-4 performance standard.
If possible, carry out a gure eight test to check if a loss control MultiLoop™ array would be more
suitable.
To calculate the metal loss create a perimeter loop of the same specication in Loopworks Design
and on the Outputs > Variation tab change the ‘Manual adjustment’ eld until the Base current
reads 2.5A. Determine the largest dierence between your test results and the simulated eld
strength, this is your ‘loss gure’.
Return the ‘Manual adjustment’ eld to 0dB and then enter your ‘loss gure’ into the ‘Use manual
loss gure’ eld on Inputs > Design.
Figure of eight test for metal loss
For a gure of eight test with loop segments of between 2m (6.5ft) and 4m (13ft) width, the
expected eld strength will be approximately 0dB, so the test result will be your metal loss value.
If an initial gure of eight test shows very little loss (< 4dB), try testing again with larger loop
segments as this may allow a more ecient installation, especially in larger spaces.
In Loopworks Design, assuming the loop segment widths on the design match your test loop size,
your test result can be entered into the ‘Use manual loss gure’ eld on Inputs > Design to specify
the most suitable amplier.
Interpreting frequency response
Correcting the frequency response is not normally an issue in multiloop systems, as long as there is
sucient voltage headroom allowed in the amplier.
Often it is possible to get much better results with Ampetronic dual slope MLC, as found on all our
network enabled drivers.
These drivers will allow up to 4dB/oct correction, so would compensate for a test 5kHz reading
down to -9dB (re. 1kHz) and a 100Hz reading of up to +13dB (re. 1kHz).
N.B. large MLC slopes require more headroom, a 4dB/oct correction could require up to an
additional 4dB of voltage headroom in the loop driver.
Perimeter loops can be more dicult, as the frequency response can vary more across the area,
eg. the eects of metal loss are usually more signicant in the middle of the loop, causing more
frequency loss.
If there is a lot of variation between slopes across dierent test positions (in general more than 3dB
dierence between the high or low readings, across multiple test points) then there may not be
a suitable MLC slope that could correct for all of these and a system with smaller loop segments
could be required.
If in doubt, contact Ampetronic or your local distributor for more in depth analysis of your frequency
results.
Tel: +44 (0) 1636 610062
Email: [email protected]
www.ampetronic.com
Ampetronic Ltd
Tel: +44 (0) 1636 610062
Email: [email protected]
www.ampetronic.com
EC Declaration of Conformity
Manufacturer: Ampetronic Ltd
Address: Unit 2, Trentside Business Village
Farndon Road
Newark
NG24 4XB
declare that:
Equipment Induction Loop Driver
Model name / number HLS-2D
in accordance with the following directives:
2014 / 35 / EU The Low Voltage Directive (LVD)
and its amending directives
2014 / 30 / EU The Electromagnetic Compatibility Directive (EMC)
and its amending directives
2014 / 53 / EU The Radio Equipment Directive (RED)
and its amending directives
2011 / 65 / EU The RoHS Directive
and its amending directives
has been designed and manufactured to the following specications:
LVD Safety Standard:
EN 60065:2014 Audio, video and similar electronic apparatus – Safety requirements
+A11:2017
RED Standard:
ETSI EN 303-348 Induction loop systems intended to assist the hearing impaired in the frequency range
V1.1.1 10Hz to 9kHz
EMC Standards:
EN 55032:2015 EMC – Product family standard multimedia equipment: Emission
EN 55103-2:2009 EMC – Product family standard for audio, video, audio-visual and entertainment
lighting control apparatus for professional use – Part 2: Immunity
with respect to electromagnetic environments: E1 – E5
I hereby declare that the equipment named above has been designed to comply to with
the relevant sections of the above specications. The unit complies with all essential
requirements of the Directives.
Date: May 2019
Name: J.R. Pieters
Position: Managing Director
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