Void Arcline 8 User manual

Arcline 8/212
User Guide V1.0

©2019 Void Acoustics Research Ltd.
Version 1.0
This user guide is subject to change without notice.
For the latest online version, visit: www.voidacoustics.com
Void Acoustics and the Void logo are registered trademarks of Void
Acoustics Research Ltd. in the United Kingdom, USA and other
countries; all other Void trademarks are the property of Void Acoustics
Research Ltd.

Arcline 8/212 User Guide V1.0 Page 3
Contents
1 Safety and regulations 4
1.1 Important safety instructions 4
1.2 Limitations 4
1.3 EC declaration of conformity 4
1.4 WEEE directive 4
2 Limited warranty 5
3 Unpacking and Checking 6
4 About 7
4.1 Welcome 7
4.2 Arcline 8 7
4.2.1 Overview 7
4.2.2 Key features 7
4.2.3 Arcline 8 specifications 8
4.2.4 Arcline 8 dimensions 9
4.3 Arcline 212 10
4.3.1 Overview 10
4.3.2 Key features 10
4.3.3 Arcline 212 specifications 10
4.3.4 Arcline 212 dimensions 11
4.4 System compliance 12
5 Cabling and wiring 13
5.1 Electrical safety 13
5.2 Cable consideration for fixed
installations
13
5.3 Arcline 8 wiring diagram 14
5.4 Arcline 212 wiring diagram 14
5.5 Arcline 8 Bias Q5 speakONTM wiring 15
5.6 Arcline 212 Bias Q5 speakON™ wiring 16
6 Amplification and control 17
6.1 System control using Armonía 17
7 System design 18
7.1 Hearing safety 18
7.2 System design basics 18
7.3 EASE Focus 3 prediction software 20
7.4 Array design using EASE Focus 3 20
7.4.1 How many cabinets? 20
7.4.2 100 m flat field example 21
7.4.3 Manually adjusting splay and gain 25
7.2.4 Balconies and bleachers 27
8 Flying and stacking 29
8.1 Arcline rigging components and key
features
29
8.1.1 Arcline fly frame 29
8.1.2 Laser/inclinometer 30
8.1.3 Arcline 8 31
8.1.4 Arcline 212 34
8.2 Rigging safety 36
8.3 Typical flying procedure 36
8.4 Stacking 41
9 Typical configurations 44
9.1 Stacking 44
9.2 Flying Arcline 8 45
9.3 Flying Arcline 8 with Arcline 212 46
10 Service 47
11 Appendix A - Line array basics 48
12 Appendix B - Accessories 66
13 Appendix C - Connectors and cabling 67
14 Appendix D - Architectural specifications 69

Arcline 8/212 User Guide V1.0 Page 4
1.1 Important safety instructions
The lightning flash with an arrowhead symbol
within an equilateral triangle is intended to alert the
user to the presence of uninsulated “dangerous
voltage” within the product’s enclosure that may
be of sucient magnitude to constitute a risk of
electric shock to persons.
The exclamation point within an equilateral triangle
is intended to alert the user of the presence of
important operating and maintenance (servicing)
instructions in the literature accompanying the
appliance.
Safety instructions - read this first
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install in accordance
with the manufacturer’s instructions.
8. Do not install near any heat source such as radiators, heat
registers, stoves, or other such 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 power cords from being walked on or pinched
particularly at plugs, convenience receptacles, and the point
where they exit the apparatus.
11. Onlyuseattachmentsandaccessoriesspecifiedby Void
Acoustics.
12. Only use with the cart, stand, tripod, bracket, or table specified
by the manufacturer, or sold with the apparatus. When a
cart is used, use caution when moving the cart/apparatus
combination to avoid injury from tip-over.
13. Unplugtheapparatusduringlightningstormsorwhenunused
forlongperiodsoftime.
14. Refer all servicing to qualified service personnel. Servicing
is required when the apparatus has been damaged in
any way, such as when the power-supply cord or plug is
damaged, liquid has been spilled or objects have fallen into
the apparatus, the apparatus has been exposed to rain or
moisture, does not operate normally, or has been dropped.
15. Since the mains power supply cord attachment plug is used
to disconnect the device, the plug should always be easily
accessible.
16. Void loudspeakers can produce sound levels capable
of causing permanent hearing damage from prolonged
exposure. The higher the sound level, the less exposure
needed to cause such damage. Avoid prolonged exposure to
the high sound levels from the loudspeaker.
1.2 Limitations
This guide is provided to help familiarise the user with the
loudspeaker system and its accessories. It is not intended to provide
comprehensive electrical, fire, mechanical and noise training and is
not a substitute for industry-approved training. Nor does this guide
absolve the user of their obligation to comply with all relevant
safety legislation and codes of practice.
While every care has been taken in creating this guide, safety is
user-dependent and Void Acoustics Research Ltd cannot guarantee
complete safety whenever the system is rigged and operated.
1.3 EC declaration of conformity
Manufacturer:
Void Acoustics Research Ltd,
Unit 15 Dawkins Road Ind Est,
Poole, Dorset,
BH15 4JY,
United Kingdom.
We declare that under our sole responsibility the following product
models: Arcline 8, Arcline 212
are intended to be used as loudspeakers and are in conformity with
the following EC Directives, including all amendments, and with
national legislation implementing these directives:
• BS EN 60065:2002
• BS EN 55103-1/-2
March 2016
Alex Skan
Technical Director
1.4 WEEE directive
If the time arises to throw away your product, please recycle all the
components possible.
This symbol indicates that when the end-user
wishes to discard this product, it must be sent
to separate collection facilities for recovery
and recycling. By separating this product from
other household-type waste, the volume of
waste sent to incinerators or land-fills will be
reduced and natural resources will thus be
conserved.
The Waste Electrical and Electronic Equipment Directive (WEEE
Directive) aims to minimise the impact of electrical and electronic
goods on the environment. Void Acoustics Research Ltd complies
with the Directive 2002/96/EC and 2003/108/EC of the European
Parliament on waste electrical finance the cost of treatment and
recovery of electronic equipment (WEEE) in order to reduce the
amount of WEEE that is being disposed of in land-fill sites. All of
our products are marked with the WEEE symbol; this indicates that
this product must NOT be disposed of with other waste. Instead
it is the user’s responsibility to dispose of their waste electrical
and electronic equipment by handing it over to an approved
reprocessor, or by returning it to Void Acoustics Research Ltd for
reprocessing. For more information about where you can send
your waste equipment for recycling, please contact Void Acoustics
Research Ltd or one of your local distributors.
1 Safety and regulations

Arcline 8/212 User Guide V1.0 Page 5
The warranty
For a period of three (3) years from the date of
delivery to the original purchaser (as shown on the
original invoice or sales receipt; a copy of this may be
required as proof of warranty dates), Void Acoustics
Research Ltd (hereinafter ‘Void’) warrants to the
Original Owner (person or company who originally
purchased the product brand new from either Void
or a Void Authorised Dealer/Distributor) of each new
Arcline Series product (provided it was purchased at
an Authorised Void Dealer) that it is free of defects
in materials and workmanship and that each
product will meet or exceed all factory published
specifications for each respective model. Void agrees
to repair or replace (at its discretion) all defective
parts at no charge for labour or materials; subject to
following provisions:
Warranty violations
Void shall take no responsibility for repair or
replacement as specified under this warranty, if
the damaged product has been subject to misuse,
accident, neglect or failure to comply with normal
maintenance procedures; or if the serial number
has been defaced, altered or removed. Nor will Void
accept responsibility for, or resulting from, improper
alterations or unauthorised parts or repairs. This
warranty does not cover any damage to speakers
or any other consequential damage resulting from
breach of any written or implied warranty.
Void warranty provisions
Void will remedy any defect, regardless of the
reason for failure (except as excluded) by repair, or
replacement. Void will remedy the defect and ship
the product within a reasonable time after receipt of
the defective product at a Void Authorised Service Centre.
To obtain warranty service
If a Void product requires service, the Owner must
contact Void or an Authorised Void Service Centre to
receive an R.A.N. (Return Authorisation Number) and
instructions on how to return the product to the Void
Authorised Service Centre, or to Void.
Void (or its Authorised Service Centre) will initiate
corrective repairs upon receipt of the returned
product. Please save the original carton and all the
packing materials in case shipping is required. All
products being returned to the factory or service
centre for repairs must be shipped prepaid.
If the repairs made by Void or the Void Authorised
Service Centre are not satisfactory, the Owner
is instructed to give written notice to Void. If the
defect or malfunction remains after a reasonable
number of attempts by Void to remedy the defect
or malfunction, the Original Owner shall then have
the option to elect either a refund or replacement of
said Void product free of charge. The refund shall be
an amount equal to but not greater than the actual
purchase price, not including any taxes, interest,
insurance, closing costs and other finance charges
(minus reasonable depreciation on the product).
If a refund is necessary, the Original Owner must
make the defective or malfunctioning product
available to Void free and clear of all liens or other
restrictions.
Equipment modifications
Technical and design specifications are subject to
change without notice.
Void reserves the right to modify or change
equipment (in whole or part) at any time prior to
delivery thereof, in order to include therein electrical
or mechanical improvements deemed appropriate
by Void, but without incurring any liability to modify
or change any equipment previously delivered, or
to supply new equipment in accordance with any
earlier specifications.
Disclaimer of consequential and incidental
damages
You, the Original Owner, are not entitled to recover
from Void any incidental damages resulting from any
defect in the Void product.
This includes any damage to another product or
products resulting from such a defect.
Warranty alterations
No person has the authority to enlarge, amend, or
modify this Warranty. This Warranty is not extended
by the length of time which the Original Owner
is deprived of the use of product. Repairs and
replacement parts provided pursuant to the Warranty
shall carry only the non-expired portion of the
Warranty.
This Statement of Warranty supersedes all
others contained in this user guide.
2 Limited warranty

Arcline 8/212 User Guide V1.0 Page 6
All Void Acoustics products are carefully manufactured and thoroughly tested before being
dispatched. Your dealer will ensure that your Void products are in pristine condition before
being forwarded to you but mistakes and accidents can happen.
Before signing for your delivery:
• Inspect your shipment for any signs of contamination, abuse or transit damage as soon as
you receive it
• Check your Void Acoustics delivery fully against your order
• If your shipment is incomplete or any of its contents are found to be damaged; inform the
shipping company and inform your dealer.
Arcline loudspeakers are heavy and require a minimum two people to lift.
• Undo the four butterfly catches on the transport case then remove the lid making sure the
lid is clear before moving sideways
• If you need to place the Arcline on a flat surface ensure you use a lint free product to
protect the finish
• When removing the Arcline take care not to damage the lower tray of the transport case.
Keep the original packaging in case you need to return a product for service later.
See section 2 for warranty conditions and see section 9 if your product needs servicing.
3 Unpacking and checking

Arcline 8/212 User Guide V1.0 Page 7
4.1 Welcome
Many thanks for purchasing this Void Acoustics Arcline Series product. We truly appreciate
your support. At Void, we design, manufacture and distribute advanced professional audio
systems for the installed and live sound market sectors. Like all Void products, our highly
skilled and experienced engineers have successfully combined pioneering technologies with
groundbreaking design aesthetics, to bring you superior sound quality and visual innovation. In
buying this product, you are now part of the Void family and we hope using it brings you years
of satisfaction. This guide will help you both use this product safely and ensure it performs to
its full capability.
4.2 Arcline 8
4.2.1 Overview
A host of new technologies dramatically improve the perceived sound quality and definition
of the Arcline 8, while an advanced rigging system reduces setup time and the need for more
than one person to rig multiple enclosures. Delivering a true 110-degree dispersion results in a
highly uniform polar pattern, bringing uniform sound quality across the entire sound field.
The high frequency horn design optimises the waveguide and a new phase shading device
allows multiple Arcline 8 enclosures to form a true cylindrical wavefront by splitting two
acoustic sources into four, with the acoustic centre positioned optimally for coupling. Rigging
angles can also be pre-selected before flying the system.
4.2.2 Key features
• Two-way active, three-way line array module
• 110° horizontal dispersion
• True cylindrical wavefront
• 2 x 8” mid transducers with phase devices
• 2 x 8” horn loaded low frequency transducers
• 2 x 1.4’’ compression drivers
• Rigging angle pre-selected before lifting the enclosures
• Ground stackable
4 About

Arcline 8/212 User Guide V1.0 Page 8
4.2.3 Arcline 8 specifications
Frequency response 110 Hz - 20 kHz single enclosure, 90 Hz - 20 kHz three enclosures ±3 dB
Eciency1LF: 97 dB (100 dB referenced to 1 W) | MF/HF: 103 dB (106 dB
referenced to 1 W)
Crossover points LF: 110 Hz - 300 Hz, HMF: 300 Hz - passive 1.2 kHz
Nominal impedance 2 x 16 Ω
Power handling2LF: 500 W AES, HF: 500 W AES
Maximum output3128 dB cont, 145 dB peak
Driver configuration 2 x 1.4” compression drivers
2 x 8” mid drivers with phase device
2 x 8” horn loaded low frequency drivers
Dispersion 110°H x 12°V
Protection Internal electronic control
Connectors 2 x 4-pole speakON™ NL4
Height 285 mm (11.2”)
Width 881 mm (34.7”)
Depth 470 mm (18.5”)
Weight 39 kg (86 lbs)
Enclosure 15 mm multi-laminate plywood
Rigging Rigging angle pre selected before you lift the enclosures
Ground stackable
A2 stainless steel
Finish Textured TourCoat polyurea
Grille Perforated steel with foam filter
1Measured in half space 2AES2 - 1984 compliant 3Calculated
4 About

Arcline 8/212 User Guide V1.0 Page 9
4.2.4 Arcline 8 dimensions
733.5 (28.9”)
881 (34.7”)
285 (11.2”)
733.5 (28.9”)
881 (34.7”)
469.9
470 (18.5”)
285 (11.2”)
229.5
881 (34.7”)
733.5 (28.9”)
881 (34.7”)
470 (18.5”)
Figure 4.1: Arcline 8 dimensions
4 About

Arcline 8/212 User Guide V1.0 Page 10
4 About
4.3 Arcline 212
4.3.1 Overview
Specially designed to extend the low frequency range of the Arcline line array, the Arcline 212
features two 12” 900 W low frequency drivers. This makes it possible to extend the frequency
response range to as low as 50Hz, while also reaching up to 200Hz.
For ease, the Arcline 212 is flyable with the Arcline 8. It can be used in any application where
suspended bass is required, including large venues and medium to large scale touring.
Two Neutrik speakON™ NL4 connectors provide input and link through connections. Its
lightweight birch plywood enclosure is finished in a textured TourCoat polyurea finish, bringing
longevity for life on the road.
4.3.2 Key features
• Extended frequency range from 55 Hz to 120 Hz
• Flyable with Arcline 8
• Cardioid configuration integrated in the rigging
• FEA optimised porting
4.3.3 Arcline 212 specifications
Frequency response 50 Hz to 200 Hz
Eciency199 dB
Nominal impedance 2 x 8 Ω
Power handling22 x 900 W AES
Maximum output3132 dB cont, 138 dB peak
Driver configuration 2 x 12” low frequency drivers
Dispersion Array dependent
Connectors 2 x 4-pole speakON™ NL4
Height 367 mm (14.4”)
Width 877.5 mm (34.5”)
Depth 470 mm (18.5”)
Weight 42 kg (92.6 lbs)
Enclosure 15 mm multi-laminate plywood
Rigging A2 stainless steel rigging for use with Arcline 8 when flown or
ground stacked
Finish Textured TourCoat polyurea
Grille Perforated steel with foam filter
1Measured in half space 2AES2 - 1984 compliant 3Calculated

Arcline 8/212 User Guide V1.0 Page 11
4 About
4.3.4 Arcline 212 dimensions
876 (34.5”)
733.5 (28.9”)
365 (14.4”)
470 (18.5”)
Figure 4.2: Arcline 212 dimensions

Arcline 8/212 User Guide V1.0 Page 12
4.4 System compliance
Product Standards applied Limitations of use
Arcline 8 fly frame BGV C1 Conforms to BGV C1 for suspending:
15 Arcline 8 line-array elements
BS7906-1 Category A Conforms to BS7906-1 Category A for
suspending:
19 Arcline 8 line-array elements
BGV D8 and
BS7906-1 Category B
Conforms to BGV D8 and BS7906-1 Category
B for suspending:
24 Arcline 8 line-array elements as a static
load with secondary suspension
Arcline 8 line-array
element suspension
system
BGV C1 Conforms to BGV C1 for suspending:
15 Arcline 8 line-array elements
BS7906-1 Category A Conforms to BS7906-1 Category A for
suspending:
19 Arcline 8 line-array elements as a dynamic
load without secondary suspension
BGV D8 and
BS7906-1 Category B
Conforms to BGV D8 and BS7906-1 Category
B for suspending:
24 Arcline 8 line-array elements as a static
load with secondary suspension
Arcline 212 fly frame BGV C1 Conforms to BGV C1 for suspending:
14 Arcline 212 line-array elements
BS7906-1 Category A Conforms to BS7906-1 Category A for
suspending:
17 Arcline 212 line-array elements
BGV D8 and
BS7906-1 Category B
Conforms to BGV D8 and BS7906-1 Category
B for suspending:
24 Arcline 212 line-array elements as a static
load with secondary suspension
Arcline 212 line-
array element
suspension system
BGV C1 Conforms to BGV C1 for suspending:
14 Arcline 212 line-array elements
BS7906-1 Category A Conforms to BS7906-1 Category A for
suspending:
17 Arcline 212 line-array elements as a
dynamic load without secondary suspension
BGV D8 and
BS7906-1 Category B
Conforms to BGV D8 and BS7906-1 Category
B for suspending:
24 Arcline 212 line-array elements as a static
load with secondary suspension
Note: Must be safetied once in position.
4 About

Arcline 8/212 User Guide V1.0 Page 13
5 Cabling and wiring
5.1 Electrical safety
To avoid electrical hazards please note the following:
• Only connect electrical equipment to 50-60 Hz AC power outlets rated at 100-
120 VAC or 200-240 VAC
• Do not supply electrical power to equipment without a safety ground connection
• Do not supply electrical power to equipment that has been exposed to moisture (e.g. rain)
• Do not supply electrical power to equipment that has become coated in moisture (e.g.
condensation)
• Do not access the inside of any electrical equipment. Refer servicing to Void-approved
service agents.
5.2 Cable considerations for fixed installations
We recommend specifying installation-grade Low Smoke Zero Halogen (LSZH) cables for
permanent installations. The cables should use Oxygen Free Copper (OFC) of grade C11000
or above. Cables for permanent installations should be compliant with the following standards:
• IEC 60332.1 Fire retardancy of a single cable
• IEC 60332.3C Fire retardancy of bunched cables
• IEC 60754.1 Amount of Halogen Gas Emissions
• IEC 60754.2 Degree of acidity of released gases
• IEC 61034.2 Measurement of smoke density.
We suggest using the following maximum copper cable lengths to keep level losses below 0.6 dB.
Arcline cabinets in parallel 2 x Arcline 8 4 x Arcline 8
1 x Arcline 212 2 x Arcline 212
Metric mm2Imperial AWG 8 Ωload 4 ΩLoad
2.5 mm213 AWG 36 m 18 m
4 mm211 AWG 60 m 30 m

Arcline 8/212 User Guide V1.0 Page 14
5.3 Arcline 8 wiring diagram
5 Cabling and wiring
+
-
+
-
1+
1-
2+
2-
1+
1-
2+
2-
1+
1-
2+
2-
1+
1-
2+
2- Passive crossover
In
Out/Link
1.4” HF
8” MF
+
-
8” MF
+
-
1.4” HF
+
-
8” LF
+
-
8” LF
Figure 5.1: Arcline 8 wiring diagram
speakONTM pins 1+/1- speakONTM pins 2+/2-
In LF (2 x 8”) MHF (2 x 8” and 2 x 1.4”)
Out LF link MHF link
5.4 Arcline 212 wiring diagram
+
-
1+
1-
2+
2-
1+
1-
2+
2-
1+
1-
2+
2-
1+
1-
2+
2-
In
Out/Link
12” LF
+
-
12” LF
speakONTM pins 1+/1- speakONTM pins 2+/2-
In LF (12”) LF (12”)
Out LF link LF link
Figure 5.2: Arcline 212 wiring diagram

Arcline 8/212 User Guide V1.0 Page 15
5.5 Arcline 8 Bias Q5 speakONTM wiring
LF 1+
LF 1-
MHF 2+
MHF 2-
LF 1+
LF 1-
MHF 2+
MHF 2-
Figure 5.3: Arcline 8 Bias Q5 wiring
Bias Q5 Output 1 Output 2
Output LF (2 x 8”) MHF (2 x 8” and 2 x 1.4”)
Note that Q5 amplifier output channels do not share a common ground for “1-”
and “2-”
• Avoid grounding Q5 amplifier outlet pins or loudspeaker connector pins
• Never wire loudspeaker installation panels with common Ch1 and Ch2 loudspeaker
return lines
5 Cabling and wiring

Arcline 8/212 User Guide V1.0 Page 16
5 Cabling and wiring
5.6 Arcline 212 Bias Q5 speakONTM wiring
Figure 5.4: Arcline 212 Bias Q5 wiring
Bias Q5 Output 1 Output 2
Output LF (12”) LF (12”)
Note that Q5 amplifier output channels do not share a common ground for “1-”
and “2-”
• Avoid grounding Q5 amplifier outlet pins or loudspeaker connector pins
• Never wire loudspeaker installation panels with common Ch1 and Ch2 loudspeaker return
lines
LF 1+
LF 1-
LF 2+
LF 2-
LF 1+
LF 1-
LF 2+
LF 2-

Arcline 8/212 User Guide V1.0 Page 17
6.1 System control using Armonía software
Arcline systems are powered by Bias Q5 DSP power amplifiers that are controlled via
Powersoft’s Armonía Plus System Manager.
Armonía Plus System Manager software, updates and tutorials are provided via the www.
powersoft-audio.com website as follows:
Armonía on-line support go to https://armonia.powersoft.it/ for details
Ensure that all your Bias Q5 amplifiers are loaded with the same firmware version.
1. Dierent firmware versions on dierent amplifiers may lead to latency mismatches
2. Keeping your amplifier firmware up-to-date will ensure that your Bias Q5 amplifiers work
with the latest version of Armonía Plus.
Arcline presets and updates
All void prestes are available through the marketplace in Armonia Plus as well as the latest
firmware updates.
Figure 6.6: Armonía Plus workspace for a Void Arcline 8/Arcline 212/Arcline 218
6 Amplification and control

Arcline 8/212 User Guide V1.0 Page 18
7.2 System design basics
Void Acoustics Arcline systems may be vertically arrayed to form high-power line array
systems of exceptional quality.
The following points should be considered when designing any vertically-arrayed sound
system:
• Point-source (non-line array) loudspeaker sound pressure level (SPL) reduces at
approximately 6 dB per doubling of distance unless something is done to compensate
for this natural radial attenuation. A line array behaves more like a point-source at lower
frequencies where its line length is short when compared with low frequency wavelengths
• Modern PA line arrays rely on multiple cabinet summation to partially compensate for
this single-cabinet radial attenuation. A vertical array of cabinets is formed that is relatively
straight at the top (for maximum vector summation), with increasing curvature towards the
bottom (to tailor the summation to the coverage requirements). See Appendix A for line
array basics
• The line array eect is limited by:
• The number of cabinets available to provide far audience level compensation
• The length of the array. Low frequency projection is related to the square of the line
length (acoustically-small arrays, with respect to wavelength, revert to point-source
radial attenuation)
• The array curvature. Summation is related to coverage overlap between multiple
cabinets and becomes more critical at high frequencies where the vertical directivity
of individual cabinets is higher and where multiple arrival phase shifts reduce vector
summation.
7 System design
To avoid noise hazards, please note the following:
• Public address loudspeakers are designed to project sound to a large audience and are
not designed for close listening. Do not place your ear too close when checking individual
loudspeakers in case someone inadvertently unmutes an audio channel or increases its
level without warning
• Design your system to provide smooth coverage. This will ensure that you project sound to the
rear of the audience without overexposing audience members and venue sta at the front
• Venue managers should swap sta around occasionally, to reduce the cumulative eect of
noise exposure on individual sta members
• Ensure you comply with the relevant noise exposure/noise at work regulations. There is a
very useful web site covering the topic. See www.soundadvice.info
• Unweighted and/or short-term sound pressure levels will usually be higher as A-weighting
under-represents the LF and HF content and LEQ measurements are averaged over a
specified time interval
• Instantaneous/peak sound pressure levels must never exceed 137dB unweighted*
(*Overexposure to low frequencies used to be disregarded but it is now understood to cause
significant hearing damage)
7.1 Hearing safety

Arcline 8/212 User Guide V1.0 Page 19
7 System design
Long-distance sound propagation can be adversely aected by:
• Temperature gradients: The speed of sound increases with temperature so any
temperature dierence with height can cause the sound propagation to rotate upwards
when the air near the surface is warmer than the air higher up (e.g. a warm, sunny day),
or to rotate downwards when the air near the surface is cooler than the air higher up (e.g.
after summer showers or during ice shows)
• Wind gradients: As sound normally relies on air as a medium, the speed of sound is relative
to the air and not to the ground. So the resultant speed of sound may be increased by air
movement in the direction of the sound propagation or decreased by air movement in the
opposite direction. Wind speed varies with height so its eect on sound also varies with
height. A wind blowing from the stage will cause sound propagation to rotate downwards,
whereas wind blowing towards the stage will cause sound propagation to rotate upwards.
A cross-wind will cause the sound direction to be “blown” sideways often resulting in
“phasing” due to multiple arrival time changes with changing wind speeds
• Air absorption: When air resonates under the influence of the sound propagating
through it, the air absorbs energy from that sound – particularly at mid and high
frequencies. The “tuning” of that resonance varies with temperature and relative
humidity in a complex way but tends to be worse around 20% RH and worse at higher
frequencies. The significant thing about air absorption is that it attenuates (in dB) over
linear distance – not per-doubling as with radial attenuation. Air absorption can be as
high as 0.287 dB per metre (10 kHz) at 22°C, 20% RH = 28.7 dB over 100 m.
See Appendix A for more in-depth information and guidance.
As temperature gradients can vary significantly over a period of a few minutes – especially
inside a big open-roof stadium after sunset, and wind gradients can vary from second to
second, it’s dicult to correct for them completely. It’s usually more practical to design
systems for the worse-case scenario – i.e. slightly over-designing systems for longer coverage
and then retaining some network control over level shading to compensate for any long-term
eects.
Air absorption tends to vary over far longer periods of time so it can be partially compensated
for by designing line array HF sections for maximum eciency and headroom and then
by adding mid-hi/HF shelving EQ into the loudspeaker management presets for the upper
sections of large “long-throw” arrays.
Delay towers should always be considered and budgeted for when designing
system to cover more than 100 m in low humidity conditions. Relative humidity
often falls below 30% on dry summer days – even in Northern Europe.

Arcline 8/212 User Guide V1.0 Page 20
7 System design
Prediction software
Poorly designed sound systems will quickly fail to deliver in adverse weather conditions so
design your sound system for the best performance possible to avoid climatic conditions
hindering with system performance.
To simplify day-to-day system design, the Void Acoustics Arcline 8 system has been designed
to be compatible with industry-standard EASE Focus 3 prediction software.
7.3 EASE Focus 3 prediction software
EASE Focus software and updates are provided via the http://focus.afmg.eu web site.
On-line EASE Focus 3 information
• Go to http://focus.afmg.eu for details
• An on-line introduction will be found at: www.afmg-support.eu/AFMGDownloads/
Downloads.aspx?SWP=EASE%20Focus&FILE=EASE_Focus_3_Mail.pdf
• Frequently asked questions are covered here: http://focus.afmg.eu/index.php/fc-faq-en.html
• The latest version is EASE Focus 3.0.18 – available to download free of charge
from: www.afmg-support.eu/AFMGDownloads/Downloads.aspx?SWP=EASE%20
Focus&FILE=EASE_Focus_v3.0.18.zip
• Windows 7 requires Microsoft .NET Framework 4.0 - available from: https://www.microsoft.
com/en-us/download/details.aspx?id=17851
7.4 Array design using EASE Focus 3
7.4.1 How many cabinets?
The following factors should be considered:
• Maximum low frequency SPL will increase by approximately 6 dB for every doubling of
cabinet quantities
• Low-mid to high-mid far audience spectral balance will vary with eective* array length for
a given distance so it’s important to maintain low curvature (low single-figure splay angles)
over most of the array by not flying too high and by using front fills – if possible – to cover
the front rows. Front fills also improve imaging
• Air absorption may curtail HF propagation over long distances in dry conditions so, again,
it’s important to maintain headroom by using low-curvature array designs.
* This would only include cabinets whose coverage contributes to the SPL at the listener
distance. For instance, the far audience wouldn’t benefit from the mid & HF output from the
bottom cabinets as the listeners would be out of their coverage.