L-Acoustics LA4X User manual

LA4X Amplified Controller
user manual
VERSION 4.0
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LA4X Amplified Controller
user manual
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IMPORTANT SAFETY INSTRUCTIONS
Explanation of Graphical Symbols
The lightning flash with 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
sufficient magnitude to constitute a risk of electric
shock to persons.
The exclamation point within an equilateral triangle
is intended to alert the user to the presence of
important operating and maintenance instructions in
the literature accompanying the product.
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 dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus
(including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the grounding-type plug. A grounding-type plug has two blades
and a third grounding prong. The third prong is provided for your safety. If the provided plug does not
fit into your outlet, consult an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at plugs, convenience
receptacles, and the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only 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 this 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 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. WARNING: To reduce the risk of fire or electric shock, this apparatus should not be exposed to rain
or moisture and objects filled with liquids, such as vases, should not be placed on this apparatus.
16. To completely disconnect this equipment from the mains, disconnect the power supply cord plug from
the receptacle.
17. The main plug of the power supply cord shall remain readily operable.

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ADDITIONAL IMPORTANT SAFETY INSTRUCTIONS
1. Read this manual.
2. Read all SAFETY INSTRUCTIONS carefully as well as DANGER and OBLIGATION warnings.
3. Never incorporate equipment or accessories not approved by L-ACOUSTICS®.
4. Read all the related PRODUCT INFORMATION documents before exploiting a loudspeaker system.
The product information document is included in the shipping carton of the related system component.
5. Strictly follow the installation instructions given in this manual.
To ensure sufficient ventilation, install the apparatus in an open area so that the front and rear panels are located
at a minimum distance of 30 cm from any external object or structure.
6. Read the MAINTENANCE MANUAL –LEVEL 1 before performing any maintenance operation on the
apparatus or in case of malfunction.
This manual only contains the maintenance operations authorized for the End User. Contact L-ACOUSTICS®for
advanced maintenance.
7. Inspect the apparatus before use.
If any sign of defect or damage is detected, immediately withdraw the apparatus from use for maintenance.
8. Only use the apparatus in a conformed electro-magnetic environment.
Conformed environments are specified in EN55103-2 standard as E1 (residential), E2 (commercial and light
industrial), E3 (urban outdoors), and E4 (controlled EMC environment, ex. TV studio).
9. Avoid radio interference.
This apparatus has been tested and complies with the limits indicated in the EMC (Electro Magnetic Compatibility)
directive. These limits are designed to provide reasonable protection against harmful interference from electrical
equipment, but it cannot be guaranteed that interference will never occur.
10. Verify the electrical conformity and compatibility of the mains supply.
Only connect the apparatus to an AC power outlet rated 100-240 V, 50-60 Hz, with the following current values:
20 A for 100-120 V, 10 A for 200-240 V.
WARNING: An apparatus with CLASS I construction shall be connected to a mains socket outlet with a protective
connection to earth.
11. Verify the electrical conformity and compatibility of the three-phase circuit.
Verify that each phase works, in particular the neutral one.
Balance the loads between the three phases.
Never try to reproduce a 230 V circuit connecting an apparatus to two live wires of a 120 V three-phase circuit.
Never try to reproduce a 200 V circuit connecting an apparatus to two live wires of a 100 V three-phase circuit.
12. Always interconnect a Class C thermal circuit breaker between the apparatus and the mains supply.
The circuit breaker current rating depends on the mains voltage rating as follows:
20 A for 100-120 V, 10 A for 200-240 V.
13. Be aware of over power risks.
The apparatus is very powerful and can be potentially dangerous to both loudspeakers and humans alike.
Even reducing the gain it is still possible to reach very high output power if the input signal level is high enough.
14. Do not use the apparatus outside its operating temperature range.
The apparatus operates at a room temperature between 0 °C and +50 °C.
Do not expose the apparatus to direct sun.
15. WARNING: TERMINALS marked with the lightning flash symbol are HAZARDOUS LIVE.
The external wiring connected to these TERMINALS requires installation by an INSTRUCTED PERSON
or the use of ready-made leads or cords.
Never attempt to touch any exposed speaker wiring while the apparatus is operating: first disconnect the
connector from the apparatus.
Mute all output channels before connecting a speaker to the apparatus.
Do not connect a speaker output in parallel or series with any output of another amplifier.
Do not connect the speaker outputs to any other voltage source, such as a battery, power mains, or
power supply, regardless of whether the apparatus is turned on or off.

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16. Do not place naked flame sources, such as lighted candles, on the apparatus.
17. Use the original packaging or accessories approved by L-ACOUSTICS®(rack, case) to transport the
apparatus.
SYMBOLS
The following symbols are used in this document:
DANGER
This symbol indicates a potential risk of harm to an individual or damage to the product.
It can also notify the user about instructions that must be strictly followed to ensure safe installation or operation
of the product.
ELECTRICAL HAZARD
This symbol indicates a potential risk of electrical injury.
It can also notify the user about instructions that must be strictly followed to ensure safe installation or operation
of the product.
OBLIGATION
This symbol notifies the user about instructions that must be strictly followed to ensure proper installation or
operation of the product.
EQUIPMENT
This symbol indicates the equipment, tools, and spare parts required to perform a procedure.
INFORMATION
This symbol notifies the user about complementary information or optional instructions.
WELCOME TO L-ACOUSTICS®
Thank you for choosing the L-ACOUSTICS®LA4X amplified controller.
This document contains essential information on using the product properly. Carefully read this document in order to
become familiar with the product.
As part of a continuous evolution of techniques and standards, L-ACOUSTICS®reserves the right to
change the specifications of its products and the content of its document without prior notice.
Please check the L-ACOUSTICS®web site on a regular basis to download the latest document and software updates:
www.l-acoustics.com.

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CONTENTS
1INTEGRATED SYSTEM APPROACH 7
1.1 Presentation ................................................................................................................................................................ 7
1.2 System configurations................................................................................................................................................... 7
1.3 System components ..................................................................................................................................................... 7
1.3.1 Powering and driving systems........................................................................................................................ 7
1.3.2 Loudspeaker enclosures and cables................................................................................................................ 7
1.3.3 Rigging elements........................................................................................................................................... 7
1.3.4 Software...................................................................................................................................................... 8
2LA4X AMPLIFIED CONTROLLER 9
2.1 Main features............................................................................................................................................................... 9
2.1.1 Internal components..................................................................................................................................... 9
2.1.2 Front and rear panels.................................................................................................................................... 9
2.2 Signal processing and amplification............................................................................................................................... 10
2.2.1 Signal inputs ............................................................................................................................................... 10
2.2.2 DSP architecture ........................................................................................................................................ 11
2.2.3 Power supply and amplifier section .............................................................................................................. 12
2.2.4 Speaker outputs ......................................................................................................................................... 12
2.3 Monitoring and control............................................................................................................................................... 12
2.3.1 User interface ............................................................................................................................................ 12
2.3.2 L-NET remote control network................................................................................................................... 12
3INSTALLATION 13
3.1 Mounting................................................................................................................................................................... 13
3.2 Ventilation................................................................................................................................................................. 14
3.3 Connecting to AC mains............................................................................................................................................. 14
3.3.1 AC mains specifications............................................................................................................................... 14
3.3.2 Three-phase circuit..................................................................................................................................... 14
3.3.3 Circuit breaker........................................................................................................................................... 14
3.3.4 Electrical generator..................................................................................................................................... 14
3.3.5 Power cord................................................................................................................................................ 15
3.3.6 Power consumption.................................................................................................................................... 15
3.3.7 Example of heat power calculation............................................................................................................... 15
3.4 Audio and network cabling.......................................................................................................................................... 16
3.4.1 Connection panels...................................................................................................................................... 16
3.4.2 Analog SIGNAL cabling ............................................................................................................................... 17
3.4.3 Digital SIGNAL cabling................................................................................................................................ 18
3.4.4 SPEAKER cabling ........................................................................................................................................ 19
3.4.5 L-NET cabling ............................................................................................................................................ 20
4OPERATION 21
4.1 Powering on, powering off, selecting the standby mode ................................................................................................ 21

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4.2 Display ...................................................................................................................................................................... 22
4.2.1 Main screen ............................................................................................................................................... 22
4.2.2 LED meters ............................................................................................................................................... 23
4.2.3 STATUS and L-NET LED ............................................................................................................................ 23
4.2.4 OUT LED.................................................................................................................................................. 23
4.3 User interface............................................................................................................................................................ 24
4.3.1 Quick access .............................................................................................................................................. 24
4.3.2 Main menu................................................................................................................................................. 27
4.3.3 Access rights, pin code................................................................................................................................ 28
4.4 LOAD PRESET .......................................................................................................................................................... 29
4.5 STORE PRESET ......................................................................................................................................................... 30
4.6 DELETE PRESET ....................................................................................................................................................... 31
4.7 PRESET PARAMETERS............................................................................................................................................... 32
4.8 CLEAR GROUP PARAMS ........................................................................................................................................... 33
4.9 INPUT SETTINGS ..................................................................................................................................................... 34
4.9.1 INPUT MODE ........................................................................................................................................... 34
4.9.2 FALLBACK MODE ..................................................................................................................................... 35
4.9.3 AES/EBU GAIN .......................................................................................................................................... 36
4.10 MONITORING AND INFO........................................................................................................................................ 37
4.10.1 SPK HANDLING........................................................................................................................................ 38
4.10.2 OUT CH TEMP ......................................................................................................................................... 38
4.10.3 FIRMWARE................................................................................................................................................ 38
4.10.4 PRESET LIBRARY ....................................................................................................................................... 38
4.10.5 MAC ADDRESS.......................................................................................................................................... 38
4.11 OPTIONS ................................................................................................................................................................. 39
4.11.1 NETWORK ADDRESS................................................................................................................................ 40
4.11.2 DELAY UNIT............................................................................................................................................. 40
4.11.3 SCREEN CONTRAST................................................................................................................................. 41
4.11.4 LED & BACKLIGHT MODE........................................................................................................................ 41
4.11.5 RESET TO FACTORY DEFAULT SETTINGS? .............................................................................................. 41
APPENDIX A: PROTECTION SYSTEMS 42
APPENDIX B: APPROVALS 43
APPENDIX C: SPECIFICATIONS 44

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1INTEGRATED SYSTEM APPROACH
1.1 Presentation
The LA4X is an amplified controller based on a 4-input by 4-output architecture and an exclusive green power module
providing maximized efficiency. With LA4X, L-ACOUSTICS®speakers can get all the benefits of self-powered
speakers, while keeping the versatility of the separated amplification approach.
1.2 System configurations
The L-ACOUSTICS®systems can be operated in three connectivity modes, as described below:
‘‘A LA CARTE’’
The pool of four inputs and four amplification channels of the LA4X can be allocated “à la
carte” to any passive speaker enclosures with a one-to-one-to-one link
(input / processing + amplification / loudspeaker). This approach is cost effective for
applications requiring a high count of independent sound sources such as stage monitors,
multi-channel systems and multi-feed distributed systems.
‘‘FULL ACTIVE’’
In high-end installation projects, the LA4X can drive active systems, up to K2, for maximum
power headroom and the best possible performances. With one transducer section per
output channel and the independent DSP treatment of each output, this approach brings
maximum discretization with a one-to-one link (processing + amplification / transducer
section).
‘‘CONVENTIONAL’’
For applications requiring a high count of loudspeaker enclosures with optimized cost of
amplification, the LA4X can efficiently operate as a conventional amplified controller driving
speakers in parallel from its four amplification channels, with the added benefit of the 4
inputs when using passive loudspeaker enclosures.
1.3 System components
The system approach developed by L-ACOUSTICS®consists in offering a global solution that guarantees the highest
and most predictable level of performance at any step of loudspeaker system deployment: modeling, installation and
operation. A complete L-ACOUSTICS®system includes enclosures, amplified controllers, cables, rigging system, and
software applications. The main components of an L-ACOUSTICS®system that includes the LA4X are the following:
1.3.1 Powering and driving systems
LA4X
Amplified controller with DSP library and networking capabilities.
1.3.2 Loudspeaker enclosures and cables
Refer to the user manuals of the loudspeaker systems for detailed instructions about the enclosures and their
connection to the LA amplified controllers.
1.3.3 Rigging elements
Refer to the rigging manuals of the loudspeaker systems for detailed instructions about the rigging of the
enclosures.

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1.3.4 Software
LA NETWORK MANAGER
Remote control and monitoring of amplified controllers.
SOUNDVISION
3D acoustical and mechanical modeling.
Software documentation
Refer to the LA NETWORK MANAGER video tutorial and the SOUNDVISION help.
Figure 1: Main components involved in loudspeaker system design and drive

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2LA4X AMPLIFIED CONTROLLER
2.1 Main features
2.1.1 Internal components
The core of the LA4X is a DSP engine driving four channels of amplification from four inputs. The LA4X also features a
flash memory for preset storage and management, high performance A/D-D/A converters for audio signals, a universal
SMPS (Switched Mode Power Supply) with PFC (Power Factor Correction), a front panel user interface, and a Fast
Ethernet device for network remote control.
2.1.2 Front and rear panels
Figure 2: LA4X front and rear panels
Status LED
1.
LED meters:
2.
LIMIT/CLIP level
audio level (-20, -10, -5 dB)
SIGNAL presence
LOAD presence
L-NET network control LED
3.
2x24 characters LCD display
4.
navigation/edition encoder wheel
5.
power/standby key and LED
6.
channel selection keys
7.
menu keys
8.
inward ventilation grill and foam filter
9.
PowerCON power supply connector
10.
outward ventilation grills
11.
SpeakON output connectors
12.
XLR analog and AES/EBU input connectors
13.
XLR analog and AES/EBU link connectors
14.
EtherCON L-NET network connectors
15.

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2.2 Signal processing and amplification
2.2.1 Signal inputs
The LA4X features four input connectors allowing it to receive four analog signals, four digital signals, or two analog
and two digital signals, depending on the input mode selected by the user (see section 3.4.1). This architecture also
allows digital-to-analog or digital-to-digital fallback.
Analog inputs
The LA4X can be fed with up to four balanced analog audio signals using XLR3 female input connectors ANALOG IN A
to ANALOG IN D (see Figure 2). Each analog input port is ESD protected.
The analog input panel also features four XLR3 male link connectors passively wired to the input connectors. They
allow transmitting the input signals to daisy-chained amplified controllers. Each analog link port is ESD protected.
To be processed by the DSP, the analog signal must be converted into a digital signal. For this purpose, the LA4X
amplified controller is fitted with four cascaded 24-bit A/D converters with a sampling rate of 96 kHz allowing an
encoding dynamic range of 128 dB.
AES/EBU digital inputs
The LA4X can be fed with up to four AES/EBU digital audio signals (transported in pairs) using XLR input connectors
AES/EBU IN A&B and AES/EBU IN C&D (see Figure 2).
Each AES/EBU input port is an XLR3 female connector. The audio signals can come from a digital mixing desk or a
digital audio network bridge compliant with the AES/EBU (AES3) or coaxial S/PDIF (IEC 60958 Type II) digital audio
standards. Each AES/EBU input port is ESD protected and transformer balanced.
The AES/EBU input panel also features two XLR3 male link ports actively connected to the input ports (with failsafe
relay in case of mains absence). They allow transmitting the input signals to daisy-chained amplified controllers. Each
AES/EBU link port is ESD protected and transformer balanced.
Each AES/EBU input port is equipped with a Sample Rate Converter (SRC) that has been selected to support a wide
range of input formats (16-24 bits/ 44.1-192 kHz). It converts any of them to the 24 bits/96 kHz internal format used by
the amplified controller. The SRC is a high-quality hardware component (140 dB dynamic range, THD+N<-120 dBfs,
strong input jitter attenuation) and provides constant propagation delay regardless of the input sampling frequency.
There is no external synchronization mode. The amplified controller’s clock always runs using its high-precision internal
quartz at 96 kHz. This ensures low jitter and high audio quality in live conditions (large cable lengths, large number of
amplified controllers) while preventing phase shift, as required for line source systems.
Digital domain benefits
Keeping the signal in the digital domain will provide the following benefits (with any digital mixing desk or any
audio network) compared to the analog signal distribution:
Better audio quality by removing one D/A - A/D cycle.
Better dynamics thanks to the digital links’ immunity to ground loops.
Optimized level chain by removing the risk of level misalignment between console and amplified controllers.
Digital signal refreshed at each amplified controller in a daisy-chain.
Improved maximum cable length. The LA4X has been tested with up to 305 m/1000 ft of 3 models of
AES/EBU rated cables: Belden®1696A, Klotz Cables®OT234H, and Sommer Cable®SC BINARY 234 (single
cuts, digital source signal running at Fs = 48 kHz).

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2.2.2 DSP architecture
The proprietary algorithms allow optimum performance and protection of each individual transducer of the
L-ACOUSTICS®systems for an even more natural, transparent and realistic sound experience.
The DSP engine is a 32-bit floating point DSP at 96 kHz sampling rate providing an enhanced dynamic range since
it does not generate calculation clips like a fixed point DSP.
A dedicated engineering approach combining IIR and FIR filters generates perfectly linearized phase curves and
significantly improved impulse responses.
The 4 x 4 matrix architecture offers flexibility for various system configurations.
A delay of up to 1000 ms can be set for each output channel.
The L-DRIVE transducer protection system offers advanced protection by simultaneously monitoring the excursion
and the temperature of the transducer.
With a complete factory preset library and the possibility to create additional user presets, the flash memory
provides a quick access to all the usual L-ACOUSTICS®speaker system configurations (refer to the PRESET
GUIDE).
Figure 3: Audio path parameters

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2.2.3 Power supply and amplifier section
LA4X is a “green” amplified controller that relies on a universal Switch Mode Power Supply (SMPS) s uitable for mains
from 100 to 240 V (±10 %). The SMPS features a Power Factor Correction (PFC) which maximizes the amplifier
efficiency and takes advantage of nearly 100 % of the electrical power available with a very high tolerance to unstable
mains. The PFC allows the LA4X to deliver as much power from a 10 A line as from a 16 A line on a conventional amp.
This represents a reduction of the electrical power requirements (cable gauge, power conditioning…) for substantial
savings.
The Class D amplification circuits ensure the LA4X energy-efficiency for minimal heat dissipation. LA4X delivers 4 x
1000 W RMS into 8 or 4 Ωwith record hold times. Besides the high raw power rating at 8 Ω, the ability to deliver
energy (power x hold time) yields the best performance from loudspeaker systems, especially in LF reproduction.
2.2.4 Speaker outputs
The LA4X features four SpeakON connectors for loudspeaker outputs.
2.3 Monitoring and control
2.3.1 User interface
The front panel user interface provides (see also Figure 2):
Real-time monitoring functionalities via the LED display (signals presence and level) and the LCD screen (system
parameters).
Instant access to navigation and parameters control using the encoder wheel and the six keys.
Operating instructions
Refer to section 4 for detailed operating instructions.
2.3.2 L-NET remote control network
The design of complex systems is made possible by the integration of the L-NET Ethernet-based network. Thanks to
its high speed data transfer protocol of 100 Mbit/s, up to 253 amplified controllers can be controlled and monitored in
real-time from LA NETWORK MANAGER software.
Multiple network topologies such as daisy-chain, star and hybrid are quickly and easily configurable for full flexibility in
the required system architecture. The computer running LA NETWORK MANAGER and the amplified controllers are
connected to each other using industry standard CAT5e U/FTP cables (or higher category) fitted with RJ45 connectors.
The LA4X connects to the network via the two EtherCON sockets located on its rear panel.
Operating instructions
Refer to the LA NETWORK MANAGER video tutorial for detailed operating instructions.
Third party management solutions
L-ACOUSTICS®provides SNMP support to facilitate the integration via third party control and monitoring
systems. As a certified member of the CRESTRON®and AMX®partner programs, L-ACOUSTICS®also provides
software modules allowing control integration into their automation systems.

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3INSTALLATION
3.1 Mounting
The LA4X is two rack units high (2U) and can be mounted in an EIA-standard 19”rack (see Figure 4). The four points
on the front panel are for rack mounting. Use the fixing material provided by the rack manufacturer to mount the
controller to the rack front rails.
Figure 4: LA4X dimensions
There is a risk of damaging the controllers during transport
During transport or while on tour it is essential that the controllers are rear supported in addition to the front
panel mounting.
Use the rear rack support brackets provided with the controller as shown in Figure 5.
Any mechanical damage to the controllers used in portable applications without rear support will not be
covered by warranty.
Figure 5: LA4X with rear rack support brackets

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3.2 Ventilation
To maintain a moderate operating temperature, the LA4X contains two fans providing front to rear airflow.
Instructions for proper ventilation
Install the controller in an open area so that the front and rear panels are located at a minimum distance of
30 cm from any external object or structure.
Ensure that the front foam filter is clean.
Do not block the front and rear ventilation grills on a controller.
If the controller is rack-mounted:
Do not block the ventilation grills with front or back panels or doors. If not possible, use a forced ventilation
system.
When stacking more than one controller in a rack, mount them directly on top of each other or close any
open space in the rack with blank panels.
3.3 Connecting to AC mains
3.3.1 AC mains specifications
Only connect the LA4X to an AC power outlet rated 100-240 V, 50-60 Hz, with the following current values:
20 A for 100-120 V, 10 A for 200-240 V.
The LA4X must be connected to a mains socket outlet with a protective connection to earth.
3.3.2 Three-phase circuit
Verify that each phase works, in particular the neutral one.
Balance the loads between the three phases.
Never try to reproduce a 230 V circuit connecting an apparatus to two live wires of a 120 V three-phase circuit.
Never try to reproduce a 200 V circuit connecting an apparatus to two live wires of a 100 V three-phase circuit.
3.3.3 Circuit breaker
Always interconnect a Class C thermal circuit breaker between the apparatus and the mains supply.
The circuit breaker current rating depends on the mains voltage rating as follows:
20 A for 100-120 V, 10 A for 200-240 V.
3.3.4 Electrical generator
Planning the power of the generator in kVA
Consider the LA4X will draw 10 A max from 230 V.
A typical generator has a power factor cos = 0.8 and should operate at 70 % load for good efficiency.
The kVA provision for one LA4X should therefore be: (10A x 230V) / (0.8 x 70%) = 4.1 kVA.

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3.3.5 Power cord
The LA4X is supplied with a removable power cord. One side of the power
cord is fitted with a PowerCON connector to connect to the MAINS panel on
the rear side of the controller, see Figure 6. The other side is fitted with a plug
to connect to mains.
The plug type depends on the country of use, according to the following table:
Table 1: Power cords for LA4X
Country
Plug type
Europe
CEE 7/7, 16 A / 250 V grounded
USA
NEMA 5-15, 15 A / 125 V grounded
Figure 6: LA4X MAINS panel
Plug connection
Strictly apply the specific safety regulations of the country of use.
Do not defeat the ground connection of the supplied power cord using an adaptor or any other methods.
If the plug does not match the local power outlet, it can be cut off and wired to a suitable plug (refer to the
LA4X maintenance manual –level 1).
Verify that the plug conforms to the specific voltage and current rating given in section 3.3.1.
3.3.6 Power consumption
The LA4X power requirements depend on the load impedance and the signal level as indicated in the following table:
Table 2: LA4X mains input power and current draw
Maximum output power
Mains input power and current draw
Load
Number of
driven channels
Power per
channel
1/3 max. output
power (-5 dB)
1/8 max. output
power (-9 dB)
IDLE
Standby
4 or 8 Ω
4
1000 W
7 A / 1600 W
3 A / 750 W
0.26 A /
60 W
< 0.1 A /
11 W
The current values are given for a mains rated at 230 V. Multiply by 2.3 for 100 V, 1.9 for 120 V or 1.15 for 200 V.
Output power references
A third of the maximum output power corresponds to the worst case scenario of a program source using highly
compressed music or pink noise with amplifier driven to clip level.
An eighth of the maximum output power corresponds to a loud music program with a small dynamic range and
9 dB of headroom (IEC standard power rating).
3.3.7 Example of heat power calculation
Connect a 4 Ω load to each output channel of the LA4X: each channel can now deliver a power of up to 1000 W.
Consider a standard use at 1/8 of full power (9 dB headroom): the power delivered per channel is then 1000 / 8 = 125
W, leading to a total power of 4 x 125 = 500 W for the LA4X.
According to Table 2 the LA4X power consumption is 750 W: the heat power produced is then 750 - 500 = 250 W
(difference between power consumption and output power).

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3.4 Audio and network cabling
3.4.1 Connection panels
The LA4X rear side features three panels for audio and network cabling, see Figure 7:
SPEAKER to connect loudspeakers.
SIGNAL to connect analog and/or digital (AES/EBU or S/PDIF) audio sources and link the signals to another
amplified controller.
L-NET to connect to a network and be remote controlled from LA NETWORK MANAGER software.
Figure 7: LA4X audio and network connection panels
The XLR connectors of the SIGNAL panel can transport analog or digital signals depending on the input mode selected
by the user for channel pairs AB and CD (the two selections can be different). The devices to connect to the IN
connectors are given in the following table (see also section 4.9.1 for input mode selection):
Table 3: Devices to connect to the IN connectors vs. input mode
Input mode AB
IN A (IN A&B)
IN B
ANALOG
analog audio source (1 channel)
analog audio source (1 channel)
AES/EBU
digital audio source (2 channels)
not used
Input mode CD
IN C (IN C&D)
IN D
ANALOG
analog audio source (1 channel)
analog audio source (1 channel)
AES/EBU
digital audio source (2 channels)
not used
Each LINK connector is wired to the corresponding IN connector and, thus, transports the same type of signal.
Digital audio source specifications
Standard AES/EBU (AES3) or coaxial S/PDIF (IEC 60958 Type II)
Sampling frequency 44.1, 48, 64, 88.2, 96, 128, 176.4 or 192 kHz
Word length 16, 18, 20 or 24 bits.

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3.4.2 Analog SIGNAL cabling
The eight XLR3 connectors of the SIGNAL panel (see Figure 7) are wired according to IEC 268: pin 1= shield,
pin 2= + signal, pin 3= - signal.
The four female XLR3 input connectors ANALOG IN A to ANALOG IN D can receive up to four analog signals (when
setting the analog input mode for channel pairs AB and CD). The headroom of the input circuits is high enough to
accept the maximum output level from virtually any line level signal source (up to 22 dBu).
In a daisy-chain layout, the four male XLR3 link connectors LINK A to LINK D feed the input signals to the next
amplified controller in the signal chain (see Figure 8). Each LINK connector is passively wired in parallel on the
corresponding IN channel. The input impedance is high enough (22 kΩ, balanced) to allow multiple parallel input
connections.
Balanced cables
Symmetrical (balanced) shielded cables are highly recommended as balanced signals are less sensitive to AC hum
and radio interference.
Unbalanced lines may add noise especially over long cable runs.
Figure 8: Daisy-chaining analog audio

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3.4.3 Digital SIGNAL cabling
The four AES/EBU XLR3 connectors on the SIGNAL panel (see Figure 7) are transformer balanced and wired
according to IEC 268.
The two female XLR3 input connectors AES/EBU IN A&B and AES/EBU IN C&D can receive up to four digital signals
(when setting the AES/EBU input mode for channel pairs AB and CD). The input format is AES/EBU (AES3) or coaxial
S/PDIF (IEC 60958 Type II).
In a daisy-chain layout, the two male XLR3 link connectors LINK A&B and LINK C&D feed the input signals to the next
amplified controller in the signal chain (see Figure 9). Each LINK connector is electronically buffered to allow daisy-
chaining any number of amplified controllers. It also features a failsafe relay to ensure wiring continuity in case of
amplified controller shutdown.
Cables for AES/EBU digital audio
The quality required for the XLR cables will depend on the cable length and the signal sampling frequency. As a
starting point, a standard balanced microphone cable of maximum length of 50 m (150 ft) can be used to
transport a signal of maximum sampling frequency of 48 kHz. Higher sampling frequencies may require reducing
the cable length since the signal attenuation in cables increases with the sampling frequency.
As AES/EBU certified cables provide smaller attenuation/length ratio, it is highly recommended to use them in
installations requiring long cable runs or high sampling frequency signals.
It is recommended to use single cuts of cable. Using several pieces will reduce performances.
In case an amplified controller shutdowns, the failsafe relay makes a passive connection between the AES/EBU
IN ports and the LINK ports to maintain continuity. However the signals are no longer refreshed for the next
amplified controller, so that the input cable and the link cable must be considered as a unique input cable with
regard to the maximum supported length.
In case of transmission losses, try to reduce the sampling frequency of the digital audio source. Moreover, as a
general rule, avoid using sources rated beyond 96 kHz as the maximum possible cable length will be reduced
while the additional information will anyway be cancelled by SRC to 96 kHz.
Figure 9: Daisy-chaining digital audio

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3.4.4 SPEAKER cabling
Loudspeaker system connection
Before connecting a loudspeaker system refer to the applicable user manuals for further instructions.
The four 4-point SpeakON®connectors on the SPEAKER panel (see Figure 7) are for loudspeaker connection. They
are wired as follows, see also Figure 10:
Top left SpeakON®connector
Top right SpeakON®connector
Pin 1+
Out 1+
Pin 1+
Out 3+
Pin 1 -
Out 1 -
Pin 1 -
Out 3 -
Pin 2+
Out 2+
Pin 2+
Out 4+
Pin 2 -
Out 2 -
Pin 2 -
Out 4 -
Bottom left SpeakON®connector
Bottom right SpeakON®connector
Pin 1+
Out 2+
Pin 1+
Out 4+
Pin 1 -
Out 2 -
Pin 1 -
Out 4 -
Pin 2+
not used
Pin 2+
not used
Pin 2 -
not used
Pin 2 -
not used
Figure 10: Output audio paths

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The table below describes the maximum number of enclosures a single LA4X amplified controller can drive.
Table 4: Maximum number of enclosures per LA4X
Technology
Loudspeaker
enclosure
Max number of connections
per output *
Max number of enclosures
per controller
Coaxial
5XT
4
16
8XT
2
8
Passive 12XT
1
4
Active 12XT
2
4
115XT HiQ
1
2
Constant
Curvature WST
ARCS®WIDE/FOCUS
1
4
ARCS®II
1
2
Variable Curvature
WST
KIVA KILO
2
8
KARA®
2
4
KUDO®
1
1
K2
1
1
Subwoofers
SB15m
1
4
SB18
1
4
* For passive loudspeakers, the value corresponds to the number of enclosures in parallel on the output.
For active loudspeakers, the value corresponds to the number of sections in parallel on the output.
3.4.5 L-NET cabling
The LA4X can be remote controlled over an Ethernet network (called L-NET) using LA NETWORK MANAGER
software (refer to the LA NETWORK MANAGER video tutorial).
To connect the LA4X to L-NET use the EtherCON connectors on the L-NET panel (see Figure 7). Each of the two
EtherCON connectors can be equally used as an IN or LINK connector.
Refer to the LA NETWORK MANAGER video tutorial for network setup (type of cables, physical connections,
network topology, etc.).