Line Array Calculator 3
Predict Your Design


Line Array Calculator 3
Line Array Calculator (LAC) is a simulation software intended for the design and prediction of JBL VTX Line Array systems and their acoustical performance. In addition, you can also use the software with flown and ground stacked JBL VTX Subwoofer Arrays. Beyond just acoustical prediction, you can use Line Array Calculator for mechanical validation and the calculation of all weight limits and safety warnings for JBL VTX Systems.

Line Array Calculator’s Enhanced Acoustical Modeling includes color SPL mapping, 0dB Isobar and SPL attenuation modes with frequency response and SPL based on JBL’s VTX DSP presets. With it, you can place up to 8 virtual microphones in the venue for accurate position-dependent response prediction. Additionally, the built-in Calculator is now updated with subwoofer modeling, allowing you to generate subwoofer delay values for electronic subwoofer array steering (EDS).

Mechanical Validation of single and dual-point array suspensions can now include weight limit calculations in real time. Array statistics are calculated that include array size, depth and weight and array design factors are calculated, that you can use to design arrays that meet local safety and regulation limits. Safety warning messages can also be provided when an unsafe configuration is selected.

Updates found in the new Line Array Calculator 3 include: a completely redesigned UI that’s both more intuitive and combined with an unlimited number of planes; more virtual measurement probes; frequency response averaging of multiple virtual measurements; and a brand-new subwoofer prediction mode. Multiple subwoofer clusters can now be entered into the display window and the software will predict broadband polar response of the entire array. With Line Array Calculator 3, system designers can now make more informed decisions about how subwoofer arrays should be placed in venues and aid in the optimization of these arrays for their best possible performance.
  • Acoustic prediction of JBL VTX Line Array Systems as well as flow and ground stacked subwoofer arrays
  • Support for 8 virtual measurement probes for predicting the frequency response of an array
  • New subwoofer prediction mode for acoustic prediction of ground stacked arrays with the ability to generate delay values for Electronic Delay Steering (EDS)
  • Built-in array optimization tools including the new JBL Array Size Compensation (ASC) filter
  • Full integration with JBL’s Performance Manager control software
  • Mechanical validation of arrays in real-time for single and dual-point suspension modes
  • Array statistics including array size, depth, weight and design factor
  • 3D DXF Export support
  • EASE GLL configuration export support


JBL Array Link is a mobile companion app that works in conjunction with JBL’s latest LAC-III software to assist technicians deploying JBL VTX Series line array systems. Array Link uses a QR code system to transfer all array mechanical information from the main LAC-III application to a mobile phone – this transfer is done directly and in real time without the need of internet connection. All relevant rigging information and options are presented in an easy-to-understand layout.

The application is compatible with iOS® and Android and can be obtained from the respective App Stores.

Line Array Calculator 3.4.0

Offering accurate predictions in an efficient and time-conscious manner, the JBL Line Array Calculator platform supports all VTX line array products and is a critical link in the system design and prediction process.

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System Requirements

Supported Operating Systems:
  • 64-bit versions of Windows 7, Windows 8.1 or Windows 10

Minimum Performance Guidelines:
  • CPU: 64 bit dual core @ 2.0GHz or better
  • Memory: 2GB

LAC3 supported devices:
  • VTX A12
  • VTX A12W
  • VTX A8
  • VTX B18
  • VTX V25-II / VTX V25-II-CS
  • VTX V20
  • VTX S25
  • VTX S28
  • VTX G28

New in 3.4.0:

New Features:
  • Compatibility support with ArrayLink Version V1.2 and Performance Manager V2.6.5
  • Venue Page Improvements including the ability to export and import venue geometry
  • Improvements in Ground Stack Subwoofer Mode
  • New “Suspension Mode” and “Suspension Point” option added to the configuration page
  • New settings panel in Mapping mode
  • Automatic Circuit Grouping
  • Added Amplification Mode selection for V20, S25 and S28
  • Line Array Control Panel Improvements including the new Master Reset Button
  • Improvements in Ground Stack Array Mode
  • Improvements in SPL Mapping page

Bug Fixes:
  • User preferences (like Unit selection) are preserved after installing a new version of LAC.
  • A12W can now be placed above A12 if needed.
  • Circuit grouping colors have been added back to Ground Stack Array mode.
  • Addressed several issues related to the QR code export for ArrayLink. Depending on the Windows localization settings, LAC would sometimes send the incorrect information to ArrayLink.
  • The VTX V20 DF can now be used as a standalone pull-back frame for V25-II systems.
  • Pull-back has been removed for compression style systems (V20 and V25-II-CS) since array geometry is not quarantined when a pull-back is used.
  • Updated V20 Bi-Amp directivity and frequency response data.
  • The cabinet connected to the array frame or an adapter frame now shows AF (or DF) in the angle box.
  • A new drop-down menu is available for the A12 in the configuration page to allow for reversing the Array Frame independent from the extension bar.
  • The LAC default (start) configuration has been adjusted to include six cabinets.

New in 3.3.1:

Bug Fixes and Improvements:
  • The auto-calculate functionality for ground stack arrays has been improved for venues that have audience areas above the array
  • The angle position of the top enclosure of a ground stack array is now saved correctly to the venue file.
  • The exact position of a ground stack array is now correctly saved to the venue file.
  • Addressed A12 / A12W stacking logic for ground stacked A12 arrays.
  • Addressed a problem where the ground stack array frame was not refreshed correctly after closing and reopening a file.
  • The LACP filters for ground stack arrays are now applied in the correct order.
  • Addressed an issue related the VTX V20 DF when used as pull-back for V25-II-CS systems.

New in 3.3.0:

New Features:
  • Added support for: VTX A8 Base Plate and VTX A8 Mini Frame
  • Added support for ArrayLink version 1.1
  • Improvements in Ground Stack Array mode
  • Improved Zoom functionality in Venue and Mapping modes
  • Added copy/paste venue geometry functionality
  • Added EASE GLL export functionality
  • Replaced print preview functionality with direct PDF export
  • Added SPL coverage shadowing
  • General improvements in Venue Page including the use of tab key to create planes

Bug Fixes:
  • Improved mechanical calculations
  • Fixed the -1dB Array Size Compensation filter position
  • Circuit grouping improvements. When speakers are grouped, only one speaker selection drop-down is shown
  • Addressed dependencies in speaker and accessory weights (A12, A12W, A12-AF, A8, A8-AF)

New in 3.2.1:

Bug Fixes:
  • Corrected wrong Top/Bottom elevation in Print Preview page
  • Updated the frequency response curves for the VTX B18
  • Updated the VTX A8 AF and VTX A8 AF EB weight

New in 3.2.0:

New Features:
  • Added support for: VTX A8, VTX B18, VTX A8 AF, VTX A8 SB
  • Added support for ArrayLink version 1.0.3
  • Added System Selection drop-down menu in mapping mode
  • Extended the LAC calculation frequency up to 16kHz
  • Added listening height adjustment in the Venue page

Bug Fixes:
  • Rearranged weight gages in Configuration page
  • Several improvements in Ground Stack Array mode
  • Cardioid subwoofers are now displayed with a fill color for differentiation
  • Suspension Details drawing auto-scales to best fit the designed array
  • Removed extra Gain and LACP buttons from grouped circuits
  • Several UI performance improvements. Opening files in now much faster
  • Addressed several minor issues related to the VTX A12 Suspension Bar
  • Added the Suspension Bar to the DXF export

New in 3.1.3:

New Features:
  • Calculation performance improvements:
    • The LAC-3 calculations engine is now multi-threaded and can take full advantage of multi-core CPUs
    • Depending on the computer’s CPU type, up to a 10x performance improvement can be observed

Bug Fixes:
  • Addressed an issue related to the front/rear weight calculations. In some cases the front and rear weights were reversed
  • Addresses a DXF export issue related to the VTX A12W
  • Virtualization improvements - LAC-3 can now run in a virtual machine
  • Addressed an issue related to the VTX V20 angles when used in compression mode

New in 3.1.2:

Bug Fixes:
  • Addressed a formatting issue related to Windows language settings and the DXF export. In some case the DXF file was not formatted correctly
  • Corrected VTX S25 DXF file (the VTX S25 size was incorrect)
  • Changed LAC-III to be checking for new updates automatically
  • Addressed an issue related to the frequency probes. In some cases the position of the frequency probes could not be changed
  • Addressed an issue where the "Print" command would delete the project name
  • Added a subwoofer spacing selection in the Application Options menu. Subwoofer spacing can be defined as "Center to Center" or "Edge to Edge"

New in 3.1.0:

New Features:
  • Support for the new VTX A12W
  • Added ground stack support for VTX A12 systems
  • Added VTX V20 BA (Bi-Amp) option in the speaker type drop-down menu
  • Added Auto Update function
  • Added a new “Export to DXF" function
  • Several bug fixes

New in 3.0.3:

New Features: Bug Fixes:
  • Addressed an issue related to the generation of Array Statistics values
  • Addressed an issue related to subwoofer spacing and switching from metric to imperial and back
  • Improved color mapping (now in 6dB steps) in Subwoofer Mode for better coverage representation

New in 3.0.2:

New Features:
  • Added support for the VTX A12 Suspension Bar to be used as an array frame for VTX A12
  • Added support for JBL’s ArrayLink mobile application
  • Improved integration with Performance Manager Version 2.5

Bug Fixes:
  • Several visual UI improvements
  • Performance optimizations
  • UI scaling issues on HiDPI displays
  • Improved subwoofer mode

New in Beta 2:

New Features:
  • Added support for the VTX A12 Suspension Bar for pullback applications

Bug Fixes:
  • Addressed several UI scaling issues on HiDPI displays
  • Addressed several issues related to switching units (Imperial Vs Metric)
  • Addressed a subwoofer spacing issue related to ground stack subwoofer arrays
  • Added dB and Frequency scales to the measurement graph
  • Average trace improvements in measurement graph window
  • Addressed "Min Pull Back Load" display issue for compression style system
  • The position of the frequency response probes can now be changed
  • The main LAC-III windows can be used even when the LACP panel is open
  • Compatibility improvements with Performance Manager version 2.4.1
  • Several visual UI improvements

New in Beta 1:

New Features:
  • Initial Beta release