Line Array Calculator III v3.5.0 (Windows)

Note: this is an old version. The current version is: Line Array Calculator III v3.9.0 (Windows). ×

Last Updated: août 04, 2023


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.

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 B28
  • VTX V25-II / VTX V25-II-CS
  • VTX V20
  • VTX S25
  • VTX S28
  • VTX G28

New in 3.5.0:

New Features and Improvements:

Added support for the following products:

  • VTX B28, VTX B28 SB, VTX B28 GND, VTX B28 VT, VTX A12 BP and the VTX V20 BP

Improved mechanical calculations for Ground Stacked Arrays:

  • New safety checks have been implemented to check stability for Ground Stack Arrays.
  • LAC takes into consideration the number of cabinets, cabinet angles and accessories used to check stability. The application can warn when a stack is potentially unstable or above the mechanical limit of a given configuration.

Virtual Plane:

  • A new plane type has been added. The new virtual plane is similar to an architectural plane but it does not block predicted coverage.
  • Architectural planes are now displayed with a solid line and virtual planes with a doted line.

Right-click options for the QR code:

  • A right-click menu has been added to allow copying the QR code to the clipboard. An option to save the QR code is also available. File types formats PNG, JPEG, Bitmap and GIF.

Distance Vs Angle switch:

  • The Distance Vs Angle selection switch has been moved from the Projects Details panel to the venue page. This allows quicker access to this functionality. The Project Details panel can now be accessed from the main hamburger menu.

Recent Files right-click menu:

  • A right-click menu is now available for items listed in the Recent Files section.
  • The new menu includes the following options: Show in Folder / Remove from Recent Files / Remove All from Recent Files.

Color resolution for SPL Mapping:

  • 3dB and 6dB step options have been added to SPL mapping mode to better help visualize coverage. The new options are available in all modes including Distributed Subwoofer Arrays.

Application Options improvements:

  • The Application Options panel is now a floating window, not a full-screen panel.
  • An “Apply” button has been added to allow applying changes without closing the window. This is especially useful when trying to A/B settings like Air Parameters.
  • A option is now available to switch auto calculate ON and OFF.

Coordinate and SPL information tool tip:

  • All view ports now have a tool top that follows the cursor indicating the x/z coordinates of the cursor.
  • In Mapping Mode, a left click brings up the cursor and in SPL mapping mode, the predicted SPL is also indicated.

Bug Fixes:
  • LAC was generating the incorrect QR code for some regions.
  • The Print Preview PDF page was not generated correctly on computers with HiDPI displays.
  • The angle for the top speaker of a ground stacked A8 or A12 array is now correctly set to 10° not 0°.
  • The “Ray Shadowing” check-box option is now saved to the file.
  • Fixed a problem where some LAC popup windows could not be moved.
  • Changing from A8 to A12 and vice-versa does not reset the array angles.
  • The Y axis has been changed to Z axis to better represent height.
  • Ground Subwoofer Array has been renamed to Distributed Subwoofer Array
  • The venue zoom position is now saved to file.
  • Fixed several issues related to HiDPI displays.





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