APU Software


Latest installers and user manuals.

Loudness Compressor v1.9.15

Choose your operating system to download the latest installer below.

MacOS Windows User Manual

The user manual above is also available on the live docs site.

System requirements: macOS 10.14 (x86, x64, ARM), Windows 10 (x86, x64), OpenGL 3.2.
Supported plug-in types: VST, AU, AAX (Pro Tools 11+).

Loudness Meter v1.9.15

Choose your operating system to download the latest installer below.

MacOS Windows User Manual

The user manual above is also available on the live docs site.

System requirements: macOS 10.14 (x86, x64, ARM), Windows 10 (x86, x64), OpenGL 3.2.
Supported plug-in types: VST, AU, AAX (Pro Tools 11+).

Release Notes

Version 1.9.15

  • Replace look-ahead dial w/slider (compressor)
  • Fix sidechain layout (compressor)
  • Improve dials layout (compressor)
  • Fix notification coloring

    Version 1.9.14

  • Drag & drop file open support (meter)
  • Look and feel improvements

    Version 1.9.12

  • Lots of cosmetic improvements

    Version 1.9.11

  • Improve visualization rect cropping glitch
  • Update tab for checking latest product versions
  • Additional minor fixes and improvements

    Version 1.9.10

  • Fix transfer function visualization for gate (compressor)
  • Detect all loudness types for file i/o (meter)
  • Improve quick-access layout
  • Improve panel and other layout elements

    Version 1.9.9

  • Fix look-ahead behavior in some cases (compressor)
  • Transparent statistics group (meter)

    Version 1.9.8

  • Improve visualizations

    Version 1.9.7

  • Logo update

    Version 1.9.6

  • Add Soft Limiting dynamics type (compressor)
  • Extend source/target min to -70.0 to match LUFS gate
  • Adjust default range/threshold settings

    Version 1.9.5

  • Fix license key displaying incorrectly (compressor)

    Version 1.9.4

  • Add makeup/bypass/gate low-level modes for source:target dynamics type (compressor)
  • Panel texture and shadowing improvements

    Version 1.9.3

  • Update default theme
  • Various minor fixes

    Version 1.9.2

  • Fix single-value slider thumb offset, improve coloring

    Version 1.9.1

  • User interface improvements
  • Revert maximum loudness range change, causing issues with sliders

    Version 1.9.0

  • Expand maximum loudness range
  • Improve Atmos histogram alignment
  • Fix histogram bucket range end text

    Version 1.8.9

  • Fix auval validation failure
  • Minor fixes and improvements

    Version 1.8.8

  • Transfer function raster type (compressor)
  • Fix layout issues, give manual range its own row
  • Exclude threshold from manual range
  • Center histogram buckets for channel-linked

    Version 1.8.7

  • History and histogram rendering quality improvements
  • Fix settings tab parameters not updated in some cases

    Version 1.8.6

  • Add Save as Default preset/theme manager buttons
  • Fix missing tooltips for preset/theme manager buttons
  • Fix histogram hold toggle location in visualization tab

    Version 1.8.5

  • Fix missing threshold for alternate dynamic types in peak modes (compressor)
  • Minor gui improvements

    Version 1.8.4

  • Reduced CPU usage for LUFS calculations
  • Reduced CPU usage during source/target range changes
  • Switch from bucket count to bucket size for consistency
  • Support manual BPM configuration in settings tab
  • Flip histograms to be vertical
  • Minor fixes and improvements

    Version 1.8.3

  • Possible fix for OpenGL compatibility issues
  • Add error message when OpenGL >= 3.2 is not available

    Version 1.8.2

  • Switch OpenGL from compatibility profile to core profile
  • OpenGL related performance optimizations
  • Layout improvements, auto/manual range configuration, show/hide thresholds (meter)

    Version 1.8.1

  • Learn function for source/target ranges

    Version 1.8.0

  • Fix default preset/theme migration
  • Cleanup button corners

    Version 1.7.12

  • Various user interface improvements

    Version 1.7.11

  • Improvements to visualization / threshold rendering (meter)

    Version 1.7.10

  • Improvements to parameter defaults
  • Display ratio as source/target instead of target/source

    Version 1.7.9

  • Improve texture compatibility

    Version 1.7.8

  • Relocate side-chain to fix layout glitch
  • Fix normal color slider thumb contrast
  • Tweaks to panel texture
  • Improve performance with automation w/editor open
  • Fix potential deadlock during rendering

    Version 1.7.7

  • Add show thresholds option (compressor)
  • Various minor fixes and improvements

    Version 1.7.6

  • Fix panel rendering when delta field is disabled

    Version 1.7.5

  • Style toggle buttons
  • Improved panel texturing

    Version 1.7.4

  • Increase the font size

    Version 1.7.3

  • Loudness axis ticks/labels
  • Enable minimize/maximize window buttons for standalone
  • Fix loudness range text box editing (compressor)
  • Fix ordering on delta histograms (compressor)
  • Quick-access manual range slider when auto-range disabled (compressor)
  • Exclude threshold from manual range, except when changing (compressor)

    Version 1.7.2

  • Fix A/B buttons showing over zoomed visualization (compressor)
  • Fix some text elements not fully displaying
  • Fix visualization area clicks not always registering
  • Fix minor layout issues
  • Textured panel background shader

    Version 1.7.1

  • Textured meters
  • Quick-access buttons for auto-range & breath residual (compressor)

    Version 1.7.0

  • User interface cleanup

    Version 1.6.16

  • Simplify switching between raster types and dynamics types

    Version 1.6.15

  • Support Dolby Atmos/SMPTE channel orderings

    Version 1.6.14

  • Fix sidechain output! (compressor)

    Version 1.6.13

  • Improve license input visibility (compressor)

    Version 1.6.12

  • Small improvements to context sensitive help (compressor)

    Version 1.6.11

  • Disable output gain during bypass! (compressor)

    Version 1.6.10

  • Support traditional compression/expansion configuration types in addition to source => target (compressor)

    Version 1.6.9

  • Knobs, dry/wet, output gain (compressor)
  • Aesthetic improvements

    Version 1.6.8

  • Support for Pro Tools
  • Support mouse wheel for combo-boxes
  • Condense user interface a little

    Version 1.6.7

  • Support for macOS Mojave (10.14)

    Version 1.6.6

  • Output types: Standard, Bypass, Delta (compressor)
  • Fix output offset in extreme cases (compressor)

    Version 1.6.5

  • Improved preset save
  • Fix missing source knee threshold drawing
  • Fix missing font characters

    Version 1.6.4

  • Default manual reset, with a reasonable general-purpose default loudness range
  • Default breath residual mode enabled

    Version 1.6.3

  • Aesthetic improvements

    Version 1.6.2

  • Fix mono channels when using stereo loudness types

    Version 1.6.1

  • Fix discontinuities at compression curve extremes (compressor)

    Version 1.6.0

  • Presets & Themes management
  • A/B comparison buttons (compressor)

    Version 1.5.2

  • Minor graphical improvements

    Version 1.5.1

  • Fix Logic Pro validation failure
  • Darken the shading a bit outside the visualizer HUD

    Version 1.5.0

  • Improve/fix breath residual feature (compressor)

    Version 1.4.9

  • Support loading from file for analysis (meter)

    Version 1.4.8

  • Many cosmetic & visualizer improvements, configurable bit-depth

    Version 1.4.7

  • Fix mutex double-lock freeze on latency change in Cubase (compressor)

    Version 1.4.6

  • Additional optimizations and re-fix plug-in resize

    Version 1.4.5

  • Fix FLStudio crash on startup (meter)

    Version 1.4.4

  • Fix plug-in resize AU JUCE bug

    Version 1.4.3

  • Reduce overlay redraw overhead

    Version 1.4.2

  • Reduce CPU usage when editor is closed (meter)

    Version 1.4.1

  • Fix rare crash due to text rendering race condition
  • Fix settings apply/discard buttons sometimes enabled unnecessarily
  • Apply look and feel to standalone application audio settings dialog
  • OpenGL performance improvements

    Version 1.4.0

  • Improve sound quality (compressor)
  • Improve performance (especially meter)
  • Smoother history rendering
  • Improve various minor visual elements
  • Fix stereo RMS reset in certain cases
  • Support offline license activation (compressor)

    Version 1.3.1

  • Improve performance via more reasonable default block size (meter)
  • Minor aesthetic improvements

    Version 1.3.0

  • Fixes & improvements to stereo and integrated LUFS
  • Fix for combo-boxes closing themselves.
  • Fix for trial/license activation glitches while offline (compressor).

    Version 1.2.2

  • Updated EULA: Added a commitment to provide unprotected builds in the event the business ceases operations or goes offline, ensuring long-term access to the software for licensed users.

    Version 1.2.1

  • Support LRA, improvements to peak/min history (meter)

    Version 1.2.0

  • Initial release of APU Loudness Meter
  • Bug fixes and quality improvements (compressor)

    Version 1.1.0

  • Fix knee boundary artifacts (compressor)

    Version 1.0.4

  • Eliminate visual discontinuity during history length increase (compressor)
  • Improve target range behavior (compressor)

    Version 1.0.3

  • Reduce pixel shader artifacts (compressor)

    Version 1.0.2

  • Fix license status text not updating in certain cases (compressor)

    Version 1.0.1

  • Enable sandbox safe for audio unit compatibility (compressor)

    Version 1.0.0

  • Initial release of APU Loudness Compressor


This software was developed by APU Software, LLC and is available as VST (windows x64/x86, macOS universal), Audio Unit (macOS universal), Pro Tools (windows x64/x86, macOS universal), or Standalone Application. The software libraries below are utilized for portions of the software:

  • JUCE (cross-platform audio and user interface framework)
  • Boost (header-only algorithms)
  • libebur128 (loudness measurements)

Demo video song credits:

  • Annasara - A Lifetime Rolls By, licensed via Audiio.

VST compatible