APU Software

Dynamics Optimizer

Adjust a whole recording's dynamics before export

Sale price $30.00 one-time · Regular price $40.00

APU Dynamics Optimizer helps you reshape the dynamics of a finished mix, podcast, or other recording. It analyzes the complete file before processing, so adjustments can account for the loudness range of the whole recording.

Choose a target loudness range and distribution: uniform, normal, the shape of the source, or another file as a reference.

The analysis lets the optimizer vary compression and expansion across the file’s loudness range. Listen while adjusting the target range, distribution shape, attack, and release, then export a 32-bit float WAV at the original sample rate.

Distribution modes: Uniform, Normal (with skew), Source-match, and Reference-match.
Loudness types: LUFS (Momentary, Short-term, Integrated), RMS, Peak, and True Peak.
Multi-channel: Supports stereo, surround, and Dolby Atmos® formats.
Weighting curves: K-weighting, ECMA-418, ITU-R 468, A-weighting, C-weighting.
Built-in limiter: Configurable look-ahead with Peak or True Peak mode.

The current release is a standalone application. It analyzes the file before processing begins.

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System requirements: macOS 10.14 (x64, ARM), Windows 10 (x86, x64), OpenGL 3.2.
Supported software formats: Standalone application.

Walkthrough

Open an audio file to analyze its loudness. The left histogram shows the source distribution; the right shows your target. The optimizer calculates compression and expansion settings to move the source toward that target.

Adjust the source percentiles to choose which part of the loudness distribution to use. The defaults use the same percentile range as LRA, leaving the quietest and loudest extremes outside the selected range.

Press the right arrow to continue.

Play the result and adjust it using controls shared with the Loudness Compressor. Use the play/stop buttons and seek slider to compare different parts of the file.

Export writes a new 32-bit float WAV at the original sample rate. The format can store samples above 0 dBFS, though you’ll still need to manage those peaks before fixed-point export or playback through a device that clips at 0 dBFS.

Configure the built-in limiter in the Limiter tab, or bypass it if you prefer to limit the audio after export.

Dynamics Shaping

The target distribution describes how you want loudness values spread across the target range. The optimizer uses it to calculate how much compression or expansion to apply at different levels.

Uniform

Uniform sets a flat target distribution across the selected loudness range, giving each part of that range equal weight.

Normal

Normal uses a bell-shaped target distribution. Adjust its skew to favor the louder or quieter end of the range.

Source

Source uses the shape of the analyzed source histogram, scaled to your target range. Choose it to narrow or widen the dynamics while keeping the original distribution shape as the target.

Reference

Reference uses the histogram from a second audio file as the target. Load it after analyzing the source. The target range starts at the corresponding reference range and updates when you change the source percentiles.

Measurement Modes

Choose the measurement that drives the optimizer: LUFS, RMS, Peak, or True Peak. Link channels to process them together, or split them for independent processing.

Momentary

Momentary measures loudness over a 400 ms window with K-weighting and channel weighting. It follows shorter changes in level and is the optimizer’s default measurement.

Short-Term

Short-Term measures loudness over a 3-second window, following longer changes in level. It uses the same K-weighting and channel weighting as Momentary.

Integrated

Integrated measures loudness over the measurement run, using K-weighting, channel weighting, and relative and absolute gating. It tracks the accumulated loudness rather than a fixed rolling window.

RMS

RMS measures signal level over an adjustable window, set to 150 ms by default. It does not apply K-weighting or channel weighting.

True Peak

True Peak estimates peaks between samples as well as sample peaks. It uses the configured block interval, which is 1 ms by default, for a fast detector response.

Peak

Peak measures sample peaks over the configured block interval, which is 1 ms by default. It does not estimate peaks between samples.

Limiter

The built-in limiter uses look-ahead to constrain gain changes and control output peaks. Choose Peak or True Peak detection, or bypass it to use a separate limiter after export.

Alternate Weighting

Alternate weighting curves change how much each frequency contributes to the detector. Use them to adjust how strongly bass, midrange, or high-frequency content drives the optimizer. Measurements with alternate weighting are no longer standard LUFS measurements.

The screenshots below show the curves in Loudness Contour. The optimizer applies them as zero-latency IIR filters in the detector path.

ECMA-418

ECMA-418 uses the outer- and middle-ear weighting curve from the ECMA-418-2 hearing model. It provides an alternative to K-weighting; it does not apply the standard’s full loudness model.

ITU-R 468

ITU-R 468 emphasizes the upper midrange, making the detector more sensitive to sibilance and other high-frequency content. Gain changes still affect the whole signal.

A-weighting

A-weighting reduces the influence of low frequencies. Use it when you want bass to contribute less to the loudness analysis.

C-weighting

C-weighting is flatter than A-weighting and retains more low-frequency energy in the detector.

Credits

Developed by APU Software, LLC with the following libraries:

JUCE (cross-platform audio and user interface framework)
Boost (header-only algorithms)
libebur128 (loudness measurements)
melatonin_blur (blur effects)
r8brain (sample rate conversion)

Demo video song credits:

Dan Phillipson - Feel The Drama, licensed via PremiumBeat.