APU Software releases Loudness Contour Plugin

APU Software has announced the release of APU Loudness Contour, an equal-loudness contour plugin-in and standalone application supporting ISO 226, Fletcher-Munson, K-weighting (LUFS), ECMA 418, ITU-R 468, A-weighting and C-weighting loudness contours. APU Loudness Contour APU Loudness Contour is a real-time equal-loudness filter that offers precise control over a wide range of perceptual loudness contours, including ISO 226 (2003 & 2023), Fletcher-Munson, K-weighting, A/C-weighting, ECMA-418, and ITU-R 468. Each contour is normalized to 0 dB at 1 kHz and includes a dedicated contour weight parameter, allowing you to scale the frequency response in both positive and negative directions. A weight of 0% results in a flat response, while negative weights invert the contour. ISO 226 and Fletcher-Munson curves support variable reference levels from 20 dB SPL to 120 dB SPL, with smooth interpolation between phon curves. The plugin supports both linear phase and minimum phase filter types. Built-in makeup gain compensation is provided per contour and reference level, calibrated using pink noise LUFS measurements. When enabled, makeup gain offsets the entire contour response by the corresponding gain amount. Additional output gain is available for manual fine-tuning. A comprehensive real-time spectrum analyzer is included, featuring configurable FFT sizes, window types, bucket widths, and time averaging. Frequency visualization can be switched between linear, logarithmic, or musical note scales, with auto-zoom and custom dB range options. Pricing & Availability APU Loudness Contour is available for macOS and Windows in VST3, AU and AAX plugin formats for the introductory price of $30. A trial version is available. YouTube.com/watch?v=qCHEZrBuGM8 Read More