Loudness Contour v4.6.1 WiN MAC

Team BTCR | 28 November 2025 | 131 MB

Real-time equal-loudness Contour Shaping

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.