APU Software Loudness Contour v5.7.1 -BLiZZARD

Loudness Contour is a real-time equal-loudness filter plugin for Windows that lets you shape frequency response according to human perception. It includes standard contours such as ISO 226 (2003 and 2023), Fletcher-Munson, K-weighting, A/C-weighting, ECMA-418, and ITU-R 468. Each curve is normalized to 0 dB at 1 kHz and has a dedicated weight control that scales the response from flat (0%) to inverted (negative). For ISO 226 and Fletcher-Munson, you can adjust the reference level from 20 to 120 dB SPL with smooth interpolation between phon curves. Choose between linear phase and minimum phase filter types. Built-in makeup gain, calibrated via pink noise LUFS, compensates for level changes per contour and reference level, with extra output gain for manual tweaks. A real-time spectrum analyzer offers configurable FFT size, window type, bucket width, and time averaging, plus linear, logarithmic, or musical note frequency scales, auto-zoom, and custom dB range. It suits hobby producers and mixing engineers who want perceptual loudness correction, equal-loudness monitoring, or creative tonal shaping in FL Studio, Ableton Live, or Logic Pro on Windows.