实时等响度滤波器 APU Software Loudness Contour v4.6.1 [WiN, MacOSX]

Team BTCR | 131 MB

APU 响度曲线（APU Loudness Contour）是一款实时等响度滤波器，可对多种听感响度曲线进行精准控制，涵盖 ISO 226（2003 版与 2023 版）、弗莱彻 – 芒森（Fletcher-Munson）、K 加权、A/C 加权、ECMA-418 及 ITU-R 468 等标准曲线。

每条曲线均以 1 千赫兹（1 kHz）频率点为 0 分贝（0 dB）进行归一化处理，并配有专属的 “曲线权重” 参数 —— 可将频率响应向正向或负向缩放。权重设为 0% 时，频率响应呈平直状态；负权重则会使曲线反向。其中，ISO 226 与弗莱彻 – 芒森曲线支持 20 分贝声压级（dB SPL）至 120 分贝声压级（dB SPL）的可变参考声压级，且在不同方（phon）曲线间支持平滑插值过渡。

该插件同时支持线性相位滤波器与最小相位滤波器两种类型。针对每条曲线及对应参考声压级，插件均内置了补偿增益（makeup gain）功能，且已通过粉红噪声 LUFS 测量完成校准。启用该功能后，补偿增益会按对应增益量对整条曲线的响应进行偏移调整。此外，插件还提供额外的输出增益控制，供用户手动精细调节。

插件内置功能全面的实时频谱分析仪，支持配置 FFT 大小、窗口类型、频段宽度（bucket widths）与时间平均参数。频率可视化可在线性刻度、对数刻度或音符刻度间切换，同时具备自动缩放与自定义分贝范围功能。

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.