APU Loudness Contour

Compatibility

• Supported Operating Systems: Supported OS: Mac, Windows
• RAM Requirements: License Method: Computer
• Disk Space: License Method: Computer 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. For Phon-dependent contours like ISO 226 and Fletcher-Munson, a reference SPL parameter allows you to select the desired phon level from 20-120 dB SPL. With Adaptive SPL enabled, this reference level automatically adjusts based on the incoming signal’s loudness level, allowing the contour to dynamically respond to program material. The plugin supports both linear phase and minimum phase filter types. Built-in makeup gain compensation is provided per contour and reference level, at the cart page. System requirements: macOS 10.14 (x64, ARM), Windows 10 (x86, x64), OpenGL 3.2. Supported software formats: Standalone application, VST, AU, AAX (Pro Tools 11+) . Use Cases Understanding where APU Loudness Contour excels can help you achieve better, faster results. The examples below highlight real-world scenarios. Sidechaining with Perceptual Emphasis Insert APU Loudness Contour before a compressor’s sidechain input with a positive contour weight . The detector now prioritizes what listeners perceive most, enabling smoother, more musical gain reduction-especially on dense mixes. Enhancing Dialog for Clarity Speech intelligibility relies heavily on the 1-4 kHz range. Applying a broadcast-oriented contour with moderate positive weight emphasizes these key frequencies, improving clarity on laptops, phones, and TVs. Contour Types One of the key features of this plug-in is its support for a wide variety of loudness contours. Each contour models a specific equal-loudness perception curve used across audio metering, broadcasting, psychoacoustics, or legacy equipment standards. The contour weight parameter allows fine-grained control over each model, either enhancing or inverting the effect. This enables creative spectral shaping, perceptual balancing, or subtle coloration. K-weighting K-weighting is a filtering model defined in ITU-R BS.1770 for loudness normalization, emphasizing frequencies around 2-4kHz to approximate human hearing sensitivity in broadcast contexts. The K-weighting filter is used by the ubiquitous LUFS metering standard, which is widely adopted in the music and broadcast industries. ECMA-418 ECMA-418 is a modern standard for perceptual frequency weighting, designed to reflect human hearing sensitivity in typical listening environments. Unlike legacy curves such as A- or C-weighting, ECMA-418 is based on contemporary psychoacoustic research and aligns more closely with perceived loudness in real-world conditions. Within APU Loudness Contour, the ECMA-418 filter provides a perceptually relevant loudness contour that can be finely adjusted via the contour weight control. This makes it particularly useful for ta Skip to content APU Software Open navigation Products Meter Leveler Compressor Optimizer Limiter Spectrum Contour TrueGain Research Loudness Targets Filter Design Results Plugin Analysis Company Blog Newsletter Testimonials Manuals Download Cart APU Software APU Loudness Contour Real-time equal-loudness contour shaping $40.00 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. For Phon-dependent contours like ISO 226 and Fletcher-Munson, a reference SPL parameter allows you to select the desired phon level from 20-120 dB SPL. With Adaptive SPL enabled, this reference level automatically adjusts based on the incoming signal’s loudness level, allowing the contour to dynamically respond to program material. 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. Add to Cart ($40.00) Download (30-day Trial) Note: Existing customers can apply their loyalty discount at the cart p