Purr-LUFS is a gain compensation plugin based on LUFS measurement, designed to deliver precise loudness compensation across any plugin, hardware, or effects chain. By ensuring that loudness levels remain consistent, it helps users make more objective decisions when comparing audio processing, eliminating the common bias toward louder sounds. This accuracy allows for a clearer evaluation of dynamic effects and tonal changes without the interference of perceived loudness differences.

A standout feature of Purr-LUFS is its innovative semi-lock mode, which activates when the compensated signal reaches a user-defined loudness threshold. This function maintains a stable loudness level during critical adjustments, such as compression or dynamic processing, ensuring a smooth workflow. Users can customize the threshold and compensation speed to suit their needs, whether aiming for subtle dynamics or broader audio changes. This flexibility makes Purr-LUFS particularly useful in mastering and fine-tuning scenarios, where maintaining tight loudness margins is essential.

For users of the Reaper digital audio workstation, Purr-LUFS offers enhanced integration through the Purr-Router plugin and a configuration script, simplifying complex routing setups. The Mac installer includes automatic setup for seamless channel routing, while Windows users can access standalone installers and scripts to achieve the same functionality. These tools streamline the use of Purr-LUFS in Reaper, making it easier to implement precise loudness compensation in various audio projects.