HoRNet ELM 128 is a precise metering plugin designed to meet the EBU R128 loudness standard. It offers five distinct loudness measurements including momentary, short-term, integrated, dynamic range, and true peak, providing comprehensive monitoring for audio professionals. The plugin uses LUFS (Loudness Units Full Scale) to measure loudness, which applies a pre-emphasis filter to reflect human hearing characteristics more accurately than traditional decibel measurements.

Originating from broadcasting practices, this metering tool helps reduce the perceived loudness differences between various audio programs. It features a real-time normalization function that automatically adjusts gain to ensure the signal does not exceed the recommended -23 LUFS, making it ideal for maintaining consistent volume levels across different content types such as films or television shows.

Each of the five measurement modes uses different integration times and approaches: momentary captures loudness over 400 milliseconds, short-term over 3 seconds, and integrated reflects the overall loudness while excluding long silences or extreme peaks. The dynamic range meter shows the loudness range of the program, and the true peak meter uses oversampling to accurately detect inter-sample peaks, ensuring precise peak level monitoring.