Mercurial Tones Tether is an elastic loudness leveler from Mercurial Tones designed for modern music production, mixing, and audio processing. Instead of relying on traditional threshold, ratio, and makeup-gain controls, Tether lets you define a target loudness level and automatically moves the signal toward that target in real time.

The plugin works in both directions. Louder sections can be gently reduced while quieter sections are lifted toward the selected target, providing a simple way to achieve more consistent levels while retaining the character and dynamics of the original performance.

Tether includes Peak, RMS, and K-Weight detection modes for adapting the leveling response to different types of audio material. Its visual display provides real-time traces of the original and processed signal, helping you monitor how the leveler is affecting the audio.

The Pull section provides independent Low and High correction controls, together with Focus, Speed, Range, Mix, and Trim parameters. Tether's Natural Engine provides program-dependent processing and includes dedicated source modes for Allround, Drums, Bass, and Vocal material.

Tether also features a built-in Floor section with a soft gate. When the signal drops below the selected floor, upward correction is reduced, helping prevent quiet breaths, room noise, bleed, and other low-level details from being unnecessarily amplified. The smooth knee provides more natural transitions during processing.

AI Assist provides a convenient starting point for users who want an automatically suggested setup. After analyzing a representative section of audio, it can suggest settings for Target, Floor, Pull, Focus, Speed, and Range. These settings can then be adjusted manually to suit the individual track or mix.

Key features include elastic two-way loudness leveling, target-based level control, Peak, RMS and K-Weight detection, independent Low and High Pull controls, multiple Focus modes, a Natural Engine, dedicated source modes, a built-in soft-floor gate, predictive gain protection, 10 ms lookahead, phase-coherent dry signal delay, Mix control, input and output trim, real-time loudness visualization, and AI Assist.

Mercurial Tones Tether is available in VST3, AU, and Standalone formats and supports Windows and macOS systems. It supports sample rates from 44.1 kHz to 192 kHz and can operate with mono and stereo audio.

Tether can be used for vocals, drums, bass, instruments, and other audio material where consistent loudness is required. Its combination of target-based leveling, dynamic control, soft-floor processing, and AI-assisted setup makes it a flexible tool for modern audio production and mixing workflows.