HoRNet Sybilla Pro

Sybilla Pro 1.2.0 is available, this update is free for owners of the plugin and includes:

•  Added Apple Silicon M1 support
• Fixed GUI being too small on windows with hi dpi monitors
• Removed 32bit support

Precise and complete de essing control

Sybilla Pro: Precision De-Essing with Multi-Filter Control

Sybilla Pro is not your typical de-esser plugin. Instead of relying on a single narrow band or simple high-frequency detection, it offers a unique approach with eight independent, tunable filters, giving you surgical control over sibilant frequencies. This design allows you to isolate and reduce sibilance more intelligently and effectively than traditional solutions.

Unlike most de-essers that rely on static frequency bands, Sybilla Pro analyzes the signal across multiple bands. Each of the eight filters can be individually tuned in terms of center frequency and gain, with a fixed bandwidth of 1kHz. You can choose to enable or disable each filter independently, which gives you complete control over the sidechain input that drives the compression stage. This means you can zero in on exactly where the sibilance lives in the vocal (or any other source) and exclude the rest from the detection process.

Sybilla Pro functions as a wideband de-esser, meaning it compresses the entire signal when sibilance is detected, rather than applying frequency-selective gain reduction. What makes this approach powerful is how the plugin handles the sidechain input: the sum of the active filters is used to detect sibilant energy. When the combined energy of these filters crosses the threshold, compression is triggered. This allows the plugin to track dynamic changes in sibilance across the frequency spectrum, ensuring that it doesn’t miss anything — even if the problem frequencies shift over time.

One of the standout features of Sybilla Pro is its relative threshold system. Traditional de-essers use a fixed threshold, which often fails in quieter passages, allowing sibilance to sneak through when the overall signal is too low to cross the threshold. Sybilla Pro works differently. Instead of comparing the filtered signal to a static level, it compares it to the unfiltered, full-range signal, and uses the difference as the key input for the compressor. This means de-essing remains consistent, even during soft vocal phrases, giving a much more transparent and natural-sounding result.

At the core of the plugin is the filter bank, where you can fine-tune each filter by setting its frequency and gain. Each band remains fixed in bandwidth for consistency and clarity, and if you need to dive deeper into the processing, you can use the “key listen” feature to monitor the output of each filter individually, or the sum of the entire filter bank. This is an incredibly useful tool for identifying problem areas and optimizing filter placement.

Beyond the detection and filtering system, Sybilla Pro also gives you two distinct compression modes: VCA and OPTO. Each has its own characteristics, offering flexibility depending on the material you’re working with. The VCA mode is more aggressive, with a hard knee and fast, punchy response, ideal for precise and quick control. The OPTO mode, on the other hand, is more relaxed, with a soft knee and smoother transitions, making it perfect for more musical or subtle de-essing. In both modes, you can manually adjust the attack and release times to match your preferences and the needs of your mix.

What truly sets Sybilla Pro apart is how it combines advanced processing with intuitive control. You’re not just setting a threshold and hoping for the best — you’re actively sculpting the detection system to match the unique character of your audio. Whether you’re working on dialogue, vocals, podcasts, or even instrumental tracks, Sybilla Pro gives you a precise tool for taming harshness without sacrificing the integrity of the original signal.

By offering a multi-band, tunable detection system, a relative threshold, and the option to choose between two compression styles, Sybilla Pro bridges the gap between surgical control and musical response. It’s perfect for modern mixing environments where clarity, intelligibility, and transparency are more important than ever.