HoRNet CompExp

Nice compression and expansion

HoRNet CompExp is a unique compressor/expander plugin that brings a fresh perspective to dynamic processing by emulating a special kind of compander chip originally developed for use in telephone lines. While its primary purpose was noise reduction in long-distance analog communication, this vintage circuit offers surprisingly musical behavior when applied to audio production. With HoRNet CompExp, this rare dynamic shaping is now available as a powerful creative and technical tool for music producers, mixing engineers, and sound designers.

Inspired by Classic Compander Technology

At the heart of HoRNet CompExp is the emulation of a compander chip widely used in electronics to reduce noise in low-fidelity systems like telecommunications, cassette players, and consumer audio devices. A compander (short for compressor/expander) works by compressing the dynamic range of audio before transmission and expanding it again upon reception. This process lowers the noise floor introduced by analog systems and ensures clearer signal reproduction.

We took this vintage design and implemented it with high accuracy, staying true to its original fixed-threshold behavior and unique gain curve. However, we also discovered that using either the compressor or expander stage independently yields musical and unexpected results, giving CompExp its distinctive sound.

Fixed Threshold Compression and Expansion

Unlike typical compressors or expanders where you can manually adjust the threshold, HoRNet CompExp uses a fixed threshold internally set at -18dBFS. This design mimics the behavior of the original hardware chip and ensures that all dynamic shaping revolves around a consistent reference level.

The core parameter in CompExp is the “Amount” knob, which determines how aggressively the processor acts on the signal:

• When the Amount is set to a value greater than 1, and the mode is compressor, the signal is compressed above the threshold and boosted below it. This behavior results in dynamic leveling and a controlled, smooth output.

• When the mode is switched to expander, the gain changes in the opposite direction. The plugin boosts the signal above the threshold and reduces it below, effectively widening the dynamic range and emphasizing the signal’s transients and quiet details.

This simple yet flexible design makes HoRNet CompExp highly effective for both technical applications (like reducing noise or evening out levels) and creative uses, such as shaping transients, emphasizing dynamics, or even crafting vintage-style pumping effects.

Versatile Dynamic Response

By using a non-traditional fixed-threshold model, CompExp creates a more natural response curve that doesn’t rely on the typical attack/release envelope shaping. Instead, the plugin reacts to the signal’s energy in a way that’s more instantaneous and level-dependent, resulting in cleaner processing and fewer artifacts, especially when working with transient-rich or delicate audio material.

This unique behavior is especially effective on:

• Drum overheads for subtle transient enhancement

• Bass tracks to smooth out inconsistencies without crushing dynamics

• Vocals to lift quiet phrases while controlling louder parts

• Synths and pads to add gentle motion and dynamic complexity

Additionally, this approach allows you to explore new sonic territory, making HoRNet CompExp not just a problem-solving tool, but also a creative sound design processor.

Consistent Output via Internal Gain Compensation

One of the challenges in working with compression and expansion—especially using non-standard curves—is maintaining a consistent output level. To address this, HoRNet CompExp includes internal gain compensation that automatically adjusts the output to remain near a target level of -18dB RMS.

This ensures that no matter how aggressively you push the Amount knob or whether you use the plugin in compression or expansion mode, the average output level remains balanced. You won’t need to constantly adjust your gain staging as you experiment with different settings.

This feature is especially useful in complex mixing chains or mastering sessions, where consistent level is essential for making meaningful comparisons between processed and unprocessed audio.

Legacy Inside: From HoRNet HDD1 to a Standalone Processor

The internal model used in HoRNet CompExp was originally implemented as part of the HoRNet HDD1, where it served as a noise-reduction circuit in the feedback path of the delay processor. The unique properties of the compander chip allowed the delay tail to stay clean and intelligible, even after multiple feedback loops.

Due to its success in that context—and its unexpectedly musical response—we decided to build a dedicated plugin around this technology. The result is CompExp, a tool that brings this unusual yet effective form of dynamic processing to any track or session.

Minimal Interface, Maximum Results

As with all HoRNet plugins, CompExp offers a clean and efficient user interface that prioritizes usability. All the key parameters are presented in a compact layout, making it easy to set up and tweak without menu-diving or unnecessary complexity. The minimal control scheme—focused on the Amount setting and mode selection—ensures fast results and encourages experimentation.

Despite its simplicity, the sonic results are deep and varied. With just a few adjustments, you can shift from subtle leveling to aggressive transient enhancement, or from noise-reduction to dynamic expansion, making HoRNet CompExp a versatile addition to any producer’s or engineer’s toolkit.

Conclusion: Vintage-Inspired Dynamics, Reimagined for Modern Workflows

HoRNet CompExp combines the charm of vintage analog dynamics with the flexibility and precision of modern digital processing. Its unique fixed-threshold design, dual compressor/expander functionality, and internal gain compensation make it an exceptional tool for both technical and creative applications. Whether you’re looking to tame dynamics, enhance subtle details, or simply try something new, HoRNet CompExp delivers reliable, musical results in a lightweight and intuitive format.

By taking inspiration from decades-old technology and adapting it for today’s needs, CompExp provides producers and engineers with a fresh, creative approach to dynamic control—an approach that’s fast, effective, and sonically inspiring.