Helmut Keller Audio has announced the release of a new audio plugin designed to improve spatial perception when listening through headphones. The plugin focuses on recreating aspects of loudspeaker listening that are typically absent in headphone playback.
Listening on headphones differs from loudspeaker monitoring primarily due to the lack of natural acoustic crosstalk between the listener’s ears. In a loudspeaker setup, each ear receives sound from both speakers, influenced by head and ear geometry. The newly released plugin addresses this by introducing a crossfeed process intended to approximate this acoustic behavior in a controlled and repeatable way.
At the core of the plugin is an approximation of an interaural transfer function corresponding to an azimuth angle of 30 degrees and an elevation angle of 0 degrees. This transfer function is implemented using a combination of a second-order minimum phase filter and a delay line. According to the developer, this processing is applied within the crossfeed path of the plugin to recreate interaural interactions that occur naturally in loudspeaker listening.
In addition to the crossfeed processing, the plugin includes a dedicated equalizer designed to manage the balance between mono compatibility and stereo integrity. The equalizer allows users to move smoothly between full mono compatibility and minimal spectral alteration when working with typical stereophonic signals. This approach is intended to support consistent listening conditions while preserving the original balance of the source material.
The plugin has been released in JSFX format and runs natively within the Reaper digital audio workstation. JSFX is Reaper’s built-in scripting-based plugin format, allowing direct integration without additional wrappers or external plugin formats.
For users working in other digital audio workstations, compatibility can be achieved through the YSFX bridge plugin developed by Joep Vanlier. YSFX enables JSFX plugins to run in a wide range of plugin hosts by providing standard plugin formats across platforms. With this approach, the Helmut Keller Audio plugin can be used beyond Reaper-based workflows.
Key technical and compatibility details include:
- JSFX plugin format with native support in Reaper
- Crossfeed processing based on an approximated interaural transfer function
- Minimum phase filtering combined with time delay for spatial simulation
YSFX itself is provided as a VST3, AU, and CLAP plugin, supporting Windows, macOS, and Linux systems. This allows the plugin to be integrated into most modern audio production environments without changes to the original JSFX code.
The plugin is intended for headphone listening scenarios where a more speaker-like spatial impression is desired, particularly during monitoring, mixing, or general listening tasks that benefit from controlled stereo perception.
The Helmut Keller Audio plugin is available free of charge from the developer’s website. YSFX is also available for free as a VST3, AU, or CLAP plugin for Windows, macOS, and Linux.
Click here to find out more about the Crossfeed plugin X Feed by Helmut Keller Audio.
Set a dev alert for Helmut Keller Audio.
Do you have an opinion?
Let us know what you think about this news in the comments section below.
