Jeroen Breebaart has released Isone Pro, a new Binaural Room Simulator plug-in - it enables you to enjoy a virtual listening room, using headphones. It costs €20 and is available for Windows as a VST effect plug-in.

The perfect listening room... Many have experienced the difficulty to realize a listening environment free of standing waves, undesirable reflections, the perfect reverb time, perfect loudspeaker placement with a flat frequency response and without any disturbance for others. With Isone Pro, a virtual listening room can now be experienced simply using a set of high-quality headphones. Allowing for full control over loudspeaker type, loudspeaker distance, room size, reverb time, the virtual listening room can be fully customized.

Flexibility
Isone Pro is quite flexible in its use. In its simplest mode, Isone Pro only simulates the inter-aural cross-talk that is inherent to loudspeaker listening. Additional attributes such as pinna reflections (or 'elevation cues'), inter-aural time differences (ITDs), room acoustics, and loudspeaker models can be added depending on the application at hand. Of course aspects such as soloing loudspeakers and mono compatibility checks are supported as well. It can even simulate the sound you will hear when stepping out of the listening room for a stroll towards the coffee machine.

Parametric individual HRTF technology
A virtual listening room is typically created by simulating the acoustical transfer from loudspeakers to both ears. These acoustical transfer properties are often referred to as Head Related Transfer Functions (HRTFs). Such HRTFs can be measured for each individual using specialized equipment. The measured transfer functions can subsequently be used as filters to simulate a virtual sound source over headphones (see this link for more background information).

Although the use of HRTFs has been shown to be very effective in numerous scientific publications, it also has well-documented shortcomings. For example, HRTFs vary from person to person; applying the wrong HRTFs results in significantly degraded sound source localization. It is therefore crucial to match HRTFs to each individual listener for a convincing effect.

Although many solutions exist for 3D binaural audio, JB says that Isone Pro is the first VST plug-in that allows for pseudo-personalized HRTFs. It has unique means to adjust the HRTFs for each individual listener, by compensating for differences in the anthropometric properties of the head and ears (pinnae). This provides an improved elevation, azimuth and distance perception over non-individualized approaches. The adjustments are based on recent advancements in binaural processing which are also incorporated in novel ISO/MPEG audio standards. During the ISO/MPEG standardization process, a large-scale double-blind listening test employing various approaches for binaural processing indicated that so-called parametric HRTFs provide the highest possible quality and the lowest CPU load. Such parametric HRTFs form the basis of this binaural room simulator plugin.

Room simulation
Simulation of the acoustic environment is essential for a compelling simulation of loudspeaker listening over headphones. Music or other audio content is almost never listened to in an anechoic environment, and those who have experienced audio playback in such anechoic rooms know that this results in a very unpleasant listening experience. Moreover, your audience will listen to the content you work on in the car or in the living room, or any other echoic environment and hence it is crucial that the audio producer or engineer can estimate the effect of a room on the content he or she is working on. It is not without a purpose that international standards for audio reproduction rooms dictate a certain minimum reverberation time. Nevertheless, the room simulation module in Isone Pro can be switched on or off if desired.

Applications:

• Prolonged headphone listening with reduced listening fatigue.
• Audio mixing and mastering over headphones (virtual reference monitoring).
• Generation of podcasts with binaural (3D) audio.

Features:

• Zero latency processing.
• Low CPU load.
• Sample rate support up to 384 kHz.
• Customizable HRTFs.
• Customizable listening room and distance.
• 'Listen next door' feature.
• Wide variety of included loudspeaker models:
  • Acoustic Energy AE2
  • Auratone 5C
  • Avi Pro9
  • KRK V8
  • PMC LB-1
  • Roland DS50A
  • Tannoy Reveal
  • Yamaha NS10M
  • Laptop speakers
  • Portable music player
  • Flat-panel TV