FOR IMMEDIATE RELEASE

JVCKENWOOD “EXOFIELD” Headphone Technology
Replicates the Acoustic Space of a Room

Localization sound field processing technology allows headphone users to hear music
as if it’s coming from speakers in the front of the room.

The technology will be demonstrated at CES 2018.

LAS VEGAS, January 5, 2018 – JVCKENWOOD will be at CES 2018 demonstrating its EXOFIELD technology that enables headphones to provide the wide sound field and precise stereo imaging until now only possible when listening to speakers positioned across the room.

With conventional headphones, sound comes from inside the listener’s head, or sometimes from the sides. JVCKENWOOD’s EXOFIELD localization sound field processing technology moves sound out of the listener’s head to replicate the experience of enjoying music in a listening room, with the sound emanating from speakers in the front of the room with a clear stereo image. The effect is accomplished by measuring the listener’s personal characteristics – such as the shape of the ears and face – and the acoustic properties of a specific listening room and loudspeakers. The result is that the listener, while using headphones, hears music the way it would sound when listening in that specific room to the speakers that were measured.

JVCKENWOOD calls the technology “EXOFIELD” for “EXO” as in “external”, and “FIELD” in reference to the sound field, to convey the technology’s ability to move the sound field out of the listener’s head.

Purpose of Development

With the popularity of digital audio players and smartphones, more and more people are listening to music through headphones. Headphones are excellent at reproducing a delicate sound quality and nuances. However, when using conventional headphones, sound transmitted to users through their right and left ears is localized inside users’ heads. Thus, conventional headphones have a weakness in reproducing the spatial sound field and localization of sound images that users experience when listening to music through speakers.

To deal with such shortcomings, JVCKENWOOD developed EXOFIELD, a unique out-of-head localization sound field processing technology that when listening to headphones reproduces the sound field and localized sound images experienced when listening to music on speakers in a listening room. It achieves this by leveraging JVCKENWOOD’s accumulated technologies in sound reproduction. The new technology uses sound field processing based on measurement of various acoustic characteristics, including personal characteristics, and excels at reproducing the depth and placement of sound images, notably of those localized to the center position, which can not be achieved well with conventional out-of-head localization technology. As a result, the new technology creates a realistic sound field when listening with headphones, as if the user is listening to music on speakers. In addition, users do not feel like music is playing in their ears. Therefore, EXOFIELD brings a natural sound listening experience to users who might experience uncomfortable sound pressure with conventional headphones. In addition, EXOFIELD supports the reproduction of multi-channel audio sources, enabling three-dimensional sound field reproduction in headphones in a home theater or virtual reality environment, etc.

Key Features

1. The technology measures various acoustic characteristics of individuals to enable optimal sound field processing for “out-of-head” localization sound fields.

Conventional “out-of-head” localization headphone technology performs arithmetic processing by using a standard head-related transfer function. As a result, headphones are not adjusted to fit individual users who have different shape ears and faces, and so cannot deliver optimal performance for each user. JVCKENWOOD’s EXOFIELD makes it possible to measure and analyze the personal characteristics of individual users, such as the shapes of their ears and face, as well as the acoustic characteristics of audio speakers, headphones and listening rooms to perform audio signal processing that is optimally customized to individual users. The technology creates the optimal sound field for each user, unlike the conventional out-of-head localization sound field.

Graphic illustration of sound localization

2. Measurement using the industry’s first* in-ear audio microphone system allows creation of a natural sound field in both open-back and closed-back headphones.



JVCKENWOOD developed an ultra compact in-ear audio microphone system using a MEMS microphone to measure users’ individual characteristics. The ultra compact microphone system put in the ear canal makes it possible to accurately measure head and ear shapes as well as sound field characteristics of users’ ear canals. By enabling users to easily fix the position of the microphone system they are wearing to the ideal measurement location regardless of the individual difference in the shape of ears, stable and highly accurate measurement is achieved. The result is a listening experience with a natural sound field in open-back headphones as well as closed-back headphones, for which conventional out-of-head localization was considered relatively ineffective in reproducing natural sound.

In-ear audio microphone system

3. Newly developed algorithm to generate personal characteristics can measure and automatically generate optimal acoustic characteristics in a short amount of time

The newly developed algorithm to generate personal characteristics can measure and automatically generate the optimal acoustic characteristics for each user in a short amount of time. The use of this algorithm minimizes the variation of the effect of the out-of-head localization sound field due to a difference in the measurement environment, such as listening room conditions or incorrect wearing position of headphones. Accordingly, EXOFIELD can adapt to a wide range of measurement and use conditions by performing optimization processing of a transfer function calculated from measurement results.


Conceptual diagram of EXOFIELD’s sound field processing.

* The first commercially available measurement system for out-of-head localization when listening with headphones (based on data as of March 14, 2017).

      a. Clarification of center sound image localization

EXOFIELD analyzes direct waves and reflection waves coming from speakers and corrects the cancelling out of sound due to the positional relationship between speakers and listeners and the effects of sound reflection in a room. This makes the center sound image clearer, which is a problem with conventional out-of-head localization technology. In addition, sound image localization at the proper center position is achieved by fine-tuning the phase characteristics of each channel in inverse filter generation to cancel the sound field reproduced with headphones in out-of-head localization sound field generation.

 

b. Minimizing the variance of characteristics caused by incorrect headphone postion.

EXOFIELD optimizes the change in frequency characteristics and a peak dip caused by an incorrect wearing position of headphones during generation of the inverse filter that cancels the sound field reproduced via headphones. This stabilizes the variation in the localization effect caused by an incorrect wearing position of headphones.

 

c. Completing measurement and personal characteristics generation quickly.

The technology uses the pulse method, a quick measuring process, to measure impulse response and so makes it possible to quickly complete measuring and generating the personal characteristics. In an environment where measurement of a low-pass filter is subject to instability due to the effects of the surrounding environment and room conditions, EXOFIELD can generate stable low-pass characteristics in a short time by combining pre-measured room acoustic characteristics with personal characteristics. 

4. Measured data and EXOFIELD processing can be uploaded to smartphone apps, etc. 

By installing EXOFIELD application software with personal properties data on mobile devices using an app, users can enjoy the benefits of the technology any place. 

5. Supports a wide range of applications such as high resolution and multi-channel audio sources. 

EXOFIELD supports high-resolution audio sources and can process all audio signals into high-resolution audio sources. EXOFIELD can also reproduce both stereo sound and multi-channel audio sources, enabling three-dimensional sound field reproduction via headphones in a home theater or virtual reality environment, etc. EXOFIELD brings an unprecedented natural listening experience to users by offering clear localization, which is not reproduced adequately by a conventional three-dimensional sound field. 

About JVCKENWOOD USA Corporation

JVCKENWOOD USA Corporation is a wholly-owned subsidiary of JVCKENWOOD Corporation and is a leading developer of imaging, home and car entertainment and navigation products for the consumer market, two-way radio communications systems for public safety, private industry and amateur users, and video equipment for the broadcast and professional markets. For detailed information, call JVCKENWOOD USA at 1-800-950-5005 or visit us at http://us.jvckenwood.com, www.kenwoodusa.com and www.jvc.com.

EXOFIELD is a trademark or registered trademark of JVCKENWOOD Corporation. All other company names and product names are trademarks or registered trademarks of their respective holders.

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