Testing Audio Performance of Hearables
Testing hearables, or smart headphones, is challenging. They have various interfaces ranging from hardwired to wireless and often contain signal processing on both the record and playback side. This means that their characteristics change according to ‘real world’ conditions such as their physical environment and background noises. Furthermore, their multifunctional nature means that there are many aspects of the device that may need to be tested, ranging from voice recognition to music playback or even operation as a telephone headset or hearing aid. In this AES paper, we discuss how to implement basic acoustic tests as well as the more complex real-world tests, techniques, standards, and equipment that are necessary.
Authors: Steve Temme, Listen, Inc.
Presented at AES Headphone Conference 2019, San Francisco, CA.
Full Paper
Poster Presentation
Abstract & introduction for “Testing Audio Performance of Hearables”
Abstract for “Testing Hearables”
Smart headphones or “hearables” are designed not only to playback music but to enhance communications in the presence of background noise and in some cases, even compensate for hearing loss. They may also provide voice recognition, medical monitoring, fitness tracking, real-time translation and even augmented reality (AR). They contain complex signal processing and their characteristics change according to their smartphone application and ‘real world’ conditions of their actual environment, including background noises and playback levels. This paper
focuses on how to measure their audio performance under the many various real-world conditions they are used in.
Introduction for “Testing Hearables”
Hearables are notoriously challenging to test. They have various interfaces ranging from hardwired to wireless (e.g. Bluetooth) and may contain much signal processing, both on the record side (e.g. beamforming, background noise filtering, voice activity detection, and on the playback side (e.g. loudness, compression, equalization, and active noise cancellation). This means that their characteristics change according to ‘real world’ conditions such as their physical environment and background noises. Some even have wake word detection, e.g. ‘Hey Siri’. Furthermore, their multifunctional nature means that there are many aspects of the device that may need to be tested, ranging from voice recognition to music playback or even operation as a telephone headset or hearing aid. Due to their complex non-linear use cases, these devices often need to be tested at different levels and in different environmental conditions, for example with background noise, different signals etc. Although, there are currently no standards for testing smart devices such as hearables, we can borrow principles and test configurations from many other audio devices and use existing standards such as; IEC for headphones [1], IEEE for headsets [2], ETSI for background noise [3], TIA/ITU for telephone test [4] and ANSI for hearing aids standards [5].
Flexibility of the test system and experience with testing a wide range of acoustic devices is critical to enable a device to be completely characterized. This paper discusses how to implement basic acoustic tests and some of the more complex real-world tests along with the techniques and standards that may be used. Test system requirements for measuring voice
enabled hearables will also be discussed.
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