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Testing Voice-Controlled & Smartphone Integrated Infotainment Systems

A tutorial and accompanying paper that was presented at the AES Automotive Conference, Sept 11-13, 2019, Neuburg an der Donau, Germany.

Voice-controlled and smartphone integrated vehicle infotainment systems are notoriously complex to test. They have numerous connections from wired to wireless and contain much signal processing, both on the record and on the playback side. This means that their characteristics change according to ‘real world’ conditions of the vehicle’s environment, including cabin acoustics and background noises from road, wind and motors. 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 and operation as a hands-free telephone. Due to their complex non-linear use cases, these devices often need to be tested at different levels and different environmental conditions.

This tutorial offers practical hands-on advice on how to test such devices, including test configurations, what to measure, the challenges of making open-loop measurements, and how to select a test system.

Download presentation (slides)

Download accompanying paper

AES International Conference on Automotive Audio – Munich – September 11-13, 2019

Listen is a gold sponsor and exhibitor at the AES International Conference on Automotive Audio in Munich, Germany on September 11-13.

Listen founder and president, Steve Temme, will be presenting a tutorial on ‘Testing Voice-Controlled and Smartphone Integrated Infotainment Systems’ at 2pm on Sept 11th. In this tutorial he will discuss the challenges of implementing audio tests in cars when the signal path is often via a smartphone and/or the car’s own voice-controlled system, and demonstrate how modern test systems can use techniques such as frequency shift and resampling to enable accurate measurement of car audio characteristics ranging from simple frequency and distortion measurements to voice control and communications in the presence of background noise.

On display at the the booth will be various options for testing automotive audio including the SoundCheck test system, Listen’s own audio test hardware, and 3rd party hardware such as 6 microphone arrays and head and torso simulators. On the booth, Listen will also be demonstrating how SoundCheck fully integrates with, and controls, the Mentor A2B interface to enabled rapid automated testing of systems and components that use the A2B bus.

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SoundCheck/Mentor A2B for Automotive Audio

mentor_a2bWe are excited to announce that SoundCheck fully integrates with the Mentor A2B interface for testing automotive audio connected via the Analog Devices A2B digital bus. The Mentor Analyzer, which handles the transmission of signal in to and out of the bus, is viewed as an ASIO interface by SoundCheck, enabling SoundCheck to read/write to the device and therefore analyze any transducer connected to the A2B bus. A custom VI permits control of the Mentor A2B interface configuration via SoundCheck. This means that it can be controlled from within a SoundCheck sequence, for example loading configurations and starting/stopping ASIO streams. This makes it an ideal R&D or production line test solution for automotive audio, or for anyone testing transducers connected via A2B bus.

Watch a video demonstration of an automotive audio test using the Mentor A2B interface:

 

Please see our knowledgebase article for download links and installation instructions.

Contact your Listen sales engineer for more information.

Triggered Record Using WAV File and 6 Mic Array

This sequence allows you to measure a playback system without analog inputs using a 6 microphone array. Specifically, the sequence is designed to measure an in-car audio system. A stimulus WAV file is created in SoundCheck and transferred to the device under test (DUT) where it is played back and the response captured by SoundCheck using a triggered record function. The 6 recordings are batch analyzed to produce individual fundamental curves and the curves are post-processed to produce a single average curve from which an average sensitivity value is calculated.

Final display for Triggered Record Sequence

Final display for Triggered Record Sequence

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In-Vehicle Distortion Measurement

Authors: Zarina Bhimani, Steve F. Temme (Listen, Inc.), Patrick Dennis (Nissan Motor Co.).  Reprinted from the 2017 Loudspeaker Industry Sourcebook.

Steve Temme and Patrick Dennis discuss their research exploring test methods that will help determine audible distortion and enable manufacturers to test sound equipment after it is installed

Full Article

 

 

Evaluation of Audio Test Methods and Measurements for End-of-Line Automotive Loudspeaker Quality Control

In order to minimize costly warranty repairs, automotive manufacturers impose tight specifications and a “total quality” requirement on their part suppliers. At the same time, they also require low prices. This makes it important for automotive manufacturers to work with automotive loudspeaker suppliers to define reasonable specifications and tolerances, and to understand both how the loudspeaker manufacturers are testing and also how to implement their own measurements for incoming QC purposes.

Specifying and testing automotive loudspeakers can be tricky since loudspeakers are inherently nonlinear, time variant and affected by their working conditions & environment which can be change dramatically and rapidly in a vehicle. This paper examines the loudspeaker characteristics that can be measured, and discusses common pitfalls and how to avoid them on a loudspeaker production line. Several different audio test methods and measurements for end-of-the-line automotive speaker quality control are evaluated, and the most relevant ones identified. Speed, statistics, and full traceability are also discussed.

Authors: Steve Temme, Listen, Inc. and Viktor Dobos, Harman/Becker Automotive Systems Kft.
Presented at the 142nd AES Convention, Berlin, Germany

Full Paper

New Automotive Audio Testing Brochure

automotive_flyer_pictureA new 4 page brochure outlines Listen’s capabilities in automotive audio testing. SoundCheck offers simple, fast and accurate testing of vehicle audio quality, from individual speaker components to complete in-vehicle infotainment and telematics systems. With interfaces to connect via Bluetooth, Lightning, USB and with individual MEMs devices, as well as analog connections, SoundCheck can handle the complexity and demands of testing in today’s vehicles. The measurements that SoundCheck can make include:

  • Speaker/system response
  • Speaker/panel buzz, squeak and rattle
  • Bluetooth audio performance
  • Head unit and amplifier response & THD+N
  • Microphone/microphone array response
  • Active noise cancellation effectiveness
  • Spatial reproduction accuracy

Download brochure    download_pdf_icon