Posts

Automotive Max. SPL Measurements

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In this short article, Steve Temme introduces the efforts of the Audio Engineering Society (AES) technical committee working on automotive audio to standardize the way essential attributes of complex automotive
audio systems are measured across the industry. He explains why Max SPL measurements are important, defines this measurement, and describes the standardized measurement procedure suggested by the committee. Test configuration and physical setup is discussed, and example results presented.

Full Article

Enhanced Perceptual Rub & Buzz Measurement for Testing Automotive Loudspeakers

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Loudspeaker Rub & Buzz faults are a problem for automotive manufacturers as they sound harsh and immediately give the perception of poor quality. There are two places such faults can occur – during speaker manufacturing and installation of the speaker in the car. A buzzing loudspeaker in a car is disappointing to a customer and is costly to replace. It is also challenging for a service center to determine exactly where the buzzing is coming from and whether it is caused by a faulty loudspeaker or bad installation. Perceptual distortion measurements are often considered the holy grail of end-of-line testing because rejecting speakers with only audible faults increases yield. Although such measurements have been around since 2011, production line adoption has been slow because until now, sensitivity to background noise has made limit-setting challenging. In this paper, a new algorithm is introduced that uses advanced technology to reduce the impact of background noise on the measurement and offer more repeatable results. This facilitates limit setting on the production line and makes it a truly viable production line metric for increasing yield. This same metric may also be used for end-of-line automotive quality control tests. Results from various algorithms will be shown, and their correlation to subjective and other non-perceptual distortion metrics explained.

Authors: Steve Temme, Listen, Inc.
Presented at 2022 AES Automotive Conference, Dearborn, MI

Full Paper

Automotive Audio Testing Seminar

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July 21st, 2022. 9.00am and 2.00pm Eastern US time (6.00am and 11.00am West Coast time)
July 27th, 10.00am China time

In this practical online seminar, Steve Temme will demonstrate in-car measurement of frequency response, Max SPL, and Buzz, Squeak and Rattle using a Bluetooth connection. He will discuss considerations such as physical setup, infotainment system controls and the measurement parameters. Steve and his colleagues will then discuss connectivity for automotive testing, explaining and demonstrating the various connectivity options including USB drive, Bluetooth and A2B bus. Finally, we’ll take a look at some of the other audio measurements that you can make using SoundCheck, for example active noise cancellation and voice assistance readiness. 

在这个实用的网络研讨会中，Steve Temme 将演示如何使用蓝牙连接进行车内测量，以测量频率响应、最大 SPL 以及异常音。 他将讨论物理设置、信息娱乐系统控制和测量参数等考虑因素。 然后，Steve和他的同事将讨论汽车测试的连接性，解释和演示各种连接选项，包括 USB 驱动器、蓝牙和A2B 总线。 最后，我们将看看其他您可以透过SoundCheck进行的音频测量，例如主动降噪以及voice assistance readiness测量。

Register for 9.00am Event Register for 2.00pm Event Register for China Event

Automotive Max SPL

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The sequence measures the Max Sound Pressure Level (SPL) of a car infotainment system in the vehicle’s interior

The sequence uses a 6 microphone array mounted at either the driver or passenger locations. A 30 second pink noise stimulus having an RMS level of -12 dBFS is played through the infotainment system and captured by SoundCheck’s Multi-channel Real Time Analyzer (RTA). The Multi-channel RTA produces 6 RTA curves which are then power averaged to produce a Max SPL Spectrum. The spectrum is then power summed to produce a single value for Max SPL.

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Seminar at Sound Hub

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Today, Steve Temme presented on how to measure voice activated devices such as smart speakers, hearables and automotive audio, as well as how to use SoundCheck for basic audio measurements at Sound Hub Denmark, the world’s leading audio innovation hub and co-working space.In the morning, he presented the basics of SoundCheck, and taught attendees (many of whom had access to the SoundCheck system at Sound Hub) how to build a test sequence in SoundCheck. recommendations for the equipment used. After lunch, he explained in depth how to test voice activated devices such as automotive infotainment systems, hearables, and smart speakers. These devices are complex to test as they have numerous wired and wireless connections and often contain signal processing, both on the record and the playback side. In this session, he outlined the test configurations, tools and techniques that enable accurate measurement of the audio performance of such devices under the many various real-world conditions in which they are used.

The Challenges of Testing Voice-Controlled Audio Systems

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Smart devices that are voice-controlled such as smart speakers, hearables, and 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 the playback side. This means that their characteristics change according to ‘real world’ conditions of the environment that they are used in, such as background noise, playback levels, and room acoustics. 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, operation as a hands-free telephone, and in the case of hearables, hearing assistance. Due to their complex non-linear use cases, these devices often need to be tested at different levels and different environmental conditions. This paper focuses on tools and techniques to accurately measure the audio performance of such devices under the many various real-world conditions in which they are used.

 

语音控制的智能设备（例如智能扬声器、听觉设备和车辆信息娱乐系统）非常难以测试。它们具有从有线到无线的多样连接方式，并且在接收端和重放端使用了诸多信号处理技术。这意味着它们的特性会随着使用环境的“现实世界”条件（例如背景噪声、播放级别和室内声学条件）的不同而变化。 此外，它们的多功能特性意味着可能需要测试该设备的许多方面，包括语音识别、音乐播放、作为免提电话或听觉设备或助听器使用时的性能。由于其复杂的非线性使用情况，这些设备通常需要在不同级别和不同环境条件下进行测试。本文重点介绍在各种实际条件下准确测量此类设备的音频性能的工具和技术。

Author: Steve Temme, Listen, Inc.
Presented at ISEAT 2019, Shenzhen, China.

Full Paper – English Version
Full Paper – Chinese Version

AES Convention– New York – October 16-19, 2019

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Although Listen won’t be exhibiting, president Steve Temme will be at the event and will be participating in two product development sessions detailed below.

 

Product Development: PD09 – Does Automotive Audio Need a Systems Approach?

Thursday, October 17, 1:30 pm — 3:00 pm (1E09)

Chair: Roger Shively, JJR Acoustics, LLC

Panelists: John Busenitz, Bose Corporation, Pietro Massini, Ask Industries S.p.A, Greg Sikora, Harman International, Steve Temme, Listen, Inc.

Some component specifications do not translate to good system performance. A good example is resonance frequency. This often does not correspond well to performance characteristics in the automotive environment. Some potential improvements would be low-frequency SPL, or a parameter combination such as Fs/Qts or EBP (Fs/Qes). The system performance goals should drive the transducer component specification. Hence, this workshop will host leading industry experts in automotive audio and test/measurement solutions to discuss pros and cons of component vs. system specifications.

 

Product Development: PD10 – Diagnostics for Production Vehicle Audio Systems

Thursday, October 17, 3:15 pm — 4:30 pm (1E09)

Presenters: Jonathan Gerbet, Klippel GmbH, Steven Hutt, Equity Sound Investments, Steve Temme, Listen, Inc.

Audio systems in production vehicles are known to exhibit vehicle to vehicle performance variance [1]. The root causes of variance can include loudspeaker driver manufacturing tolerance, mounting issues such as missing or misaligned gaskets, or wrong loudspeaker drivers mounted in the system. A diagnostics method to compare actual production vehicle audio systems is defined along with a method for correction and calibration of production vehicle audio systems. The diagnostics procedure may be implemented at production end-of-line, at vehicle distribution center or at a dealer service center in the field after delivery to a customer.

Full AES Schedule

Testing Voice-Controlled & Smartphone Integrated Infotainment Systems

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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