Tag Archive for: production test

100 Things #100: Production Line Audio Measurement With SoundCheck

Everyone knows SoundCheck is a versatile and flexible R&D audio test system. But did you know it’s also fast and cost-effective for production line audio measurement, and offers unrivaled integration with larger factory test environments?

End of line testing is nothing new to us. We started the global trend from human listeners and expensive hardware analyzers to software-based test systems back in 1995. Many of the measurements we introduced in the 1990s are still used today. Besides introducing newer and better measurement methods like perceptual algorithms, we’re driving the integration of audio testing within a larger factory test environment. Let’s take a look at some of the things that make SoundCheck great for end-of-line tests.

Production Line Audio Measurement with SoundCheck

 

Learn More About SoundCheck’s Production Line Features

Seminar Recording: External Control of SoundCheck. Detailed information about controlling SoundCheck as part of a large factory automation system.

Video: 100 Things #85: Integrate SoundCheck with your Database.

Video: 100 Things #11: External Control Using TCP/IP

Transitioning Audio Tests from R&D to the Production Line. An article by Steve Temme, reprinted from the March 2023 edition of AudioXpress.

 

Video Script: Production Line Audio Measurement

Everyone knows SoundCheck is a versatile and flexible R&D audio test system. But did you know it’s also fast and cost-effective for production line testing, and offers unrivaled integration with larger factory test environments?

End of line testing is nothing new to us. We started the global trend from human listeners and expensive hardware analyzers to software-based test systems back in 1995. Many of the measurements we introduced in the 1990s are still used today. Besides introducing newer and better measurement methods like perceptual algorithms, we’re driving the integration of audio testing within a larger factory test environment. Let’s take a look at some of the things that make SoundCheck great for end-of-line tests.

Most importantly, SoundCheck’s fast and reliable. Every test algorithm we’ve designed has speed and noise immunity at the forefront, from our unique stepped sine wave stimulus, Stweep, and Harmonictrak analysis back in 1995 to the second generation of perceptual distortion measurements in more recent years. And all our production line measurements, use the same stimulus to ensure fast throughput with simultaneous measurement of all parameters.

Soundcheck is hardware-agnostic, and compatible with many audio interfaces from our own custom designed all-in-one hardware to off the shelf soundcards. It even supports audio over IP with Dante. It works with any brand of amplifiers, microphones, couplers and test jigs. It’s also easy to control footswitches, PLCs, barcode readers and other production line equipment through a custom step in a test sequence. This gives you total flexibility, whether you are re-using existing hardware or building a system from scratch.

Both hardware and software are modular, so you can get the production functionality you need, without paying for anything that you don’t. Although a production system is significantly cheaper than an R&D SoundCheck system, it’s still fully compatible – you can create tests on an R&D system and send them to your production systems, or bring results from your production system back into an R&D system for detailed analysis.

However, it’s the seamless integration with custom factory test systems that really differentiates SoundCheck.

Full TCP/IP control lets SoundCheck communicate on any operating system, via any TCP/IP-supportive language including python, c-sharp and Labview. TCP/IP commands can trigger a test, pass the output back to an external program, or even pull in externally stored sequence parameters such as limits and stimuli. This allows the same test sequence to be used for many different products, reducing the sequence maintenance burden.

SoundCheck is just as flexible for saving data. Standard data formats include text, csv, Excel, TDMS, Matlab and SoundCheck’s open source binary file format. There’s also a plugin for WATS Test Data Management software. You can use an autosave step in your sequence to write curves, values, results, or waveforms directly to an SQL database each time a sequence is run, and industry standard tools can then be harnessed to run analytics over large data sets. If these options aren’t enough, all the data, curves, and other  items saved in SoundCheck’s memory list, can always be accessed directly via TCP/IP, so you can write your own customized program to collect exactly the SoundCheck data you need.

SoundCheck’s built-in security features provide peace of mind if you share your tests with manufacturing partners. Sequence protection locks and hides all the information in a sequence so that it can be run, but not viewed or altered. So you have confidence that your products are tested exactly how you intended. No-one can adjust the limits to achieve higher yield, and it removes the risk of  your tests being modified and re-purposed for use on other product lines. To add further security and measurement confidence, a sequence can even be configured to only run on a particular SoundCheck system, or block of system hardware keys.

These features let you bring the power of SoundCheck into pretty much any large automated test platform, no matter what software and operating system it is running on. Talk to your sales engineer to learn more.

 

 

A New Method for Transient Distortion Detection

Transient distortion, or ‘loose particle’ measurement, is an important loudspeaker production line quality control metric that identifies and facilitates troubleshooting of manufacturing issues.

This paper introduces a new enhanced loose particle measurement technique that discriminates more accurately and reliably than current methods. This new method introduces ‘prominence’ after envelope detection, a new metric for audio measurements, that effectively isolates transient distortion in the presence of periodic distortion. This technique also offers the unique ability to listen to the isolated transient distortion waveform which makes it easier to set limits based on audibility and has widespread applications.

Authors: Steve Temme, Rahul Shakya and Jayant Datta, Listen, Inc.
Presented at 155th AES Conference (October 2023) New York, NY

Full Paper

 

Paper Introduction

Transient distortion, or ‘loose particle’ measurement, is a valuable quality control metric because it identifies non-periodic distortion, for example, rattling parts, separately from periodic distortion such as rubbing or buzzing parts. This facilitates troubleshooting of manufacturing issues. This paper introduces a new transient distortion measurement technique that is more accurate and reliable than current methods. In addition to improved performance, this new algorithm also aids understanding of the correlation between measurement results and audibility, since it is possible to isolate and listen to just the transient distortion artifacts. Although this analysis method was developed for measuring loose particles in loudspeaker drivers, it is also valuable for measuring rattling parts such as buttons, fasteners, and loose wires on various audio devices, and measuring impulsive distortion or Buzz, Squeak and Rattle (BSR) in automotive audio applications [1].

What is Transient Distortion? Why does it matter?

Transient distortion is caused by random clicking, popping, and other noises in the time domain. In a speaker or headphone driver, this might be caused by foreign particles such as glue or magnet fragments trapped in the gap behind the diaphragm or dust cap. In a device such as a smart speaker, transient distortion might come from a loose volume control button on the device that rattles when sound is played. In an automotive application, it could be characterized as buzz, squeak and rattle from loose wires, screws or fasteners in a car door that the loudspeaker is mounted in. In all cases, the sound is undesirable, so devices that exhibit such faults should be identified and rejected.

In the recorded time waveform, transient distortion faults appear as impulsive noises added on the stimulus wave. These impulses are not related to the frequency of the stimulus, but rather to the vibration caused by the displacement amplitude of the diaphragm. The transient distortion is more frequent and significant when the speaker is driven near or below its resonant frequency, where the displacement of the diaphragm is the greatest.

Although the sound – a random clicking, buzzing or popping noise – can sometimes sound similar to higher order harmonic distortion (Rub & Buzz), such defects are not clearly reflected in the frequency spectrum of the waveform. Figure 1 shows a waveform with transient distortion, and the corresponding frequency spectrum. The vertical black line represents the stimulus frequency and the orange broadband noise spectrum indicates the transient distortion. Transient distortion is best identified at the time the transients occur, unlike Rub & Buzz distortion which is best identified by the frequency at which it occurs [3].

The entire paper also covers:

Prior Measurement Methods

The new algorithm – comparison and results

Conclusions

Download paper

In addition to this paper, please also check out the Enhanced Loose Particles Webpage and our detailed video explanation of how this algorithm works.

Transitioning Audio Tests from R&D to the Production Line

Steve Temme discusses the transition from R&D to production testing in this March 2023 issue of AudioXpress. Production line audio testing poses many challenges such as noisy environments, harsh operating conditions, high throughput, relative limits, and more. In this article, Steve Temme shares his observations and outlines the main considerations to ensure a successful operation.

Full Article

 

Introduction to Production Line Audio Testing Article

Your product design is finalized, your prototypes are close to perfect, and your audio product is ready to move to production. But how do you ensure that the product hitting the retail shelves sounds exactly as you intended?
Your production line is probably thousands of miles away, with time zone and language complications. Pandemic-related restrictions make it hard to visit to configure, supervise, and train factory personnel. Furthermore, production is often outsourced to a contract manufacturer, adding another layer of complexity to both culture and information transfer.
Every production facility has one priority: to build products that meet the specifications with the greatest efficiency and highest yield possible for optimum profitability. Think about what that means for end-of-line tests. Their goal is to have as many units pass as possible. Tests must be fast to avoid slowing down the production line, and the test environment is generally noisy, often with variable temperature and humidity. The quest for high yields and manufacturing efficiency, along with challenging operating conditions and sometimes poor training, can result in unreliable measurements. When this happens, the only loser is you and your brand’s reputation.
I’ll never forget being told about a production line operator who increased pass-rate by opening the test box during measurements so that the factory background noise would mask the high-order harmonics to fool the perceptual Rub & Buzz algorithm. This might improve his yield, but it’s not so good when these products ship to customers! While this is one of the more outrageous violations of end-of-line test protocol, I have also seen many other questionable measurement practices over the years. In this article, I’ll try to de-mystify production tests and look at some simple measures that you can take to ensure a smooth transition.

Full Article

100 Things #47: Using Panel Lock for Reliable Hardware Configurations

Buttons, knobs, and switches on interfaces are great for device flexibility, but not so great for reliability. Inadvertent adjustments can easily happen, causing inaccurate measurements and downtime for re-calibration. Listen’s interfaces feature a panel lock, a software controlled feature which prevents any physical buttons from changing an interface’s state. This is great for busy factory environments, where it would be easy to accidentally change a setting and render your measurements worthless.

Using Panel Lock To Ensure Test Integrity

Learn More About SoundCheck’s Advanced Features

Read more about SoundCheck’s advantages for production applications.

More information is also available in the  SoundCheck Manual.

 

Video Script: Using Panel Lock for Reliable Hardware Configurations

From its beginnings back in 1995, SoundCheck was designed to integrate with off-the-shelf sound cards and audio interfaces for data acquisition. Since 2009, we’ve also offered our own line of audio test hardware including audio interfaces, microphone power supplies, power amplifiers and more… all geared specifically for audio test and measurement.

There are many advantages of using Listen hardware with SoundCheck. It is true plug and play, making setup and calibration much faster and easier, and the tight integration enables full software control and the inclusion of features such as input gain autoranging.

One often overlooked feature is the front panel lock. When you’re using 3rd party hardware, there are usually many buttons on the front, which, if accidentally adjusted, can mess up your calibration and therefore your measurement accuracy. We’ve actually eliminated front panel controls from many of our interfaces, but for those that do still have knobs, such as AmpConnnct ISC and SoundConnect 2, you can lock the front panel via the software to prevent any unintended changes that could compromise your measurements.

When Panel lock is enabled, operators cannot inadvertently make changes to the hardware from the front panel, giving you confidence in your hardware settings and your measurements. This is particularly valuable in factory environments.

 

 

 

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