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New Transient Distortion Measurement Algorithm

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At Listen, we’re at the forefront of audio measurement research, and we’re always looking to improve on existing audio measurement techniques, even our own! Loose Particle detection has been a valuable production metric for analyzing transient distortion since we launched it in 2004. This new iteration uses our own original research to improve accuracy and reliability, show a clear correlation to audibility, and simplify limit setting. In addition to production line testing of speakers, headphones, drivers and other devices, it is also valuable for automotive Buzz, Squeak and rattle (BSR) measurements and measuring rattling components such as keys and buttons on a variety of devices. All is explained in the short video below.

Transient Distortion Detection Launch Video

Watch our launch video (broadcast date 05/25/2023) for the full details.

 

Ready to Measure your Transient Distortion?

If you have SoundCheck 21, you already have this new algorithm! Download our free complete end of line test sequence with enhanced Loose Particles to start using it right away.

If you don’t have SoundCheck 21, but have an older version, you can send us your recorded waveforms and we’ll analyze them for you and send you the results. Please contact sales@listeninc.com for a test sequence to record the waveforms.

No SoundCheck system at all? No problem! You can send us your speakers and we’ll test them for you. Or we may be able to arrange a system loan. Contact your sales engineer at sales@listeninc.com for more information.

Prefer to Read About It?

We know not everyone has 15 mins free to watch a video, although its hard to beat the benefits of a proper demonstration. So here’s a brief summary of the information about this new algorithm that is presented in the video:

What it does

The new algorithm measures transient distortion caused by loose particles that may become trapped in a device during manufacture and create an unpleasant sound when they vibrate in the finished product. This is measured in the time domain rather than the frequency domain as these artifacts appear randomly over time, and not periodically in the same way that harmonic distortion artifacts are presented. This algorithm has a couple of unique features:

1) It measures transient distortion separately from harmonic distortion which gives deeper insight into the failure mode and accelerates troubleshooting, particularly on the production line.

2) It’s easy to correlate with audibility as the algorithm removes the stimulus waveform to allow the user to listen to just the distortion artifacts. As well as enabling the user to truly understand how measured results correlate to listening, this also facilitates limit setting.

3) It’s reliable even in the presence of transient background noise since it relies on a cumulative event count rather than a single event triggering a fail. Limit setting is simple as it is not frequency dependent

 

Applications

  • Production line driver test
  • Production line finished product test (rattling buttons, keys, grills, and other components)
  • Buzz, Squeak and Rattle (BSR) / Impulsive distortion measurements in cars

 

How it works

Like Listen’s original 2004 transient distortion detection algorithm, enhanced Loose Particles relies on a time domain analysis of the waveform. However, rather than simply filtering and counting transients, it removed the stimulus, performs a time domain analysis of the remaining transients, then applies a unique Prominence calculation to evaluate each transient in the context of the surrounding waveform. A threshold is applied, and the number of transient events above that threshold are counted. The event count indicates whether a device has a transient distortion problem. Transient events caused by speaker manufacturing issues tend to repeat many times as particles bounce around in side the speaker, or components vibrate. In contrast, background noise events occur infrequently during the duration of the measurement. The threshold is set based on audibility, and the Loose Particle count limit can be set according to the environment to fine-tune the algorithm for the specific operating conditions.

 

Graphic demonstrating how the Transient Distortion algorithm (Loose Particles) works

4 Stages of the enhanced Loose Particles algorithm for transient distortion measurement: Response waveform, Loose Particle waveform, Prominence and enhanced Loose Particles.

 

 

For additional background, comparison to other methods, such as Crest Factor Analysis, and live demonstrations, please check out the video above.

 

Learn More

Huge Discounts on SoundCheck 21 Upgrades!

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For a limited time we are offering deep discounts on a system upgrade to enable you to get up to date with the latest version of SoundCheck. The upgrade offer is a simple flat rate: $4,175 for owners of SoundCheck 15 or 16, $3,402 for owners of version 17, $2,646 for owners of versions 18 and 19, and $1,465 for owners of version 20. All the modules on your present system will be included. Promotional pricing is valid till June 30th, 2023.

When you upgrade to the latest version of SoundCheck, the license is perpetual – in other words, you keep all the new features you have acquired for ever (or until you decide to upgrade to an even newer version).  Please ask us if you have any questions about upgrade licensing!

SoundCheck® 21 offers new features for both R&D and Production, as well as many usability upgrades including:

  • Enhanced Loose Particle Detection: A new enhanced Loose Particle detection algorithm for measurement of transient distortion is more accurate and offers improved correlation to subjective listening. In addition to identifying distortion caused by foreign material in the voice coil gap of a speaker, it is also valuable for detecting rattling buttons on smart devices and Bluetooth speakers, and identifying buzz, squeak and rattle in automotive audio applications.
  • Multichannel Spectrum Analyzer: A new multi-channel FFT analyzer replaces SoundCheck’s original single channel spectrum analyzer. This high resolution constant bandwidth linear filter analyzer enables any number of live FFT spectra to be simultaneously viewed in real time on the same graph.
  • Metadata for Simplified Data Collection and Recall: SoundCheck’s new Metadata feature simplifies data collection and documentation. Curves, values, results and waveforms can now be saved to a single TDMS file, along with all test parameters acquired during the sequence run such as test conditions, test sequence used, operator, serial number, microphone position, data entered via a message step and more.
  • Sequence Protection: Sequence protection guards your intellectual property and adds an additional level of assurance that your tests are run as-intended by your production facility or contract manufacturer. Any test sequence can now be locked and password protected before distribution. This prevents sequence steps and limits from editing and sequence steps cannot even be viewed, protecting the intellectual property in your sequences.
  • AudioConnect 2 Support: SoundCheck 21 supports AudioConnect 2TM, Listen’s new portable, compact and high resolution (up to 192 kHz) dual-channel audio interface. AudioConnect 2 is designed for measurements anywhere from the production line to out in the field.

Upgrade from Version

Upgrade List Price

Promotional Upgrade Price

Discount

15

$9,450

$4,175

56%

16

$7,875

$4,175

47%

17

$6,300

$3,402

46%

18

$4,725

$2,646

44%

19

$3,150

$2,646

16%

20

$1,575

$1,465

7%

If you are using a version prior to version 15, please contact your sales engineer for discounted price information.

PLEASE NOTE:

  • Versions of SoundCheck prior to 16 are no longer supported. We highly recommend that you take advantage of this limited time offer to upgrade your systems to the latest version. Please contact your sales engineer to discuss additional multi-system upgrade discounts.
  • If you have multiple systems with different purchase dates, we are happy to work with you to get them all upgraded to the latest version and onto the same annual support contract cycle.
  • You can also reduce your future upgrade costs by purchasing an annual support contract for an additional $998. With this, you will receive SoundCheck 22 when it is released at no extra charge, as well as priority support service.
  • Discounted upgrade prices are only available to registered owner of software, for their exclusive use.

Please note that these prices are applicable to the US only. Users outside the US should contact Listen or their local representative for pricing information.

Please email your purchase order to sales@listeninc.com. You can also contact us on this email address if you would like to pay by credit card, have any questions, or need additional paperwork to support your order.

Please also see the detailed information on new features.

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SoundCheck Online Basic Training, May 2023

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Registration is now open for our Online SoundCheck Basic Training class from May 9th-18th.

The course will again consist of 6 x 2-hour sessions over a 2 week time period, and will cover all the same content as our standard in-person basic training course. Each session is led by a live trainer and will include instruction, demos, quizzes, breakout sessions and discussion. Hands-on exercises will be provided to be completed between sessions and reviewed in subsequent classes.

We are restricting attendance to 30 attendees to better facilitate breakout sessions, so sign up early to secure your spot. Registration closes on May 1st, and a 10% early booking discount will apply to all registrations received by April 17th.

Dates: May 9th, 10th, 11th, 16th, 17th, 18th

Time: 6 x 2hr sessions from 11.00am-1.00pm Eastern US Time (8.00am-10.00am Western US Time)

Attendees must attend all 6 sessions to complete the course.

Cost: $295 ($195 for support contract holders). Additional discounts for multiple people from the same company signing up together (2-3 people: 10%; 4 people: 15%; 5+ people: 25%). Additional 5% early bird discount when signing up prior to April 17th.

Instructors: Mark Latshaw and Pranav Swaroop

Course Outline

Session 1: Hardware & Calibration – Configuring audio interfaces and external equipment; certified audio interfaces; Calibration of different DUT types (telephones, speakers, etc.)

Session 2: Memory list, Data management, Virtual Instruments (Spectrum Analyzer, RTA, Multi-meter, Signal Generator, Oscilloscope), Sequence Editor Basics

Session 3: Sequence Writing Part 1 – Introduction to the sequence editor; stimulus; acquisition; basic analysis

Session 4: Sequence Writing Part 2 – Limits; Displays; Autosave; Recall; Printing

Session 5: Sequence Writing Part 3 – Messages & sequence logic; Post Processing; Statistics

Session 6: Sequence Writing Part 4 – Sequence Writing Examples

 

Group discounts are available for multiple attendees from the same company:

2-3 attendees: 10% discount

4 attendees: 15% discount

5+ attendees: 25% discount

 

Early bird discount: 10% until April 17th.

Register Now

 

Note about late signups: As training starts imminently, we do not have time to ship demo keys. This means that in order to participate fully, you must have a relatively up-to-date (version 20 or 21) hardware key available to use. If you do not, you can still follow along with the training in demo mode, but you will be unable to complete some of the hands-on exercises.

SoundCheck 21 Brings Enhanced Loose Particle Detection, Multichannel FFT, Metadata, Sequence Protection and more

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Listen is excited to release SoundCheck 21, the latest version of its flagship audio test software. This version includes a new enhanced Loose Particles algorithm for transient distortion measurements in a wide range of devices. It also offers increased measurement capability with the new multichannel FFT analyzer. Other enhancements such as the ability to save metadata, sequence protection and AudioConnect 2 control round out the increased functionality of this year’s update.

The new enhanced Loose Particle detection algorithm offers more accurate measurements of transient distortion and improved correlation to subjective listening. It also makes it easier to  distinguish defects from background noise. The new algorithm uses the same time-envelope analysis technique as in Listen’s original 2005 Loose Particle algorithm, the first method developed for detecting random transient production line defects. However, this new version adds a prominence metric to better distinguish  the loose particle defects from other artifacts, and removes the stimulus from the response so only the defects are heard.  This makes it easy to set limits in line with subjective tests. In addition to identifying distortion caused by foreign material in the voice coil gap of a speaker, it is also valuable for detecting rattling components such as buttons on smart devices and bluetooth speakers, and identifying buzz, squeak and rattle such as loose wires or fasteners in automotive audio applications.

SoundCheck’s focus on multichannel analysis continues with a new multi-channel high resolution FFT analyzer to replace the original single channel spectrum analyzer. This enables any number of live FFT spectra to be simultaneously viewed in real time on the same graph, allowing direct comparisons and saving screen real estate over the previous methods of using a separate analyzer for each channel. Channel subtraction, maximum, minimum and power average can be calculated and displayed in real time, and the analyzer offers many options including standard and custom windows and various weighting options. Live FFT curves can easily be dragged and dropped into any graph for easy comparison to limits and reference curves. FFT analyses can be viewed simultaneously with RTA analyses, either side by side or superimposed on one another. This enables both high resolution spectra and constant percentage bandwidth resolution (eg. 1/12th Octave) measurements to be viewed at the same time.

The new Metadata feature simplifies data collection and documentation. Curves, values, results and waveforms can now be saved to a single TDMS file, along with all test parameters acquired during the sequence run such as test conditions, test sequence used, operator, serial number, microphone position, data entered via a message step and more. Both system fields (e.g. sequence name, operator, SoundCheck serial number) and user-defined fields can be stored.  This data can be viewed or recalled in SoundCheck, as well as by applications such as Microsoft Excel and Matlab. The TDMS format used for Metadata saves it in a binary format, minimizing read and write times when a sequence is running. This feature has many uses in both R&D and production applications.

SoundCheck 21 also includes new features designed to ensure test integrity and protect intellectual property when sharing test sequences with 3rd party manufacturers. Any test sequence can be locked and password-protected. Once locked, it can be run but sequence steps and limits cannot be edited without the password. Furthermore, the sequence steps cannot even be viewed, guarding the intellectual property in your sequences. Sequences can also be configured to only run on a particular SoundCheck system, or block of systems. This further protects against unauthorized use and helps ensure the end-to-end integrity of your tests, guaranteeing that your products are tested exactly as intended.

Finally, SoundCheck 21 supports AudioConnect 2TM, Listen’s new compact and high resolution (up to 192 kHz sampling rate) two-channel audio interface. With the option to power it via a laptop USB-C port, this compact, portable, and easy to use audio interface is designed for measurements anywhere from the production line to out in the field, and is particularly suitable for headphone testing. Set-up and configuration is extremely simple and fast with full plug-and-play functionality and TEDS support for automatic identification, configuration and calibration of microphones and accelerometers. AudioConnect 2 is exclusively configured via the SoundCheck software – there are no front panel controls. This provides an added level of test integrity by ensuring that settings cannot be inadvertently adjusted outside of your test configuration.

More information

 

SoundCheck Basic & Advanced Training, Feb/Mar 2023 – Denmark

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We’re excited to be back training in-person later this month in Copenhagen – a great location easily accessible from much of Europe.

We’re offering both our 2 day basic training and our 1 day advanced training consecutively. Attend either, or if you want to seriously power up your SoundCheck knowledge, come to both for 3 action-packed days!

Dates: Basic Training Feb 27th-28th. Advanced Training Mar 1st

Location : IDA Copenhagen, Kalvebod Brygge 31-33, 1780 København V (just 15 minutes from the airport).

Presenters: Mark Latshaw and Steve Temme

This training is being held in partnership with our Scandinavia distributor, Vibrakustik. You can find full information about the training including course outlines and cost here: SoundCheck Training 2023.

If you would like to register for the training, or have any questions please contact Vibrakustik directly.

AES75 (M-Noise) Measurement of Max SPL for Loudspeakers

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The new AES75-2022 standard for Measuring Loudspeaker Maximum Linear Sound Levels Using Noise is a complex test process which uses the M-Noise test signal developed by Meyer Sound to measure the maximum linear sound levels of a loudspeaker system or driver. This test signal was specifically developed to emulate the dynamic characteristics of music.

Implementing the standard manually relies on an operator’s subjective judgment of real time spectrum analyzer data, and is labor intensive since it requires multiple iterations of a measurement. Our free SoundCheck test sequence fully automates the entire measurement, using calculated results to drive subsequent steps in the procedure. This removes subjectivity, increasing reliability, and saving time. This short video introduces the test sequence with a short demonstration.

Video Demo

Try it Yourself

Would you like to try this yourself? If you already have SoundCheck, you can download the AES75 (M-Noise) test sequence. Please note that you will need the waveform filter (part # 2032) and transfer function (part # 2021) modules installed on your SoundCheck system. You can download the AES75 Standard from the Audio Engineering Society website.

 

 

Video Script:

Make Max SPL Measurements to the AES 75 Standard using M-Noise

Our pre-written test sequence automates measurement to the new AES 75 standard for Maximum SPL, removing subjectivity, increasing reliability, and saving time.

This standard details a method for measuring maximum linear sound levels of a loudspeaker system or driver using M-Noise, a test signal specifically developed to emulate the dynamic characteristics of music. Clearly defined limits for linear frequency response and coherence determine the Max SPL level and remove any measurement ambiguity.

Implementing the standard manually relies on an operator’s subjective judgment of real time spectrum analyzer data. It also requires multiple iterations of a measurement, therefore is labor intensive.

Our test sequence is fully automated. We use the same test signal and calculations outlined in the standard, but automated analysis steps objectively calculate the measurements and drive the next steps in the procedure.

Let’s take a look.

Here, you can see we are using the freely available M-Noise test signal introduced by Meyer Sound. This stimulus features a relatively constant peak level as a function of frequency, but a diminishing RMS level with increasing frequency.

First, we use a test signal approximately 20dB below our expected Max SPL to obtain a provisional linear frequency response, linearity, coherence and signal to noise ratio. We then increase the test level by 3dB, and compare the results to the initial value. The results must be within +/- 1dB, have a coherence of at least 97% and a signal to noise ratio 15dB or higher so that we know we are operating in the speaker’s linear region and our signal to noise ratio is sufficient for accurate measurements.

Next we automatically increase the test level by 3dB and compare it to the initial results, normalized to the current test level. Multiple measurement iterations take place until one of the ‘stop’ conditions is reached. These conditions are either:

  • the live measurement differs from the linear frequency response by at least 2 dB over at least two octaves
  • the live measurement differs from the linear frequency response by at least 3 dB anywhere, or
  • the Coherence Reduction Target is met –  this means the signal to noise ratio is 10dB or less and/or the coherence is 91% or less.

When one of these limits is reached, the sequence then reduces the test level to the last level that passed and repeats the measurements in 1dB increments to find the precise Level at which the response deviates from the base level.

Once this level is established, the device enters a burn-in process, where the M Noise stimulus is played through the DUT for five minutes and fifty-three seconds and again compared to the initial result. This long duration measurement is also used to generate peak, rms and A weighted RMS sound levels. If the response curve remains consistent, this curve is the Max SPL curve according to the standard. If it is not within the acceptable limits, the device is cooled down and the tests repeated with a longer stimulus duration.

All the operator needs to do is enter any stimulus limits based on the operating range of the DUT into the sequence before starting, then return when the test is complete.

As well as saving time, SoundCheck mathematically calculates the data in analysis steps within the sequence, which avoids the subjectivity of relying on operator interpretation of real-time spectrum analyzer outputs. This increases repeatability and confidence in the results. This sequence is available free of charge on our website. Check it out!

ISEAT 2022,October 29-30 2022, Shenzhen, China.

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Listen President, Steve Temme, will be presenting a paper entitled ‘Enhanced perceptual rub & buzz measurement for loudspeaker production test’.  Due to Covid-19 regulations, this paper will be presented by video.

ISEAT Web Site

 

SoundCheck Online Basic Training, October 2022

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Registration is now open for our Online SoundCheck Basic Training class from October 4th-13th.

The course will again consist of 6 x 2-hour sessions over a 2 week time period, and will cover all the same content as our standard in-person basic training course. Each session is led by a live trainer and will include instruction, demos, quizzes, breakout sessions and discussion. Hands-on exercises will be provided to be completed between sessions and reviewed in subsequent classes

We are restricting attendance to 30 attendees to better facilitate breakout sessions, so sign up early to secure your spot. Registration closes on September 26th, and a 10% early booking discount will apply to all registrations received by September 15th.

Dates: October 4th, 5th, 6th, 11th, 12th 13th.

Time: 6 x 2hr sessions from 11.00am-1.00pm Eastern US Time (8.00am-10.00am Western US Time)

Attendees must attend all 6 sessions to complete the course.

Cost: $295 ($195 for support contract holders). Additional discounts for multiple people from the same company signing up together (2-3 people: 10%; 4 people: 15%; 5+ people: 25%). Additional 5% early bird discount when signing up prior to September 15th.

Instructors: Mark Latshaw and Pranav Swaroop

 

Course Outline

Session 1: Hardware & Calibration – configuring audio interfaces and external equipment; certified audio interfaces; Calibration of different DUT types (telephones, speakers, etc.)

Session 2: Memory list, Data management, Virtual Instruments (Spectrum Analyzer, RTA, Multi-meter, Signal Generator, Oscilloscope), Sequence Editor Basics

Session 3: Sequence Writing Part 1 – introduction to the sequence wizard; stimulus; acquisition; basic analysis; limits

Session 4: Sequence Writing Part 2 – Displays; Autosave; Recall; Printing

Session 5: Sequence Writing Part 3 – Messages & sequence logic; external control; sequence & step parameters

Session 6: Advanced Sequence Development – Post Processing; Statistics

 

Group discounts are available for multiple attendees from the same company:

2-3 attendees: 10% discount

4 attendees: 15% discount

5+ attendees: 25% discount

 

Early bird discount: 10% until Sept 15.

Register Now

 

We are also running Advanced Training, November 15-17th. Learn more.

SoundCheck Online Advanced Training, November 2022

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Registration is now open for our Online SoundCheck Advanced Training class from November 15th-17th. Advanced training is designed for users familiar with the content of the basic class who need to make more complex measurements and want to take their SoundCheck use to the next level.

The course consists of 3 x 2-hour sessions (one per day for 3 consecutive days), and will cover three separate advanced training topics. Each session is led by a live trainer and will include instruction, demos and discussion.

Sign up early to secure your spot!  Registration closes on November 7th, and a 5% early booking discount will apply to all registrations received by Sept 16th.

Dates: November 15th, 16th, 17th.

Time: 3 x 2hr sessions from 11.00am-1.00pm Eastern US Time (8.00am-10.00am Western US Time)

Cost: $175 ($115 for support contract holders). Additional discounts for multiple people from the same company signing up together (2-3 people: 10%; 4 people: 15%; 5+ people: 25%). Additional 5% early bird discount when signing up prior to March 18th.

Instructors: Steve Temme and Mark Latshaw

 

Course Outline

November 15th: Advanced Sequence Development
This session continues where basic sequence development left off, covering topics such as advanced stimulus and analysis options, conditional branching and looping, advanced post-processing algorithms and more.

November 16th: Advanced Measurement Techniques
This session will cover two popular and rapidly growing measurement techniques, open loop testing and simulated free field measurement. Open loop testing (including Bluetooth) will discuss in detail the considerations when making open loop measurements, and examine in detail the advanced triggering options available in SoundCheck. The Splice method of obtaining simulated free field measurements was developed by Steve Temme almost 20 years ago and is currently surging in popularity due to its ability to offer reliable measurements in an office or home environment.

November 17th: Advanced Distortion Measurements
Steve Temme takes a deeper dive into the mechanics of distortion and the various distortion measurement techniques available in SoundCheck. Part educational, part SoundCheck instruction, he covers causes and analysis of THD, higher order harmonic distortion, loose particle detection and perceptual distortion methods.

 

Group discounts are available for multiple attendees from the same company:

2-3 attendees: 10% discount

4 attendees: 15% discount

5+ attendees: 25% discount

 

Early bird discount: 5% until Sept 15.

 

Register Now

We are also running Basic Training Oct 4-13th. Learn more.

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