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Introducing Enhanced Loose Particles (eLP)

Watch our launch seminar for Listen’s latest algorithm, enhanced Loose Particles (eLP). This new algorithm significantly improves production line transient distortion measurement. It offers high accuracy, easy correlation to human perception, and identifies transient distortion artifacts separately from harmonic distortion for easy troubleshooting. It’s also ideal for identifying rattling buttons in audio devices, and automotive Buzz, Squeak and Rattle (BSR) measurements. This new algorithm is based on original research, and uses techniques not previously used for distortion measurement. Check out this demonstration and detailed explanation of how this algorithm works by Listen president Steve Temme.

Introducing Enhanced Loose Particles

Read on to learn more

For all things Enhanced Loose Particles including listening examples, published articles, and details of the eLP methodology, check out our Enhanced Loose Particles page.

Listen’s new enhanced Loose Particle algorithm offers accurate transient distortion measurements, even in the presence of background noise. This algorithm is highly accurate, as well as easy to configure and set limits. Results are easily correlated to audibility by listening to the loose particles in the recorded waveform.

This algorithm uses the same time envelope analysis as our pioneering (2004) Loose Particles algorithm, but rather than filtering and counting pulses, additional analysis is applied to measure the prominence, or impulsiveness, of the detected artifacts. The algorithm calculates the prominence of each loose particle event in the waveform by comparing the magnitude of a peak relative to the surrounding minimums, which reflects the impulsiveness of the artifact more accurately than the absolute magnitude of the peaks.  A user-defined prominence threshold determines the level at which the peak will be counted, and a user-defined count of events over the time window determines the pass/fail threshold.

Objective results obtained by this method are easily correlated to subjective analysis as you can listen to the recorded waveform with the fundamental removed, hearing only the loose particles. This enables the prominence threshold to easily be set based on defect audibility.

This analysis method is inherently reliable in a factory environment as external background noise events typically only occur once or twice during a measurement, whereas many loose particle transients will occur during the same timeframe. The event count is user-determined, and is set according to the background noise in the measurement environment. Prominence threshold and loose particle count are the only parameters that the user needs to define, so limit setting is simple, well correlated to audibility, and can be configured to give reliable results even when background noise is present.

The New POLQA Module in SoundCheck

The optional POLQA (Perceptual Objective Listening Quality Analysis) module brings Opticom’s POLQA 3 algorithm, as specified in the ITU-T P.863 standard, right into SoundCheck (Version 20 and later). POLQA Analysis is a fast and cost-effective alternative to a panel of human listeners for perceptual measurements of speech degradation in communications applications ranging from telephones to smart devices. The quality of the speech signal is evaluated by comparing the degraded signal to the corresponding reference signal to determine the Mean Opinion Score (MOS). This end-to-end analysis may be implemented using either acoustic, digital, or electrical signals, and with either narrowband (300-3400Hz) or full band (10-20000Hz) signal analysis.

The New POLQA Module in SoundCheck

Ready to try for yourself?

If you are ready to add the new POLQA module to your SoundCheck system, contact your local sales engineer or sales@listeninc.com with any questions.

Learn more about POLQA and SoundCheck

Read on about all POLQA algorithm functionality, licensing, applications, and more.


Video Script: Using POLQA Analysis in SoundCheck

Opticom’s POLQA version 3 algorithm as specified in the ITU-T P.863 standard is integrated directly into SoundCheck. It operates just like any other post-processing step. Within soundcheck you can configure the reference and response waveforms, set test parameters and define outputs through the familiar soundcheck interface. The POLQA algorithm is called from within soundcheck and returns results as graphs and tables like any other analysis. It can of course be used within sequences to accelerate and simplify test procedures and can also be used to process imported data using batch file processing.

POLQA is a valuable addition for anyone testing speech quality and communications devices. Some common applications of this test might include assessing the impact of a noise reduction algorithm on an audio communication system, evaluating the perceived audio degradation in a Bluetooth connection due to packet loss, analyzing distortions introduced in the audio path, or quantifying the impact of various speech codecs on perceived speech quality. Let’s look at a few possible  POLQA setups.

Here is an example of a setup we can use for characterizing the perceived audio degradation at a Bluetooth connection due to packet loss. The mouth simulator plays back a reference WAV file that is recorded through the Bluetooth microphone, the recorded degraded responses are compared to the original reference WAV file, and the mean opinion score or MOS is returned.

Here’s an example of another possible  POLQA test. In this setup, an end-to-end call can be established, for example a call can be made to a conference phone which is the device under test, and the signal on the receiving end is recorded and analyzed for speech quality. Let’s look at a simple  POLQA SoundCheck sequence.

This sequence is similar to the conference phone setup I just displayed. The sequence uses the batch processing capability introduced into SoundCheck 20 to access pairs of wav files for  POLQA analysis. These wav files are temporarily loaded into the memory list and passed through the  POLQA post-processing step for analysis. This loop recalls and analyzes four sets of wav files, and reports the POLQA mean opinion score on a scale of one to five one being poor, five being best, and a score of around four considered very good.

The advantage of batch processing is that I can conceivably test hundreds or thousands of pairs of wav files without loading all the files into a sequence at once, efficiently managing the sequence size, memory, and performance. Let’s look at the  POLQA post processing step. The step compares the recall to reference and response files; the drop list allows you to select the measurement type – acoustic, digital or voltage. This drop-down shows the operating modes options including full band, narrow band, and super wide band including the latest version 3 algorithm. It also supports Opticom version 2.4 if you need to correlate results with a lab that uses the Legacy 2.4 algorithm. In addition to the MOS, we can choose additional outputs including ASR, attenuation, delay, MOS per frame, pitch, R-factor and SNR.

Since the sequence is using recall wav files you won’t hear the speech files when I run the sequence but I’ll play back the reference WAV file through my signal generator so you can hear what’s being analyzed. I’ll run the sequence and note the highlighted steps in the sequence editor particularly through the loop which will run four times before the final display steps. There are two tabs in my display step. As you watch the sequence run this display set shows the active iteration of the four wav files being analyzed. The top display shows the reference WAV file, and the bottom displays the reference wav file along with the response file superimposed. In the second display step we see the mean opinion scores, or MOS, of the four wav files and additional outputs below. These are displayed in tables and we can see the MOS scores are 3.4, 3.98, 3.4 and 3.98. As you can see, SoundCheck’s integration of  POLQA is fast and easy and an essential addition for characterizing speech quality.

Communications Testing Seminar

Communications tests are not just for telephones! In this demo-packed seminar with communications industry expert, John Bareham, we demonstrate how to evaluate devices such as smart speakers, headphones and wearables as well as all types of phones using industry standard procedures. We discuss equipment, standards, and demonstrate sections of the TIA920B and TIA5050 standards, as well as Doubletalk measurements and POLQA analysis, all within SoundCheck.


Communications testing demonstrations include:

  • TIA-920B
  • TIA-5050
  • Doubletalk

Presenters: Steve Temme, John Bareham, Les Quindipan
Duration: 52 mins

Communications Testing Measurement Resources

This seminar was originally broadcast on Dec 14th 2022. The recording below does not include the live Q&A at the end for attendee confidentiality reasons. However, several links to additional resources were provided during the Q&A session, and these are provided below.

  1. More about the TIA-920 Test sequence for SoundCheck This for-purchase sequence measures communications devices to TIA-920-B
  2. More about the TIA-5050 Test sequence for SoundCheck This for-purchase sequence measures communications devices to TIA-5050
  3. More about SoundCheck’s implementation of the POLQA Algorithm.

More about how to Measure Communications Devices

Check out our main page on Communications Testing, which includes links to test sequences, relevant products and more for testing telephones and other communications devices.

TIA – the Telecommunications Industry Association. Listen, Inc. works closely with this group to ensure that our measurement capabilities align with the measurements recommended by the AES.

SoundCheck 20 New Features

SoundCheck 20 introduces our state-of-the-art perceptual distortion algorithm for end-of-line testing – Enhanced Perceptual Rub & Buzz. It also includes a host of new features for multichannel and communications testing, increasing its capabilities for audio measurement of smart speakers, infotainment systems, headphones and hearables, and other voice-activated and multichannel devices.

SoundCheck 20 New Features

Read on to learn more

For a full list of all SoundCheck features, including version 20, check out SoundCheck: What’s New?

Listen’s new enhanced Perceptual Rub & Buzz algorithm is a reliable and repeatable method of detecting audible Rub & Buzz faults on the production line. This offers manufactures the option to increase yield by rejecting only those devices with audible distortion defects. Based on the sound psychoacoustic principles used in Listen’s industry-standard 2011 Perceptual Rub & Buzz algorithm, the new refinements improve listener correlation and demonstrate significantly better noise rejection to offer unrivaled repeatability. The multichannel Real Time Analyzer displays multiple channels simultaneously, and offers real time calculation and display of channel addition, subtraction, maximum, minimum and power average. Applications for this new feature include real-time observation of active noise cancellation, automotive industry standard 6-microphone array infotainment measurements, validating headphone seal on a test head prior to measurement by comparing left and right earphone response, and more. Paired with the AmpConnect 621 multichannel audio interface, it offers unmatched functionality for multichannel measurements on a wide array of devices, especially those featuring dynamic signal processing. RTA curves are now seamlessly integrated with SoundCheck’s standard graphs.

A complete overhaul of the signal generator brings additional functionality and simplified operation, particularly when using wav files. In addition to standard audio stimuli (sine, white noise, pink noise) with user-selected sampling rates and resolution, it can play any wav file, any memory list file, and any complex waveform created by the stimulus editor.
The optional POLQA (Perceptual Objective Listening Quality Analysis) module brings POLQA analysis right into SoundCheck, for perceptual measurements of speech degradation in communications applications ranging from telephones to smart devices. Version 20 extends SoundCheck’s batch processing power with the ability to automatically load and process external data. This is useful in any application where it is desirable to automate the testing of a large number of external data files via a sequence, for example wav files of speech recordings. New stimulus steps and post-processing capabilities support communications testing needs, for example, measurement of Doubletalk and other speech transmission parameters. These include a silence stimulus step, and RMS level versus time and histogram post-processing steps.

Introducing Enhanced Perceptual Rub & Buzz (ePRB)

The new Enhanced Perceptual Rub & Buzz (ePRB) algorithm increases production line yield by rejecting only those speakers with audible Rub & Buzz defects. It offers excellent correlation with human perception, unmatched repeatability and reliability and is fast, adding no addition time to end of line tests. Watch the launch video to learn more about this ground-breaking perceptual distortion algorithm.

Introducing Enhanced Perceptual Rub & Buzz

Read on to learn more

For all things Enhanced Perceptual Rub & Buzz including listening examples, published articles, and a sequence to try ePRB for yourself, check out our Enhanced Perceptual Rub & Buzz page.

Not all distortion is audible. Perceptual Rub & Buzz measurements identify only those devices with audible Rub & Buzz defects, rather than all Rub & Buzz defects. Basing end-of-line pass/fail decisions on this metric increases yield while maintaining customer satisfaction.

Listen’s new enhanced Perceptual Rub & Buzz algorithm is the first to perform better than the human ear. Its proprietary noise reduction technology and advanced perceptual algorithms make its performance in a noisy factory environment comparable to the performance of a human ear under normal listening conditions. In other words, it is the only perceptual Rub & Buzz metric that accurately correlates real-world end-of-line results with listener perception.

Furthermore, it is highly repeatable, simple to configure and set limits, and can be simultaneously implemented with other end-of-line tests with no increase in overall test time.

Production Testing Seminar

In this short seminar, Les Quindipan explores the use of SoundCheck for end-of-line electroacoustic production testing. He discusses typical test configurations and the type of measurements that can be made, how to set pass/fail limits and how to optimize tests for high throughput.

He also explains how SoundCheck is easily scaled for high volume electroacoustic testing, with such features as external control via another program and auto-saving data to databases, and how SoundCheck’s capabilities are easily expanded through the use of custom steps to control all types of devices and test fixtures.

This seminar will interest anyone considering a production line implementation of SoundCheck, or curious as to how to transition R&D measurements to fast and effective end-of-line test.

Production Testing demonstrations with SoundCheck include:

  • How to scale for high volume electroacoustic production testing, saving time and money
  • Typical audio measurements used in production testing
  • Production test setups
  • Optimizing test times and accuracy
  • Setting pass and fail limits in a test sequence
  • Auto-saving data
  • Custom Step Applications
  • Controlling SoundCheck externally from another program

Presenters: Les Quindipan
Duration: 18 Mins

More about Electroacoustic Production Testing with SoundCheck

A read on about at using SoundCheck for Production, as well as the transition of testing in a production environment from SoundCheck in the R&D Lab.

Take a closer look at the hardware used in this seminar, the AmpConnect 621.

Resources for Production Testing with SoundCheck

Learn more about the  WATS test data management system referenced in the video.

The New RT60 Module in SoundCheck

This short demonstration video showcases the new RT60 Room Acoustics module in SoundCheck, accurately characterizing measurement environments quickly using multiple microphones simultaneously.

The New RT60 Module in SoundCheck

Read on to learn more

Get the RT60 test sequence featured in this video.

The new RT60 module enables measurement of the reverberation time (signal decay time) and clarity (ratio of early reverberations to late reverberations) of any room or space. This is often necessary for product designers to fully characterize test rooms, for example, for characterizing rooms for voice recognition testing in various environments. Since many such engineers are already using SoundCheck for their tests, it makes sense to include this additional functionality within the same package. This also provides the user the assurance that their room acoustics measurements are performed with calibrated signal paths. SoundCheck offers extremely fast measurements using a continuous sine sweep with the Log TSR algorithm to obtain the impulse response. The reverberation decay curve is calculated from the backwards integrated impulse response. Aside from its speed, this method offers other significant advantages over the traditional direct method – it requires just one measurement at each location, and minimizes the effect of noise and distortion on the measurement. A free test sequence for characterizing the room is available.

The New AmpConnect 621 MultiChannel High Resolution Audio Interface

In this short video, Les Quindipan introduces the new AmpConnect 621 multichannel high resolution audio interface, explaining all its features and demonstrating how quick and easy it is to configure. AmpConnect 621 is a high resolution multichannel audio interface with 6 inputs, 2 line outputs, 1 amplifier output (plus everything else you need for audio testing!)

The New AmpConnect 621

Read on to learn more

For more details and technical specifications, check out the AmpConnect 621 product page.

AmpConnect 621 simplifies your multichannel audio test with 6 inputs, 2 line outputs and one amplifier output, along with microphone power, full TEDS support, impedance measurement and digital I/O in a single USB-connected unit. With sample rates up to 192kHz, it is ideal for the measurement of high resolution audio devices. AmpConnect 621 features 6 channels of audio test in a single unit, high accuracy impedance measurement independent of input channels, plug-and-play setup with error-free operation, front panel visual level indicators, and ground loop immunity, all in a rugged and rack-mountable for demanding production environments.

SoundCheck 19 New Features Video

In this short video, sales engineer Les Quindipan gives a brief overview and demonstration of the new features and functionality of SoundCheck 19, including the multichannel RTA, RT60 Room Acoustics module, AmpConnect 621 control, and more.

SoundCheck 19 New Features

SoundCheck 19 builds on recent releases with additional functionality for multichannel measurements, including the new Multi-channel RTA, WASAPI-exclusive mode and AmpConnect 621 control. The incorporation of room acoustics measurements offers increased capability for those looking to evaluate devices in real-world situations. Many of these features also add value on the production line, minimizing setup time, reducing the opportunity for user-errors and ensuring smoother operation in automated situations.

SoundCheck 19 New Features

Read on to learn more

For a full list of all SoundCheck features, including version 19, check out SoundCheck: What’s New?

A new multi-channel version enables viewing of multiple signal paths simultaneously. Spectrum settings such as gain, octave band, weighting, averaging and time-weighting can be set independently for each channel for complete measurement flexibility. The new Multi RTA also supports a power averaging calculation on the signal paths which can be used for spatial and sound power measurements.

The RT60 Room Acoustics module measures reverberation time and clarity of any room or space. This functionality is useful for quantifying how speaker(s) will interact with the acoustics of a particular type of room. SoundCheck offers extremely fast measurements using a continuous sine sweep with the Log TSR algorithm to obtain the impulse response. The reverberation decay curve is calculated from the backwards integrated impulse response.

SoundCheck now offers the option to operate in WASAPI-exclusive mode. The advanced interface offers superior communication with audio devices in recent versions of Windows, giving SoundCheck greater control over the audio stream. Multiple WASAPI devices may be used simultaneously, and it’s also possible to combine WASAPI and ASIO devices to increase channel availability.

SoundCheck 19 supports AmpConnect 621, Listen’s new high resolution (up to 192kHz) multichannel audio interface, exclusively configured via the SoundCheck 19 software. AmpConnect 621 features full plug-and-play functionality and TEDS support for automatic identification, configuration and calibration of microphones and accelerometers. SoundCheck 19 with AmpConnect 621 is a simple and cost-effective solution for automotive measurements with a 6-microphone array.

The new Diagnostic Window enables the user to suppress warning dialog windows when running a sequence and instead log the errors, warnings, and information in a separate diagnostic window. SoundCheck now allows use of a USB controller knob in both Windows and MacOS to adjust the SoundCheck Signal Generator.