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The Future of Audio Measurements – SoundHub Denmark

Weds May 25th, 8.30-12.30

Presenters: Steve Temme, Listen Inc.; Michael Trolle, VibrAkustik

Join us at SoundHub in Struer for a great day of presentations and discussion on the latest in audio measurement. The presentations will cover a variety of audio test topics including the end of line testing for improved efficiency and yield, measurement in real-world conditions, free-field measurements without a test chamber and more. There will also be consultation time when we are happy to answer your questions or discuss any aspect of audio test. This event is highly relevant for anyone needing to test audio products, both in R&D and production.

Schedule

8.30-9.00: Check-in, coffee & Welcome by VibrAkustik & Sound Hub Denmark (Michael Trolle and Rie Kold Pripsø)

9.00-9.30: Perceptual distortion measurements

9.30-10.00: Accurate measurement of headphones and hearing assistance devices under real world conditions

10.00-10.30: Coffee and discussion time

10.30-11.00: New features in SoundCheck version 20

11.00-11.30: Free-field speaker measurements without an anechoic chamber

11.30-12.30: Consultation time: Bring us your audio devices and your measurement challenges and we’ll discuss your measurement options and demonstrate how your devices can be measured

Note: there will be live demonstrations on all topics, and a display of hardware for a complete measurement chain including fixtures, measurement microphones and sensors, audio interfaces and turntable.

Detailed Content Information

Perceptual Distortion Measurements: Perceptual distortion measurements enable production line yield to be increased by rejecting only devices with audible Rub & Buzz defects rather than any distortion defects, and Listen’s new enhanced Perceptual Rub & Buzz (ePRB) algorithm is the first to perform even better than the human ear! Through proprietary noise reduction technology and advanced perceptual algorithms, its performance in a noisy factory environment is comparable to the performance of a trained listener under normal listening conditions. Learn more about the science behind this algorithm, see the results, and learn how to implement it in your end-of-line tests.

Accurate Headphone Measurements in Real World Conditions: In this demo-focused session, we will demonstrate how to accurately measure Headphones and Hearing Assistance Devices under real world conditions with real world signals such as speech and music. For example, we will demonstrate, in real time, how to adjust the headphone fit for a proper seal on the head and torso simulator and measure headphone ANC with real background noise with our Multi Signal Real Time Analyzer

New Features in SoundCheck: The newly released SoundCheck 20 is at the forefront of audio measurement with new features for multichannel and communications, increasing its capabilities for audio measurement of smart speakers, infotainment systems, headphones and hearables, and other voice-activated and multichannel devices. In this 30 minute session, we will demonstrate the new features and explain how they are used for testing a variety of audio products and applications.

Free-field Speaker Measurements without an anechoic chamber: Can’t afford or get time in an anechoic chamber? That’s not a problem if you have SoundCheck! In this practical session, we will demonstrate a method first developed by Listen president Steve Temme back in 1993, known as the ‘splice’ technique. This measurement technique is easy to configure and enables you to make highly accurate free-field measurements in an ordinary room, avoiding the expense of an anechoic chamber and enabling measurements in your home or office.

 

SoundCheck 20 Released: ePRB, Features for communications testing, POLQA, Multichannel enhancements and more

SoundCheck 20, Listen’s flagship audio analysis software, introduces a new 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.

The new enhanced Rub & Buzz algorithm is a reliable and repeatable perceptual method for 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 algorithm, new research offers refinements that improve listener correlation and new, patent-pending, noise reduction technology offers unrivaled repeatability and reliability for end-of-line use. In fact,this algorithm performs like a human ear under normal listening conditions with the background noise of a manufacturing environment! SoundCheck measures perceptual Rub & Buzz using the same stepped sine wave, simultaneously with other end-of-line measurements, enabling this valuable analysis to be added to production line tests with no extension in test time.

Two of SoundCheck’s virtual instruments, the multichannel RTA and the Signal Generator, have been significantly upgraded. The multichannel Real Time Analyzer now includes expanded functionality for real time observation of audio signals. It displays multiple channels simultaneously, and offers real time calculation and display of channel, 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. RTA curves are now seamlessly integrated with SoundCheck’s standard graphs and can be dragged and dropped into any graph for easy comparison to limits and reference curves. This is useful for quick comparisons to reference standards or golden units, tuning automotive infotainment systems, and more.

An overhauled signal generator brings additional functionality and simplified operation, particularly when using wav files. In addition to standard audio stimuli (sine, white noise, pink noise, etc.) 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 level can be referenced to Peak, dB or RMS. The signal can be equalized in real time, and custom EQ curves applied, which is useful when using a non-flat source such as a mouth simulator. A specific portion of a waveform can be selected to play, either by selecting a start and stop time in seconds, or by examining the waveform, and signals can play for a fixed duration, a fixed number of times, or in a continuous loop. Outputs from 2 or more signal generators can be mixed on the same channel, and waveforms from multiple signal generators can be synchronized, or delayed for phase control during playback.

The optional POLQA (Perceptual Objective Listening Quality Analysis) module brings Opticom’s POLQA 3 algorithm, implementing the ITU-T P.863 standard, right into SoundCheck, where it can be used for perceptual measurements of speech degradation in communications applications ranging from telephones to smart devices. Used just like any other analysis step in a sequence, this is a fast and cost-effective alternative to a panel of human listeners. In addition to speech degradation measurements, it may also be used to assess the impact of noise reduction algorithms, evaluate bluetooth degradation due to packet loss, or to analyze distortions introduced into the audio path.

Several new features expand the software’s post-processing capabilities for testing communications devices. These include batch processing of external files, a silence stimulus step, and RMS level versus time and histogram post-processing steps. A pre-written test sequence for categorizing Doubletalk performance to two international standards, ITU-T P.502 and ETSI TS 126 132 (part #3114), from communications expert John Bareham, is also available. Other enhancements include a stimulus editor upgrade, the ability to export multiple SoundCheck recorded waveforms to a single multichannel wav file and a hardware reset option for quickly changing audio interfaces or restoring hardware to a known configuration.

Enhanced Perceptual Rub & Buzz Event – Asia Edition

March 24, 2022. 10:00am China time

Listen continues to lead the way in perceptual distortion measurements with our new Enhanced Perceptual Rub & Buzz algorithm. This new product, based on years of original research, offers unrivaled repeatability, reliability and correlation to human hearing, making it an unbeatable solution for end-of-line perceptual audio test.

Our launch event will include live demonstrations, results, technical explanations and more. Be the first to know. Sign up below.

Listen 凭着新的增强型感知摩擦音算法(Enhanced Perceptual Rub & Buzz algorithm)继续引领著感知失真測量。這種基於多年原始研究的新產品提供了無與倫比的可重複性、可靠性和与人类听觉的相关性,使它成為生產線末端感知音頻測試的無與倫比的解決方案。

我們的發布活動將包括現場演示、結果、技術解釋等。 成為第一個知道最新資訊的人。 请在下面登记。

 

Measuring Max SPL versus Frequency

This sequence measures the Max SPL of a transducer versus frequency that a device can play back with acceptable distortion. It is particularly valuable for designers using DSP algorithms to optimize the performance of their speakers.

It characterizes the Max SPL of a transducer by setting limits on specific metrics (THD, Rub & Buzz, Perceptual Rub & Buzz, Input Voltage and Compression) and then driving the transducer at a series of standard ISO frequencies, increasing the stimulus level until the one of the limits is surpassed. The sequence begins by measuring the frequency response and impedance of the DUT. The user is asked if they wish to use the -3dB from resonance frequency as the test Start Frequency or manually enter another value. The user is then prompted to enter a Stop Frequency, initial test level and limit values for the metrics of interest. The sequence then plays the stimulus Start Frequency in a loop, increasing the level +3dB with each loop iteration until one of the limits is exceeded.  The stimulus level is then adjusted -3dB and the sequence continues to a second loop which increases the stimulus level +0.5 dB with each loop iteration until the limit is exceeded. At this point, the limit results are saved to an Excel file, the stimulus frequency is incremented by a constant multiplication step and the process is repeated until the Stop Frequency is achieved. Every time the main loop is completed, the individual SPL and Stimulus Level x-y pairs are concatenated to master curves. At the end of the sequence, the Max SPL and Stimulus Level curves are autosaved in .dat format.

More

Measurement of Harmonic Distortion Audibility Using A Simplified Psychoacoustic Model

A perceptual method is proposed for measuring harmonic distortion audibility. This method is similar to the CLEAR (Cepstral Loudness Enhanced Algorithm for Rub & buzz) algorithm previously proposed by the authors as a means of detecting audible Rub & Buzz which is an extreme type of distortion[1,2]. Both methods are based on the Perceptual Evaluation of Audio Quality (PEAQ) standard[3]. In the present work, in order to estimate the audibility of regular harmonic distortion, additional psychoacoustic variables are added to the CLEAR algorithm. These variables are then combined using an artificial neural network approach to derive a metric that is indicative of the overall audible harmonic distortion. Experimental results on headphones are presented to justify the accuracy of the model.

Authors: Steve Temme, Pascal Brunet and Parastoo Qarabaqi
Presented at the 131th AES Convention, San Francisco, 2012

Full Paper