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Offline Menu (Working from home with SoundCheck #4)

In this short video, Cam Ruffle-Deignan explains how you can use the offline menu to experiment with analysis steps using previously-captured data. This can be treated as a scratch pad for testing out different algorithms and step configurations, and these be saved for later use in sequences.

Sequence optimization (Working from home with SoundCheck #3)

In this short video, Devin Vaillancourt explains ways in which you can optimize your SoundCheck sequences when working from home without full access to your equipment.

Using the SoundCheck Demo Viewer (Working from home with SoundCheck #2)

In this short video, Les Quindipan explains how to get the demo version of SoundCheck up and running when you don’t have your usual hardware available, outlines its functionality and makes suggestions as to useful things you can do using this version when you don’t have access to your lab.

Introduction – Getting the Resources you need (Working from home with SoundCheck #1)

In this short video, Steve Tatarunis explains how to get your SoundCheck system up and running from home, and what resources are available to help.

SoundCheck 18 New Features

Check out our short demo video for a brief introduction to all the new features in SoundCheck 18. These new features in SoundCheck 18 focus on automation and simplicity. Automation features include the ability to pass test configuration data to and from external programs, and control of MEMS interfaces via a sequence. Setup and test development is simplified with ‘plug and play’ functionality for Listen hardware, simplified gain control, and improved sampling rate management.

SoundCheck 18 New Features

Read on to learn more

For a full list of all SoundCheck features, including version 18, check out SoundCheck: What’s New?

Soundcheck’s new sequence parameter feature allows the user to pass test configuration data into the memory list from external programs using TCP/IP commands. By externally storing parameters such as limits, test levels, and test signals, a single sequence can be used for multiple products. Improved hardware setup enables you to plug in and make measurements faster. Listen and Portland Tool & Die Hardware are now true ‘plug-and-play’ which minimizes configuration time, particularly with multichannel interfaces. Simply connect your AmpConnect, BTC-4149 or other Listen interface via the USB cable and the software auto-populates parameters such as sampling rate and calibration values, and creates input and output signal paths. Multiple hardware items are stored within the software, so that they are immediately recognized when connected, and the software will automatically default to the correct device. Auto read and auto range gain settings are now easily accessible as drop-down options in the gain menu in the acquisition step editor, and auto-read is available in virtual instruments. When the gain is set to auto range, SoundCheck will automatically identify the correct level of gain to optimize the measurement signal to noise ratio.

For any hardware device, the user can specify the latencies for various sampling rates, either by entering them manually or importing from a file, and SoundCheck will automatically use the correct latency for any sampling rate specified in the stimulus editor. Digital I/O control is now a separate message step, which means that all controls for I/O settings are completely separate from other AmpConnect settings, minimizing the possibility of other parameters being changed on accident. The Portland Tool & Die MEMS microphone interfaces can now be fully controlled from within SoundCheck, offering faster setup and greater measurement reliability. TEDS Support (with compatible Listen hardware) enables automatic identification, configuration and calibration of TEDS microphones and accelerometers, saving time on initial hardware setup and whenever hardware is changed. SoundCheck 18 now includes WASAPI driver support in Windows 10, offering full multichannel support. Finally, the new Auto Delay+ algorithm offers increased accuracy for open loop measurements, especially in cases where the delay is longer than 1 second.

Use the Harman Target Curve to Predict Headphone Preference

Screenshot from SoundCheck showing the Harman Target Curve being used to predict listener preference ratings of headphones

The Harman Target Curve is used to predict listener preference of headphones

In their landmark papers “A Statistical Model that Predicts Listeners’ Preference Ratings of In Ear Headphones – Parts 1&2” presented at the AES 143rd in October 2017, Sean E. Olive, Todd Welti, and Omid Khonsaripour of Harman International introduced a model that predicted listener preference ratings of headphones based on the Harman Target Curve. We have created a SoundCheck sequence that measures any headphones and predicts the listener preference rating based on comparing its measured results to the Harman Target curve using this model. Listen acknowledges and thanks the authors of the Harman paper for providing the spreadsheet which is used as the basis for the excel template used in this sequence.

This sequence, inspired by the Harman research referenced above, applies the Harman target curve for in-ear, on-ear and over-ear headphones to a measurement made in SoundCheck to yield the predicted user preference for the device under test. The measurements are made in SoundCheck and then saved to an Excel template which performs the necessary calculations to produce a Predicted Preference score using a scale of 0 to 100. The spreadsheet calculates an Error curve which is derived from subtracting the target curve from an average of the headphone left/right response. The standard deviation, slope and average of the Error curve are calculated and used to calculate the predicted preference score. The sequence also provides the option to recall data rather than making a measurement, which saves time for engineers who already have large quantities of saved data, and enables historical comparison with obsolete products.

Check out our short video where we demonstrate this sequence in action

Get the test sequence for predicting headphone preference based on Harman Target Curves

Learn more about headphone testing using SoundCheck

References
A Statistical Model that Predicts Listeners’ Preference Ratings of In-Ear Headphones: Part 1—Listening Test Results and Acoustic Measurements
A Statistical Model that Predicts Listeners’ Preference Ratings of In-Ear Headphones: Part 2—Development and Validation of the Model
A Statistical Model that Predicts Listeners’ Preference Ratings of Around-Ear and On-Ear Headphones

 

SoundCheck 17 New Features

Check out our short demo video for a brief introduction to all the new features in SoundCheck 17. This new Windows/Mac release offers many features to simplify multi-channel and voice controlled testing, such as a new level and cross-correlation trigger, average curve/waveform post-processing functionality, the ability to easily read and work with multichannel wave files, multiple DC Connect control, and enhanced database options. On the usability side, SoundCheck 17 offers increased flexibility in color palettes, save to MATLAB option, and the ability to recall CSV formatted text files.

SoundCheck 17 New Features

Read on to learn more

For a full list of all SoundCheck features, including version 17, check out SoundCheck: What’s New?

Today’s modern audio devices have two important testing requirements: the ability to test a voice activated device with no analog input, and the ability to control and test multiple channels simultaneously, for example, microphone or speaker arrays. SoundCheck 17 contains a host of new features to facilitate this. For voice-activated measurements on devices with no analog input, such as smart speakers, wearables, hearables and smart home devices, the new level & cross-correlation ‘smart trigger’ offers improved performance. By using a chirp-based conditioning tone and searching for the exact log sweep frequency, it is more robust and less susceptible to false triggers than simpler level and frequency triggers.

To save time when testing smart devices where it is necessary to test microphone or speaker arrays, SoundCheck 17 can now directly read multichannel WAV files from the memory list, signal generator and stimulus steps. Also for testing multi-channel arrays, multiple DC Connects can now be controlled, independently configured, and used for data acquisition within SoundCheck. The new Average Curve/WFM post processing function which allows the average curve (or waveform) of a selected group of data in the memory list to be obtained, is particularly useful for power averaging selected curves, averaging curves from different spatial positions (e.g. microphone arrays), and complex averaging of multiple measurements with background noise. Finally, the database module has been enhanced and is now it 4x faster and 3x more space-efficient than previous versions. This is particularly important for testing modern audio products with multiple transducers (microphone arrays, multiple speakers, etc.), as these often generate large volumes of data.

Usability enhancements include improved color pallets which offer ultimate flexibility in defining colors for backgrounds, grids, cursors and graph lines. New default color palettes are included, and user-defined palettes can be saved as pre-set files which will be applied to any new display created. Multiple palettes can be saved, for example allowing different color sets for different applications. In addition, SoundCheck can now save any data (including memory list curves and Soundmap (time frequency analysis) data ) to MATLAB for additional processing. Data is saved as a standard MAT file and can be manually or automatically saved in this format.
Additional new features include support for the new APTX HD codec for high resolution Bluetooth testing, a 64 bit Demo / Data Viewer which enables measured data to be recalled and viewed without the need to own a separate license, and the ability to recall CSV files as well as TXT files.

A visit to Reviewed.com

Headphone Test using SoundCheckAbout Reviewed.com

Reviewed.com, part of the USA Today network, carries out quantitative reviews on a wide range of products including appliances, headphones, cameras, televisions and more. Since the beginning, their reviews have been built on the principle of using standardized scientific testing procedures to examine the performance of products, and a proprietary scoring method to ensure a level playing field amongst all manufacturers. Recently, I met with senior scientist Julia MacDougall, and received a tour of the facility and some insight into their headphone test methods, as well as a demonstration of their recently upgraded SoundCheck system.

The large brick building in Central Square, Cambridge, is in a part of town renowned for its young start up culture and unconventional work environments, so it’s no surprise to see a ping pong table next to the large, glass-walled conference room. However, once you get beyond the main lobby it is a labyrinth of test labs, each designed for testing a specific product. A room dedicated to camera testing features various test pictures on the walls, as well as 3d models with many moving and rotating parts to evaluate the camera’s capture of movement. Another lab was filled with massive flat screen televisions that were being tested for display performance, color measurement, luminance, contrast and more. Perhaps the most impressive was the appliance lab, where staff get to do their laundry while they work (in the interests of testing the washers), as well as working their way through many loads of white towels and stain strips that are marked with red wine, chocolate, sweat and more to scientifically evaluate the performance of the washing machines. Dishwashers, dryers, microwaves and ovens are also tested here, and a dedicated temperature and humidity controlled room contains many refrigerators filled with ‘dummy food’, the temperature of which is continuously monitored. The floor above the test labs is where their testers retreat to write up product reviews for their website, away from the whirr of tumble driers, swishing of dishwashers and stepped sine waves from the audio test lab.

 

The Audio Test Lab

The area that interested me the most was the smallest test area – the audio lab. Headphones are small and the test equipment is also compact, so a large room is unnecessary. Reviewed.com has been using Listen’s SoundCheck software since they first started looking for an objective way to test audio products back in 2007. Back then SoundCheck was being used for measuring mobile phones – smartphones were in their infancy, the next ‘hot product’, and Reviewed.com was the first review website to measure sound quality of a wide range of phones.

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Active Noise-Cancelling Headphone Battery Life Test

ANC battery life sequence screenshotThis SoundCheck test sequence measures the performance characteristics of Active Noise Cancelling headphones (ANC headphones) while monitoring the DC voltage and current provided to the headphone by its batteries. The sequence first measures the passive attenuation of the headphone before moving into a loop. The loop plays a 2 minute pink noise stimulus at high output level to accelerate battery drain. During this stimulus period, a current measurement is made by Listen’s DC Connect. Immediately following the stimulus, battery voltage is measured followed by acquisition and analysis of audio parameters (response, THD and THD Normalized). The active attenuation of the headphone is then measured followed by a series of post processing and Autosave steps. The looping continues until no output is detected from the headphone, when the device shuts down due to insufficient battery capacity.

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Headphone Active Noise Cancellation Test Sequence

Screenshot of the final test result for active noise cancellation headphone test, showing active, passive and total attenuation.This SoundCheck test sequence measures headphone active noise cancellation (ANC). It measures both the active and passive noise cancellation and calculates total attenuation over the operating frequency range of the headphones. Passive Attenuation is the amount of noise that is reduced at the ear simply by the headphones being worn. Active Attenuation is the amount of noise that is further reduced by turning on the device’s active cancellation circuits. Lastly, Total Attenuation is the combined reduction in noise from passive and active sources and is what the end user of the product will experience.

To calculate these metrics this SoundCheck test sequence performs three separate measurements using a Head and Torso Simulator and a small speaker which serves as a noise source. This is a simple, low-cost alternative to using a diffuse background noise environment with multiple speakers playing uncorrelated noise, although the sequence could be user-modified to support this.

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