Industry & Product News
Apple Announces AirPods Update and AirPods Pro with Spatial Audio Support
Apple's annual Worldwide Developers Conference opened with a series of spectacular announcements, updating all the company's operating systems: iOS 14, iPadOS 14, watchOS 7, and tvOS 14. WWDC20 will be remembered also for the major transition for macOS and the Mac to a completely new processor architecture. For the audio industry, this event was full of exciting announcements across all platforms, and the unveiling of a new AirPods firmware update with new hearing enhancement accessibility features, and bringing spatial audio support for AirPods Pro .    Read More
VB-Audio Software Releases the VB-CABLE Virtual Audio Device for Mac
VB-Audio, Vincent Burel's incredibly creative software company, announced that virtual cables are now available on macOS (10.10 to 10.15 64-bits). The application, already available for Windows, enables users to connect any audio applications inside the same Mac computer. VB-CABLE is a virtual audio device working as a virtual audio cable, where all audio coming in the CABLE input is simply forwarded to the CABLE output. Just what's needed to record any Audio application running on the Mac .   Read More  
Audioengine Introduces B-Fi Wi-Fi Multiroom Music Streamer
Audioengine was always recognized for its cool compact portable speakers with wireless audio features that brought a hi-fidelity feeling back to today's lifestyles, at reasonable prices. The company also sold a separate B-Fi Bluetooth transmitter so users could wirelessly connect their existing sources. Now Audioengine has stepped up the design and launched the B-FI Wi-Fi, a multiroom music streamer device with AirPlay 2 that is just the upgrade needed to get any stereo high-fidelity music systems streaming into the whole home .    Read More

Sound Semiconductor Expands IC Range with New Single and Dual VCA Chips
Sound Semiconductor announced single- and dual-channel VCA additions to its product lineup, the ProCircuit SSI2161 and the FatKeys SSI2162.The ICs are part of a family of affordable high-performance VCAs from the company, now offering a single, dual, and quad versions. The SSI2164 offers four VCAs in a compact SOP package with the lowest cost-per VCA, while the new SSI2162 is a versatile building block for high-performance audio applications, and the single-channel SSI2161 provides lowest noise .    Read More  

Nureva HDL200 Audio Conferencing System Now Shipping Globally
Nureva Inc., the innovator in advanced audio conferencing solutions, is now shipping its HDL200 audio conferencing system. This intelligent microphone and speaker bar designed for smaller spaces is the newest addition to the company's line of audio conferencing products. 4,096 virtual microphones provide full-room coverage to easily accommodate physical distancing requirements and ensure remote participants can hear every word .    Read More  

Lucid Audio Acquires Westone Audio, the Music Division of Westone Laboratories
A familiar name in in-ear monitors for athletes, musicians, music producers, and music enthusiasts, Westone Audio built a strong business with innovative products that have been praised for many years in its market segment. That division is also a part of a larger enhanced hearing health and communications business. For Texas-based Lucid Audio, the Westone acquisition perfectly complements its expansion strategy in the pro and consumer in-ear monitor business, following the acquisition of Etymotic in 2018 .    Read More  

New Speakerbench Online Tool for Assisting in Speaker Design Calculations
Speakerbench is a web-based application created by Jeff Candy (San Diego, CA) and Claus Futtrup (SEAS, Norway), combining several special-purpose modules aimed at low-frequency analysis and design of loudspeakers. According to the authors, the online tool is made available to whoever might find it useful, including the loudspeaker DIY community. The authors encourage user feedback and even invite software developers to implement the techniques .    Read More

Virtual ALTI-EXPO Recorded Sessions Are Now Available Online and Free to All!
Audio & Loudspeaker Technologies International (ALTI) was forced to cancel its ALTI-EXPO 2020 due to the global pandemic. So the organization looked for a way to serve Members and Exhibitors without risking travel. On June 15, there was a series of online sessions presented as a service to ALTI's members and the industry. Now, nine of the webinar sessions are available directly on ALTI's website. ALTI is already working on a new and expanded Virtual ALTI-EXPO 2 set for July 15 .    Read More  

Guest Editorial
Hans W. Gierlich
(HEAD acoustics)

Speech Quality in Conferencing Scenarios
Understanding All Optimization Requirements
While on the one hand, we experience the benefit of having communication possibilities anytime and anywhere and use all types of communication platforms allowing us to interact in virtual conferences without being present physically - we also experience significant variations in communication quality, especially when being involved in virtual meetings. The question is: What is communication quality and which factors distinguish good communication quality from poor communication quality?

When defining communication quality you will find that there are varieties of aspects in speech quality, which need to be considered from the user's point of view, such as listening speech quality, and associated artifacts, such as interrupted and distorted voice; the delay to transport the speech signal from one end to the other, hampering the conversational flow; echo and howling effects especially in multi-party conferences; not being able to interrupt conversational partners, and more.

Additionally, the user's environment and the user's behavior plays an important role. Adverse conditions, noise, and reverberation may impair the speech quality on all sides of a virtual meeting. User movements, non-optimum positioning of devices, and their effects on communication quality need to be understood. Perceptually, latency, speech intelligibility and listening effort, loudness, speech sound quality, talking effort and echo performance, double-talk performance, and localization performance are all relevant parameters deserving technical investigation.

These parameters are perceptually relevant and can be evaluated subjectively. However, for (objective) system test and product optimization,  procedures are required to help engineers in a lab-type environment. The instrumental procedures used nowadays to qualify and optimize products are based on perceptual investigations and can be applied with a good degree of confidence by engineers in the lab.

Laboratory-Based Testing
Technically, the conversational quality is determined by the quality of any device used in a connection. Transparency and compatibility of devices is key when interconnected. The quality of the communication terminal, the network quality, and the quality of the conference bridge are of equal importance.

The minimum requirements found in existing standards and which are typically applied by manufacturers of devices are insufficient and generally do not cover this complex scenario. For optimization, a variety of additional technical parameters can be measured and used.

The basic optimization process starts with the endpoints of the connection, the terminals - regardless of which type of terminal is used: handset or headset (wired and cordless), hands-free, conference system, smart speaker, PC, tablet or other smart devices.

Realistic Simulation of Real-Life Situations
In this context, it is also necessary to take into account the user behavior as well as the user's environment. Nobody can perform such tests in real-life situations, but fortunately there are laboratory-based solutions available.

Background noise simulation is important to validate the performance of noise cancellation and voice enhancement strategies for a variety of background noises found in daily life scenarios. ETSI TS 102 224 [1] specifies the recording and setup procedures as well as pre-recorded background noise for those simulations. Using an HEAD acoustics simulation system 3PASS allows this simulation for all types of terminals with acoustical interfaces. 

An identical setup can be used for the simulation of reverberation, which is of special importance in the sending direction. Reverberation may impair speech communication as well as speech recognition. A simulation method for lab-based testing with reverberation, according to ETSI TS 103 557 [2], is used for that type of simulation.

User behavior can also be tested in different ways for different devices. A motorized handset positioner is used for testing positional robustness with all type of handheld devices. The efficiency of noise cancellation can be evaluated and optimized by simulating various user positions. The goal is to find a good balance between loudness, speech sound quality and the amount of background noise reduction in various positions and for various noise and room conditions. In a similar way, the speech sound quality and the listening effort [3] can be optimized in the receiving side.

Testing Conversational Performance
Testing the robustness of echo cancellation requires a variable echo path during the tests. An almost soundless rotating reflector can be used in the nearfield. The conversational performance of devices is determined by the delay introduced and the seamless behavior in all types of double-talk situations with and without background noise. During double-talk, no artifacts should be observed, neither from switching or echo nor any performance decrease with background noise. The signal processing quality in a terminal mostly determines all these parameters and can be optimized in the lab. A very good overview about testing and performance requirements can be found in the ETSI standard series [4] and [5]. A setup example is shown in Figure 1.

Figure 1: VoIP conferencing test setup with headsets.

Testing of headphones follows the same principle. Various positions typical for users are chosen for the tests as described above.

Measuring Speech Coding Performance
In speakerphone mode (e.g., with hands-free, laptop, tablet and handheld devices) and with conference devices, user behavior impact and the acoustical environment are even more critical. The acoustical coupling between loudspeaker(s) and microphone(s) is strong, leading to potential echo problems. User movements affect echo canceling performance more than in handheld devices. The distance between the talker and the microphone is much higher, and as a consequence, room noise and room reverberation have a much stronger impact on the performance than in handheld mode. 

However, as with the handheld mode, similar testing strategies simulating reverberation and background noise ([1], [2]), user movement simulation by using a rotating reflector, and a turntable to rotate the device under test can be used. And the metrics used for qualifying are the same as in handheld mode. The parameters determining the quality from the user's point of view are almost the same.

Evaluating Network Performance
Speech coding performance in conjunction with network performance is essential for all types of endpoints including modems. Since most conferencing solutions are OTT solutions, no bandwidth guarantee is given and channel quality may vary depending on load conditions and routing. Lab-based testing is performed using a different type of network jitter and loss simulations applied to the speech codec. The parameters tested are listening speech quality and jitter buffer handling. With jitter and packet loss, it is key to limit the increase of the jitter buffer size while simultaneously keeping the speech quality high. This can be achieved by optimizing the jitter buffer handling and the packet loss concealment, which today is typically part of the speech codec used.

Help Is Available
All the procedures and setups described above are key in all HEAD acoustics' development work over the last few decades. Complete sets of automated test procedures and simulations are available for laboratory use, for all types of devices and configurations.
In addition, setups for the optimization of the complete transmission chain are available. There is big potential in quality increase if such advanced optimization strategies are used.

HEAD acoustics provides complete and automated test systems to bring the user's environment to the lab. The most advanced tests and simulation methods are available and can be used for device and system optimization. When successfully applied, a much better user experience for all systems can be realized than often found today.

HEAD acoustics developed ABLE (Assessment of Binaural Listening Effort), a method to predict perceived listening effort that evaluates the influence of background noise on speech signals.

[1]ETSI TS 103 224: Speech and Multimedia Transmission Quality (STQ): A sound field reproduction method for terminal testing including a background noise database, ETSI 08/2019

[2]ETSI TS 103 557: Speech and Multimedia Transmission Quality (STQ): Methods for reproducing reverberation for communication device measurements, ETSI 08/2019

[3]Gierlich, H.W.; Reimes, J.: Objective Listening Effort Evaluation, audioXpress 04/2020

[4]ETSI ES 202 737 - ETSI ES 202 740 series: Speech and multimedia Transmission Quality (STQ); Transmission requirements for narrowband @wideband VoIP terminals (handset, headset & hands-free) from a QoS perspective as perceived by the user, ETSI 03/2020

[5]ETSI TS 102 925: Transmission requirements for Super-Wideband/Fullband hands-free and conferencing terminals from a QoS perspective as perceived by the user, ETSI 10/2018 .

You Can DIY!
The TSM-100 - A Turntable Speed Measurement Device
By  George Ntanavaras
In this article audio electronics expert George Ntanavaras, a long-time contributor of original DIY projects for audioXpress, explains how to build a turntable speed measurement device using a microprocessor-controlled design that measures the speed of a turntable's platter. The project is based on the Arduino Uno hardware board and the Arduino software IDE, and uses a micro sensor manufactured by Omron to sense the platter rotation. The author shares all the details including code for this project, and for those interested he still has available a small quantity of PCBs and programmed CPUs to build the device. This article was originally published in audioXpress, June 2018 .    Read the Full Article Now Available Here
Voice Coil  Focus
More Developments in Loudspeaker Enclosure Materials
By  Mike Klasco
Following other articles on the topic in previous years, Mike Klasco writes about New Developments with Loudspeaker Enclosure Materials. In this report, Klasco once again shares his knowledge with loudspeaker enclosures and reports on the progress in enclosure materials and technologies in 2020. And if someone has interesting things to share about wood enclosures, composites, plastics, improved plastic-based formulas, ABS/PA (polyimide), thermoset and thermoplastic resins, bulk-molded and sheet-molded thermosets and more, it's certainly Mike Klasco. This article was originally published in  Voice Coil, March 2020 .    Read the Full Article Now Available Here

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