AES Technical Committee

Audio for Telecommunications

Chair:	Bob Zurek	(Send E-mail)
Vice Chair:	Andrew Bright	(Send E-mail)

Areas of Concentration

1. Accuracy of Reproduction
2. System Acoustic Echo Control
3. Vocoders for Telecommunications and Their Effects
4. Component Induced Noise
5. Hands-Free/Speakerphone Design and Implementation
6. Hands-Free/Headset Design and Implementation
7. System Delay
8. Audio compatibility with External Devices
9. Mobile Handset Acoustics and Audio Quality
10. Wideband Audio Standard for Telephony
11. Noise effects and its control in telecommunications
12. Other telecom digital signal processing technologies
13. Variable Acoustic Load Impedance (Leak Tolerance)
14. Telecom Device and End-to-End Audio Testing
15. Voice over IP & Packetloss
16. Compliance body audio/acoustic education

Recent/Planned Activities

• Formative Meeting held on 12/1/01 at 111th Convention
• Meeting held on 5/11/02 at 112th Convention MOC, Munich Germany.
• Meeting held on 10/6/02 at 113th Convention Los Angeles Convention Center, Los Angeles, CA USA.
• Meeting held on 3/22/03 at 114th Convention RAI Conference and Exhibition Center, Amsterdam, The Netherlands.
• The First TC on Audio for Telecommunications Workshop was held on Sunday, March 23 2003 at 16:00. This was Workshop #7 at the 114th Convention of the AES. The title of the workshop was "HANDSET AND HEADSET TESTING - Beyond narrowband."
• Meeting held on 10/11/2003 at the 115th Convention Javits Center, New York, NY USA.
• Meeting held on 10/09/2005 at the 119th Convention Javits Center, New York, NY USA.
• Meeting held on 10/2006 at the 121st Convention Convention Moscone Center, San Francisco, CA USA.
• Meeting held on 10/06/2007 at the 123rd Convention Javits Center, New York, NY USA.
• Meeting held on 5/18/2008 at the 124th Convention Amsterdam, The Netherlands.
• Meeting held on 10/04/2008 at the 125th Convention Convention Moscone Center, San Francisco, CA USA.
• Next meeting will be Saturday October 10th at 5pm in room 1E05 of the Javits Convention center, New York, NY USA. This meeting will coincide with the 127th Convention of the AES.

Highlights From Last Meeting

• Highlights from 10/4/2008 meeting in San Francisco.
• Discussed validity of wide band telephony acoustic bandwidth and the feasibility of the current specification in realisitc mobile systems.
• Received and update on progress on ANSI and IEEE telephoney test standards.
• Collected information for the next "Trends" document.

Emerging Technology Trends

The trend in mobile telecommunications has been toward the creation of the phone as the center of the user’s personal network, and in some cases media center.

The last three years have seen portable handsets become complete multimedia devices capable of capturing and playing back high-quality audio and video. MP3 playback in devices has become commonplace, and content can be downloaded from both personal computers and the wireless

network. The audio playback can typically be directed to stereo headsets and often stereo speakers in devices that utilize head-related transfer functions to widen the stereo image and often reproduce 3-dimensional audio effects. There has also been a shift from wired to wireless accessories over the last few years as well. Bluetooth headsets have grown from a niche market in 2003 to a significant portion of the headsets sold today. In the handsfree car kit space, wireless solutions such as Bluetooth have overtaken the wired offerings.

In addition to the convergence of multimedia applications on the portable communications devices, there have also been significant advances in the audio processing for improved voice communication. There are now several examples of phones with noise-adaptive downlink speech

enhancement on the market. These devices adapt the downlink audio based on the environmental noise to provide the most intelligible signal to the user. There have also been continued improvements in the quality of noise suppression for uplink audio and echo suppression chains. Wideband voice communication has been implemented in VOIP systems and is planned to be introduced to circuit switched systems in the next few years.

On the transducer front nearly all devices have both private mode and speakerphone functionality. The trend in the playback transducers has been mainly in size reduction of commonly used dynamic speakers. The past three years have seen the implementation of the first semiconductor MEMS microphones in portable communication devices. While standard electret microphones continue to be the norm, the portable communication industry uses

the majority of the MEMS microphones being produced today.

The convergence of all of these technologies and the globalization of wireless telecommunications, have led to myriad standards for telecommunications audio. The combination of these standards has squeezed the design specifications of the devices eliminating some of the design opportunities that were available in the past. Limitations on headset volume in music devices in Europe has led in some cases to reductions in headset output and headset interface levels. Significant efforts have also been applied to designing the wireless handsets to be compatible with hearing aids in the United States, which has resulted in an order of magnitude increase in the devices useable by hearing aid users. These new standards have made design of devices that both meet the requirements while maintaining levels of audio quality expected by all of the consumers an increasingly difficult task.

Meeting Report:

These documents do not necessarily express the official position of the AES on the issues discussed at these meetings, and only represent the views of committee members participating in the discussion. Any unauthorized use of these publications is prohibited. Authorization must be obtained from the Executive Director of the AES: E-mail, Tel: +1 212 661 8528, Address: 60 East 42nd Street, Room 2520, New York, New York 10165-2520, USA.

2003-10-11     Meeting report 3/22/2003
Description: Minutes of the Techincal Committee on Audio for Telecommunications meeting held on March 22nd 2003 at the 114th AES Convention in Amsterdam.

Technical Report:

2003-3-21     Emerging Trends in Technology 1/2003
Description: Technical Committee on Audio for Telecommunications Report on Emerging Trends in Technology

Other:

2004-2-18     AES 114th W7: Handset & Headset Testing, Bob Zurek
Description: W7 at the 114th Convention discussed measurement of handsets and headsets, particularly from the perspective of telecommunications. Attached are slides presented by Bob Zurek at the workshop.

2004-2-16     AES 114th W7: Handset & Headset Testing, Paul Darlington
Description: W7 at the 114th Convention discussed measurement of handsets and headsets, particularly from the perspective of telecommunications. Attached are slides presented by Prof. Paul Darlington at the workshop. (Note: Slides are in html file, in the attached *.zip file.) Extract all files (using WinZip) to a local directory, and then open 'index.html' .

2004-2-16     AES 114th W7: Handset & Headset Testing, Joensson et al.
Description: W7 at the 114th Convention discussed measurement of handsets and headsets, particularly from the perspective of telecommunications. Attached are slides presented at the workshop by Soeren Joensson, Bin Liu, Lars B. Nielsen, and Andreas Schuhmacher.

2004-2-16     AES 114th W7: Handset & Headset Testing, Allen Woo
Description: W7 at the 114th Convention discussed measurement of handsets and headsets, particularly from the perspective of telecommunications. Attached are slides presented at the workshop by Allen Woo.

2004-2-16     AES 114th W7: Handset & Headset Testing, Hans Gierlich.
Description: W7 at the 114th Convention discussed measurement of handsets and headsets, particularly from the perspective of telecommunications. Attached are slides presented by Dr. Hans Gierlich at the workshop.

2003-3-21     Telecom Standards List
Description: List of Audio Related Telecommunications Standards

Committee Members

Khalid Sidiqi	Todd Beauchamp	Jim Bobisuthi
Jean-Baptiste Greuet	Robert Baum	Miikka Vilermo
Dave Yeager	Bob Cochran	Jonathan Lane
Joe Klinger	Christopher Struck	Juha Backman
Giles Davis	Jyri Huopaniemi	Bob Zurek
K . Allen Woo	Jason Linse	Dr. Scott K. Isabelle
Andrew Bright	Simone Koo	Peter Isberg
Michael Howes	Joerg Binder	Marc Ihle
Scott Mehrens	John Cozens	Stefan Geyersberger
Gary Spittle	John Oh	Jeff Anderson
George Pan	Dominic Oliveira	Osman Isvan
John Nygren	Hans Habberstad	Richard Barham
Pat Dennis

To request membership in this Technical Committee please e-mail the Chair by using the link above.