AES Technical Committee:

Audio for telecommunications

Mission Statement


* * Dec. 12th 2022: the TC-AT has been de-activated indefinitely due to a lack of available volunteer time * *

The mission of the Technical Committee on Audio for Telecommunications is to deal with audio quality issues as they arise in the field of telecommunications. The intent of the committee is to provide guidelines for the design and integration of the audio components of telecommunications systems, to advise industry standard organizations on the audio issues presented by new technologies and telecommunication formats, and to disseminate information regarding telecommunication audio issues to the membership as applicable. It is the goal of the committee to ensure that audio quality and intelligibility are retained as devices decrease in size and new formats are created. The committee will concern itself with both the infrastructure and consumer ends of telecommunications systems as they affect the total system’s sound quality.


Vice Chair

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
  • 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.
  • Meeting held on 10/10/2009 at the 127th Convention Javits Center, New York, NY USA.
  • Meeting held on 11/4/2010 at the 129th Convention Convention Moscone Center, San Francisco, CA USA.
  • Christopher Struck gave a tutorial session on “Telephonometry: The Practical Acoustics of Handsets, Headsets, and Mobile Devices.” on October 22nd 2011 during the 131st convention in New York.
  • Meeting held on 10/22/2011 at the 131st Convention Javits Center, New York, NY USA.
  • The TC_AT organized a workshop on “Audio Hardware in Smartphones” at the 132nd convention in Budapest chaired by Antti Kelloniemi on Thursday, April 26 2012.
  • Meeting held on 4/27/2012 at the 132nd convention in Budapest, Hungary.
  • Meeting held on 10/28/2012 at the 133rd convention in San Francisco, CA, USA.
  • The TC_AT has organized a workshop on “Multi-Microphone Applications and Testing in Telecommunications Systems” chaired by Bob Zurek. The workshop took place at the 133rd convention in San Francisco on Monday, October 29.
  • Meeting was held at the 134th convention in Rome.
  • Meeting was held on 10/17/2013 at the 135th Convention Javits Center, New York, NY USA.
  • Christopher Struck presented a product design session PD3: Telephony: An Introduction to the Acoustics of Personal Telecommunications Devices on Oct 19th 2013 during the 135th Convention.
  • Meeting held on 10/09/2014 at the 137th Convention, Los Angeles Convention Center, Los Angeles, CA USA.
  • Meeting held on 9/29/2016 at the 141st Convention, LA Convention Center, Los Angeles, CA USA.
  • Meeting held on 5/22/2017 at Maritim Hotel, Berlin, Gremany

The trend in mobile telecommunications across the globe has been towards devices that are the mobile window into a person’s digital universe. In 2013 smartphones outsold feature phones globally for the first time on a unit basis. Several companies have focused efforts on creating inexpensive smartphones for the emerging markets, where, in many cases, these devices may be the only link those consumers have to the internet and the rest of the world. This expansion has resulted in devices that have many more communications bands and codecs than we have had in the past. It is not uncommon to find single devices that will communicate via UMTS, GSM, CDMA, LTE (VoLTE), and WiFi (VoIP). Some of these modes of communication have to support multiple voice codecs for each mode depending on the network or service provider. In all cases the switching between modes and performance of the system must be seamless, as past performance is no longer acceptable to the consumer. After 2013, mobile communication using VoIP and video conferencing apps has increased in accelerating pace.

From a voice quality standpoint, the AMR Wide Band codec is in widespread use globally, and the 3GPP EVS (Enhanced Voice Services) codec was finalized in 2014 and the first commercial deployment took place in South Korea in 2015. Demands for IP based communication also in poor networks have caused a rising interest in low bitrate voice codecs. The audio recording capabilities of the devices have improved to offer high bit rate and 24 bit capture in some cases. There are also many products out on the market that allow multichannel audio recording via internal microphone arrays to compliment the video recording on the devices. Use of stereo or spatial audio also for communication applications was increasingly studied in scientific research during the first decade of 2000. The first commercial applications have emerged, and we can see this as one trend that may change the way we communicate, together with the rise of technology and applications for augmented or virtual reality.

Voice controlled user interface in the mobile devices has evolved to Virtual Personal Assistants that extend to other platforms as well. Interaction with Natural Language is also coming to chatbots that are used for automating business processes like ordering a pizza over a phone call. Communication with these virtual assistants sets different requirements to smart phones and VoIP systems than what was common with human to human calls and new technologies are being developed to raise the quality of these features. We can estimate that in near future using a mobile device for voice communication between a user and a digital assistant or a bot will be as typical as communication between humans. This communication will happen both through the same signal paths as normal voice communication and through dedicated paths, using signal processing and coding optimized for voice recognition engines.

Advancements in usability in all environments have come in the form of noise adaptive technology in voice call, content playback and voice control. Voice communication and voice recognition have benefitted from algorithms that adapt uplink noise reduction or algorithm parameters based on noise type and level. This becomes even more important when voice control and new types of endpoint devices emerge. Smart speakers or communication hubs for homes, conferencing phones for office environment are used from further away compared to personal mobile devices, so signal to noise ratio may be poor to start with. Likewise downlink audio and content playback have benefitted from noise adaptive algorithms. Another new feature that assists the usability in various environments has been the use of smart amplifier technology. The technology constantly monitors the content and the speaker to produce optimal loudness or bandwidth, while maintaining safe drive levels for the speaker. This technology paired with new high voltage amplifiers work together to produce impressive audio quality in many environments.

On the content side of the business, the trend has been from localized content to cloud based content. This has allowed the consumer to consume the same content across all devices, which has posed challenges in the small power conscious mobile devices.

The move from portable phones with a few extra features to the mobile hub of the consumer’s digital world, are reflected in the standards world where the scope of standards as well as their names have had to change to keep up.

This time, TC_AT didn’t organize any workshops or tutorials. Also, there is no plan for such activities for the 135th convention.


In the meeting, we started planning of a workshop for the next international convention in Europe (136th, spring 2014). The topic could be about recent development in speech codecs used both in circuit switched speech and in Voice over IP communication.


Other discussed topics covered the apparent mismatch in broadcast and telecom audio technology development and in novel use cases for smartphones as handheld recorders of sound and video, as video streaming tools, and so on.

Highlights from October 9th 2014 meeting in Los Angeles.

The first half of the meeting was used to discuss the upcoming Emerging trends report (see below).

The rest of the meeting was spent discussing upcoming activities of the technical committee. The committee is planning to organize a workshop for the 139th convention in New York. The workshop will cover the technical challenges in designing the new mobile computing/entertainment/communication platform that the mobile phone has become from various points of view. Panelists will include engineers discussing hardware, software, chipset, codec, environment, and test perspectives.

Attendees: Giles Davis,; Steve Temme,; Jacek Stachurski,; Markus Vaalgamaa,; Phill Williams,; Frederik Nagel,


Discussed possible workshop on speech coding. Dr. Nagel suggested Fraunhofer could host in NYC next fall.

– HD Voice

– Standardization

Additional topics:

– Listening efforts for telecommunications, i.e. ease of understanding speech.

o Intelligibility

o Natural sounding

o Fatigue: High THD, High RT60, Cognitive load is measurable

– Follow-on discussion from ITU-T to our workshop

– Nagel mentioned topic: Artifact Perception

o In the first months of life, humans can hear all phonemes for all languages. But depending on what language is spoken around the baby, a portion of the phonemes are not reinforced, forgotten, and then become difficult or even impossible for adults to hear. Might there be some distortion artifacts that native speakers of some languages can hear, but those speaking other languages can not?

12:05 Opened, 12:55 closed


Participants: Antti Kelloniemi (Microsoft), Kalle Koivuniemi (Huawei Technologies), Juha Backman (Hefio), Frederik Nagel (Fraunhofer), Stefan Gustavsson (Qualcomm), Paul Fleetwood


1. Introductions


2. Planning


Current plans:

New York would have a workshop or tutorial about new TC codecs.

Milan would have a workshop or tutorial about new testing methods.


Paul: Boiler room is an example of 24 h live broadcasting and interaction between concurrent music events. Perhaps this could be an area to explore, like a workshop about small delay VR telepresence applications of the future, maybe in 2018 US convention. Frederik: Fraunhofer, Dolby could provide input on communication audio for VR and multi-channel.


Frederik: Tutorial of distributed music performance history (How technology has enabled that). Frederik has contacts to professors who could ask students to look at the topic and present. Juha: Milan has a history of early broadcasting of live opera performances, so it would be a great venue for a paper about this. This could attract creative people to hear about technology they are using or could use.


Stefan: Everything is nowadays about TC because cloud is so ubiquitous and many things go through it. One topic for a workshop could be the definition of TC in general – what it is and isn’t nowadays.


Stefan: Audio in IOT and voice recognition is a great topic. What is the difference between human to human and human to machine TC?

Requirements for IOT devices can be conflicting and not even public, which makes independent device development hard. There could be a standard for voice assistant device performance requirements to help the industry to align. Privacy issues are also of concern. Beam-forming and number of microphones are key items. Another angle is Ultra-low bitrate codecs and their reliability. How do they work with IOT?


Antti: An old workshop talked about audio design for mobile devices in general and proved to be a success. A similar exploration of for example military headsets and emergency communication systems could prove interesting as the requirements are so different from mobile / consumer communication device use cases. A military specialist of communication could give a very interesting presentation about this area. Frederik: Jan Holub is working on NATO voice communication Intelligibility topics and therefore a potential speaker. Antti also has contacts to explore.

December 12th 2022. (17:00-18:00 CET)



Antti Kelloniemi (Co-Chair)

Kalle Koivuniemi (Co-Chair)

Giles Davis

John Grant

Christopher Struck

Juergen Herre (TCL Chair)

Jayant Datta (TCL Vice-Chair)

Rafael Kassier (TCL Vice-Chair)



It was decided to de-activate the TC-AT indefinitely due to a lack of available volunteer time.

(Tele)communications work continues within the AES TC-AA Subcommittee on Voice Communications.

The TCL thanked Antti Kelloniemi and Kalle Koivuniemi for their past efforts, and relieved them of their responsibilities.

Members will be notified in due course.

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: Email, Tel: +1 212 661 8528, Address: 551 Fifth Ave., Suite 1225, New York, New York 10176, USA.

2012-6-11     Meeting report 27 April 2012
Description: Minutes of the Technical Committee on Audio for Telecommunications meeting held on April 27th at the 132nd Convention in Budapest, Hungary

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.

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

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

Andrew Bright
Giles Davis
Christopher Struck
Marc Ihle
Khalid Sidiqi
Dr. Scott K. Isabelle
Antti Kelloniemi
Rivanaldo Oliveira
Bob Zurek
Juergen Herre
Peter Isberg
John Grant
Miikka Vilermo
Roy Silverstein
Pat Dennis
Frederik Nagel
Juha Backman
Gerald Schuller
Kevin Gross
Dominic Oliveira
Robert Baum
Kalle Koivuniemi
Stefan Gustavsson
Luke Goodloomis

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