[Last printing 2002-08-13]

Audio Engineering Society Standards Committee

May 2002 report of SC-04-04

Report of the SC-04-04 Working Group on Microphone Measurement and Characterization of the Subcommittee on Acoustics meeting, held in conjunction with the AES 112th Convention in Munich, Germany 2002-05-11

Chair D. Josephson convened the meeting. The agenda and the report from the previous meeting were approved as written.

Current development projects

AES-X85, Detailed Professional Microphone Specifications

Discussion was concerned with recommendations to IEC TC100 in regard to the upcoming revision of IEC 60268-4. Mr Werner introduced the document (???), which includes the revisions suggested by the German and Japanese national committees. He explained that the IEC planned to release the revision of IEC 60268-4 as a call for vote, the changes from the 2nd edition being thought minor.

The chair apologized to Mr Werner for not having brought forth a more timely response from SC-04-04 in regard to this revision. It has been discussed in several recent meetings, and members had been asked to comment on the standard and its proposed changes, however no progress had been made. There remain several items of concern to the members however, principally in the area of performance measurements of pressure-gradient directional microphones. The chair moved that SC-04-04 work through the AESSC liaison with TC100 to strongly recommend that IEC release the proposed updates to IEC60268-4 as a Call for Discussion rather than a Call for Vote, so that some of these concerns could be addressed. This was agreed by all present. The chair will summarize the issues with which conflict is found and post this to the reflector by 2002 June 15 so that the Secretariat can take appropriate action with IEC liaison points. The chair is to explore with the Secretariat options for effective recommendations to IEC.

The completion date for AES-X85 was to 2005. Current goal is a recommendation to IEC TC100, date 2002-06.

AES42-R, Review of AES42-2001: AES Standards for Acoustics -- Digital interface for microphones

The chair reported on the earlier meeting of SC-04-04-D to discuss project AES42-R. The coaxial digital mic interface option was discussed, this time with the participation of Frank Chilinski, who had been unable to attend the 04-04-D meeting. Some of the same issues regarding powering and the potential for damage to legacy equipment, for example, were discussed as had already been discussed in the development of AES42. Further discussion will take place on the SC-04-04-D reflector which will hopefully lead to a consensus on a revision of AES42.

The current goal for AES42-R is for a PCFC of a revision with a target date of 2002-10.

AES-X62, Psychoacoustics of Microphone Characteristics

AES-X63, Time-Domain Response of Microphones

These two projects have not yet been addressed by the task group which handles them. The chair will check with the task group chair to determine whether these projects should be continued or retired.

AES-X93, Recommendations for Revisions of IEC 61938 Clause 7

A recommendation to IEC in 2000-12 has been produced which has been reformatted as a proposed working group draft (PWD) for release as an AES standard or information document.

There was some discussion about modifications which should be done before it was released as a CFC. It was agreed to eliminate normative references to P24 powering and make certain editorial changes. The chair will post the resulting draft to the SC-04-04 reflector by 2002-06-15 for discussion by members.

The project intent should be changed to "standard or information document" with a 2003 date for completion. The current goal remains a PCFC for 2002-10.

New projects

The chair mentioned a discussion initiated by attendees at the Technical Committee on Microphones and Applications meeting 2002-5-10 in which the need was expressed for a standard describing interface characteristics for OEM microphone capsules. This is specifically needed for interfacing to wireless microphone transmitters and other devices not using the usual balanced interfaces intended for use with long cables. The chair reported that those at the TC_MA meeting were intending to form a task group which would then initiate a new project request, but that the work had not yet begun.

New business

There was no new business.

The next meeting is scheduled to be held in conjunction with the 113th convention in Los Angeles, CA, US on 2002-10.

Back to top
Back to meeting reports

For more information about standards activity: standards@aes.org
AES Standards Home

(C) 2002, Audio Engineering Society, Inc.