Report of the SC-04-04 Working Group on Microphone Measurement and Characterization of the SC-04 Subcommittee on Acoustics meeting, held in conjunction with the AES 117th Convention in San Francisco, 2004-10-29.

The meeting was convened by chair D. Josephson.

The agenda and the report of the previous meeting, held in Berlin 2004-05-09, were approved.

Open Projects

AES-42R, Review of AES-42-2001: AES Standards for Acoustics - Digital Interface for Microphones.
SC-04-04-D chair C. Langen gave a report on the meeting of that task group, which has been resolving some of the last items being discussed for the revision of AES42. At present all outstanding issues have been resolved at the task group level and the revision will be presented to the WG for review. The principal changes are in the definition of additional operating features in the command structure so that processing internal to the microphone may be controlled from a mixing console, for example.

Development Projects

AES-X85: Detailed Professional Microphone Specifications
Work has been progressing on the project AES-X85 within task group SC-04-04-E. Because of the general interest in this work, task group leader David Josephson has been holding meetings concurrently with the working group meetings, which was again the case with this meeting. The present phase of the project is a round-robin test of 10 microphones provided by different manufacturers. By the time of this meeting, the group of microphones had been sent to eight of those microphone manufacturers where a defined protocol of measurements had been taken by each company in order to compare results. So far, six of the eight manufacturers had posted their results to the task group document site, two had not yet done so, and two had not yet completed the tests.

M. Opitz of AKG prepared a spreadsheet showing the results obtained in the key test areas by each of the companies. There are some significant differences in the results obtained by the companies: the meeting felt that, at the very least, the testing methods suggested in IEC 60268-4 are not sufficiently well defined that equally competent labs will get equivalent results. Discussion of these procedures will continue on the reflector and the remaining companies should have data posted in time for the next meeting.

New projects

No new projects were requested.

New business

There was no new business.

The next meeting will be scheduled in conjunction with the AES 118th Convention in Barcelona, Spain, 2005-05