SC-04-08 meeting report, online meeting, 2023-05

Report of the meeting of the SC-04-08 Working Group on Measurement and Equalization of sound systems in rooms, held online, 2023-05-24

Vice-Chair David Prince convened the meeting.

In attendance were David Prince, Charlie Hughes, John Woodgate, Tomlinson Holman, Eddy Brixen, Rich Cabot, Jeff Berryman.

The formal notice on patent policy was read.

Minutes of previous meeting online, 2022-10-12 were reviewed with the group.

A brief update on the status of group leadership was given where David Prince will fill in for Peter Mapp until Peter is able to return.

Projects assigned to this group but not mentioned here had no action requested or required - see for details.

Development projects

AES-X218: Measurement and calibration of sound systems in rooms.
The original path of the standard had a section for MaxSPL as part 4 so this was discussed first due to participant availability. Charlie Hughes summarized the status of AES75 adoption and it’s potential support for the x218-4 (MaxSPL at seating locations). Adoption is slower than anticipated but growing. Since AES75 is designed for free field assessment, it’s use might be limited once one is closer to boundaries in a typical room condition. AES75 may be a useful input but is not expected to be a ‘silver bullet’ with respect to part -4. The group is encouraged to gain experience where possible in comparing free field to in-situ measurements and share data.

X218-3 Frequency response and Intelligibility measures is still under development. David Prince will check with Peter Mapp on progress. Further informative documents were suggested by Eddy, Charlie, and Tomlinson and will be uploaded to the x218 folder. These include ISO, AVIXA, and Nordtest docs. Eddy notes that the Nordtest doc is 23 years old and due for revision (which we may be able to inform or supercede) but it has held up reasonably well over that time period. It tends to be very dense with measurement locations and may benefit from some statistically informed reduction methods. The document NT Acou 108 is available in the x218 folder. Tom notes that ISO3382 is ’squirrely’ in places but could help to inform and be a substantive reference. Charlie Hughes will reach out to AVIXA standards for info on upcoming docs.

X218-2 General Room reverberation measurements. Once the additional documentation is in place, this will be developed further. Existing reference information

X218-1 The base draft of the noise section of the document is on the site but still needs some minor revision and updating.

AES-X219: Method of measurement for frequency and impulse response of sound systems in auditoria
Project remains postponed until there is some output of X218


Liasons with AVIXA may be discussed pending Charlie Hughes discussions. To the best of his knowledge, Eddy notes that information use of the Nordtest document should be permitted.

New Projects

No new projects were proposed.

New Business

Rich and David will organize the document exchange folder to make it a bit more manageable. Rich Cabot requests regular meetings to drive these standards faster. David Prince will organize bi-weekly meetings.

The next meeting will be held online in October 2023, scheduled in conjunction with the AES 155th Convention.

AES - Audio Engineering Society