SC-04-08 meeting report, New York, 2017-10

Report of the meeting of the SC-04-08 Working Group on Measurement and Equalization of sound systems in rooms, of the SC-04 Subcommittee on Acoustics, held in New York, 2017-10-18

The meeting was convened by chair Peter Mapp.

As there was no formal meeting of the group at the previous convention in Berlin, there were no minutes to approve, other than Peter Mapp had agreed to chair the group.

Development projects

AES-X218 - "Measurement and calibration of sound systems in rooms."
The chair pointed out that since the last meeting in New York (31-10-2015) there has been no progress. Despite the agreement of those present at the New York meeting to comment on the list of parameters proposed at the meeting and assign themselves to writing groups relating to these parameters, no response whatsoever had been received. On this basis, the parent committee, SC04 had therefore debated whether to close the group but had decided to give it one more go as it was felt to be an important topic.

The Chair went through the list of agreed measurement parameters as below :

  • • Frequency Response
  • • Sound Pressure Level (SPL)
  • • Max SPL
  • • Coverage
  • • Speech Intelligibility
  • • Distortion
  • • Background Noise (Acoustical)
  • • System Noise (Acoustical)
  • • Reverberation Time
  • • Gain Structure
  • • Temporal Response / Impulse Response

After discussion it was decided to temporarily leave writing the section on Frequency Response, as it was understood that the InfoCom draft spectral balance standard was being revised and there was no point in duplicating effort. Additionally, it was agreed that the Temporal Response / Impulse response item would not be considered at the moment as there would likely be duplication with AES-X219 (Method of measurement for frequency and impulse response of sound systems in auditoria) though echoes / generation of focused late reflections may be considered.

* The size of room to which the project relates was discussed and although not restricted it was felt that the objective was for large rooms (as opposed to small rooms).
* Cinema could / would be a specific subset of the work.
* The scope relates to what to measure and how to measure not what the result should be (though some basic commentary may be provided).
* May need to split into basic & advanced tests, bearing in mind the likely test equipment that an average contractor is likely to have.

In order to make and maintain progress, the chair asked for volunteers to head up the writing of the topics listed above and set a deadline of the end of the year for initial drafts of the sections. The chair also commented that unless the attendees at the meeting took an active role, there was little point in them being there!

The table below lists the topics to be covered and writing group members:

Topic Task leader / author Comment
Frequency Response - Awaiting InfoComm draft (But keep thinking about how to do this)
Sound Pressure Level SPL Steve Martz A or C weighting? What signal(s) to use?
Max SPL Charlie Hughes Operating level definition ?
Coverage David Murphy NB InfoComm document
Speech Intelligibility Peter Mapp -
Distortion Hughes and Murphy David Murphy - electronic distortion
Background Noise (Room) Neil Shaw -
System Noise (Acoustic) Neil Shaw System noise transmitted into room
Reverberation Time Eddie Brixen Inc EDT etc (ISO standard) Use of SS for excitation?
Gain Structure Bruce Olson -
Temporal Response - In Abeyance
Room Acoustic Analysis Peter Mapp Will probably include Impulse Response
Test Equipment Required & mic locations / types etc - Should be covered in individual sections but general discussion/ section probably required

Working Group members are to provide outline / draft text ASAP and by Dec 26 at the latest. The Chair will pursue Working Group members to provide their respective contributions.

A template which can be used for document development can be found at:

If others not present at the New York meeting would like to contribute their expertise & material, and if they have a particular topic in mind, then please contact Peter Mapp.

AES-X219 "Method of measurement for frequency and impulse response of sound systems in auditoria"
Project remains postponed, as per 2015 NY meeting, until there is some output of X218, which may or may not involve impulse response


Nothing to report.

New Projects

No new projects were proposed.

New Business

No new business was proposed.

The next face-to-face meeting will be schedued in conunction with the AES 144th Convention in Milan, Italy, 2018-05.

Virtual meetings will be held as required in advance of the Milan meeting once some content has been developed for the group to discuss.

AES - Audio Engineering Society