SC-04-03 meeting, Online, 2020-10

Report of the meeting of the SC-04-03 Working Group on loudspeaker modeling and measurement of the SC-04 Subcommittee on Acoustics, held online, 2020-10-05.

The meeting was convened by chair S. Hutt.

Present were Richard Cabot, Steve Hutt, Thomas Lago, David Murphy, David Andrews, Geoff Hill, Neil Shaw, David Robb, Lon Neumann, Ismo Pankalanen, Thomas Gmeiner, Merlijn van Veen, Roger Schwenke, Ian Robertson, Steve Thompson, Brian McLaughlin, Charlie Hughes, David Prince, Balazs Kakonyi, Bob Snelgrove, David Blore, Brian Vessa, Alex Voishvillo, Kurt Graffey.

The formal notice on patent policy was read.

The agenda and the report of the previous meeting, held in online, 2020-05-28, were approved as written.

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

Open projects

AES2-R Review of AES2-2012: AES standard for acoustics - Methods of measuring and specifying the performance of loudspeakers for professional applications - Drive units
Scope: This Recommended Practice establishes a set of primary specifications to be followed by manufacturers in describing loudspeaker components used in professional audio and sound-reinforcement system design.

Status: Reaffirmed in 2017

Discussion: There has been no significant activity since the last meeting. The group decided that the topic of SPLmax measurements on raw transducers in free air as not relevant however maximum voltage input is relevant.

AES-X168 Characterization of loudspeaker systems;
Scope: This document defines a set of characteristics of loudspeaker systems for inclusion in manufacturers’ specification documents, and identifies the relevant methods of measurement. It considers loudspeaker *systems* for professional applications. They may be combinations of active and passive sub-systems. It is intended for users and designers of loudspeaker system installations.

Status: Scope updated, writing has begun, first draft by David Murphy is posted to the repository.

Discussion: IEC 60268-22 is in development, and is monitored for content. After publication, expected in December 2020, work on X168 can begin.

Target: Draft standard fall 2022

AES-X241 AES Standard for Acoustics - End of Line Testing for Production Loudspeaker Drivers
Scope: This standard specifies parameters and methods of measurement required for end-of-line quality control tests performed on loudspeaker drivers manufactured for automotive, consumer and professional applications. It includes requirements for mechanical setup. It does not consider measurements of loudspeaker systems or multi-driver arrangements.

Status: The group is gathering comments on a draft. The next stage is to consider tolerances.

Discussion: Pietro Massini has updated the characteristics list spreadsheet to Google docs with updated comments received since the 148th.

AES-X250 AES Standard for Acoustics - Measuring maximum linear peak SPL using noise
Scope: This standard specifies a method for measuring the maximum linear peak SPL of a loudspeaker driver or system. It uses a mathematically derived test signal that effectively emulates the dynamic characteristics of music as a function of frequency as well as its spectral content. Status: Refining draft.

Discussion: Task group leaders Merlijn van Veen and Roger Schwenke are leading bi-weekly on-line meetings. Group has continued excellent progress developing the draft. Projected Draft goal is on track for late 2020.


Brian Vessa provided an overview of the SMPTE Cinema B-Chain as the audio segment of cinema sound reproduction comprising amplifiers, signal processing, loudspeakers and room equalization and calibration etc. The development of X250 to measure maximum linear SPL aligns well with SMPTE’s interest to evaluate cinema sound.

New Projects


New Business

There was no new business.

The next meeting will be scheduled in conjunction with the AES 150th Convention, to be held online in May 2021.

AES - Audio Engineering Society