SC-04-03 meeting, Online, 2022-05

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, 2022-05-02.

The meeting was convened by chair G. Hill.

Present were Patrick Neville, Dennis Walsh, Charlie Hughes, David Krix, Geoff Hill, Thomas Gmeiner, Daniele Ponteggia, Roger Schwenke, Merlijn van Veen, Gerhard Elvina, David Bialik, Bruce Olson, Jim Meyer, David Prince, Steve Hutt, Neil Shaw, Alex Voishvillo, Tim Gladwin, Brian Vessa, JP Axelsson, Richard Cabot.

The formal notice on patent policy was read.

The agenda and the report of the previous meeting, held in online, 2021-10-07, were approved as written.

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

Open projects

AES1id-R Review of AES-1id-2012 (r2017): AES Information Document for Acoustics - Plane-Wave Tubes - Design and Practice
Scope: To establish, expand, and improve the practice for the design and use of plane-wave tube measurement techniques, as recommended in section 2.2.1 of AES2-1984, "Recommended Practice Specification of Loudspeaker Components Used in Professional Audio and Sound Reinforcement."

Intent: Review, Target: 2022

Discussion: David Murphy has drafted an informative annex on how to use impulse responses to adjust for minimum reflections he is asked to send this to the secretariat for inclusion for consideration at the next meeting. Need a volunteer to lead review of the current document.

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, target 2023

Discussion: : With AES standard AES75 now issued and both IEC 60268-21 and IEC 60268-22 all formally published the question was asked if AES2 should now be updated and how? After discussion David Prince agreed to coordinate efforts and to report back at next meeting.

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, a first draft by David Murphy is posted to the repository.

Discussion: IEC documents relative to development AEX-x168 are published and available for task group review. IEC: 60268-21 - “Sound system equipment - Part 21: Acoustical (Output based) measurements and” and IEC:60268-22 “Sound system equipment - Part 22: Electrical and mechanical measurements on transducers”. The question being asked to what extent should this and other documents refer to the published IEC documents?.

Drafts available for review: john Woodgate and David Murphy drafts are available; members are asked to review these documents for the next meeting.

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.

Changing intent from Standard to Information Document. Changing target to 2022/10.

Discussion: Basically bogged down – vehicle manufacturers want this but won’t contribute and tier 1 follow the vehicle manufacturer David Prince commented a similar requirement and would be prepared to lead in revising scope, and anyone else who is interested please get involved..

It was suggested that an end-of-line test procedure for manufacturing loudspeaker drivers may also be of use for quality management for incoming QC, or ongoing QC, for example in the pro-audio segment.

We need volunteers to move this project forward.

AES75 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: Document is now a published standard.

Discussion: – How do we get the industry to use it? There is a place on the website to promote AES67 so yes we are interested in promoting any of our Standards / Information documents generally – we should generate an appropriate Task Force – send suggestions to the Standards Manager at [email protected].

Could we use 04-03a task group for this? Bruce Olsen confirmed that it was appropriate for this to happen, the scope of the task group should be updated, but requested that an e-mail be sent from the 04-03a reflector to give people the option of Opt-in or to Opt-out and withdrawing from this task group if they were not interested in the updated scope.



New Projects

Head Acoustics – MOS score using Loudspeakers should we be involved?

New Business

Two People, Geoff Hill and Charlie Hughes have expressed and interest in chairing the group, anyone else who is interested please e-mail the Standards Manager at [email protected]

The next meeting will be scheduled in conjunction with the AES 153nd Convention, to be held in October 2022.

AES - Audio Engineering Society