Report of the meeting of the SC-04-03 Working Group on loudspeaker modeling and measurement of the SC-04 Subcommittee on Acoustics, held in New York, NY, 2018-10-17
The meeting was convened by chair S. Hutt.
Present were S Hutt, C Zhao, Y W Jiang, G Hill, B McLaughlin, A Voishvillo, B Kakonyi, J Buschitz, P Mapp, A Salvatti, C Struck, F Blasizzo, K Nagy, D Murphy, F Simon, J Britto, P Massini, W Klippel, S Thompson, D Blore, A Sobodnik, R Cabot.
Richard Cabot, the AES Standards Manager, read the AES patent policy statement.
The agenda and the report of the previous meeting, held in Milan, were approved as written.
The chair announced that David Murphy and Geoff Hill have volunteered to become vice-chairs of the working group.
AES-X223: Loudspeaker Driver Correlation Chamber: Information Document:
Scope:
Information document explaining factors affecting the interchangeability of measurement data from simple loudspeaker comparison chambers.
Status:
The current draft was updated to reflect absorption requirements and measurement uncertainty. A preliminary call for comment has been posted to the group document site. If no issues are found a formal call for comment will be issued before the end of the year.
Goal:
Call for Comment December 2018.
Release 2019.
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: A parameter list has been posted for comment, feedback requested. The next version of the draft will consider tolerances. Pietro Massini has developed a template, posted to the repository. Feedback is requested prior to next meeting at the 146th convention. Wolfgang Klippel proposed that we revisit the target with respect to total cost, realization difficulty and risk management.
Intent Target: Next draft 2019.
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:
The next revision, expected in 2020, will be approached as a total rewrite. Draft development is progressing. A key aspect is to clarify the definition of life testing and to find a satisfactory method of accelerated reliability testing. Power testing procedures have been discussed but there is still a divergence of opinion. The chair recognizes that further research is required to acquire data that can support the development of procedures. A detailed annex section will be required as an information document that supports the philosophy of the accelerated reliability testing, emphasizing that driver test values do not directly translate to system values used in every day situations.
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: Ed Simon recommended including a section on identifying the acoustic center.
Target: Draft fall 2019
AES-1id-R Review of AES-1id-2012: 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."
Status: The current version will be reaffirmed. The next revision is expected in 2022.
Liaisons:
W Klippel gave an overview of new work in IEC 60268-21 on loudspeaker drivers, IEC 60268-22 on loudspeaker systems, and IEC 63034 on micro-speakers.
John Busenitz reported that ALMA is working on a Hi2-Blat standard. When it is ready it could serve as a reference in AES-X241.
New Projects
There were no new projects.
New Business
There was no new business.
The next meeting will be scheduled in conjunction with the AES 146th Convention, to be held 20 to 23 March 2019 in Dublin, Ireland.
