SC-04-03 meeting report, Munich, 2009-09

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 Munich, Germany, 2009-05-08

Committee Scope: The scope of the SC-04-03 Working Group on Loudspeaker Modeling and Measurement includes the specification, modeling, and measurement of the electromechanical and free-field radiation characteristics of loudspeakers, individually and in arrays, intended for propagation of audio signals within the scope of SC-04.

The meeting was convened by chair S. Hutt, with vice-chair N. Harris.

The agenda and the report of the previous meeting, 2008-10-02, were accepted as written.

Open Projects

AES-1id-R: Review of AES-1id-1991 (r2003): Plane-Wave Tubes: Design and Practice
Project 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."

Assigned to: SC-04-03, Initiated: 2003
Intent: Revision, Target: 2008
Current goal: PTD, Goal date: 2007-10

Status: Secretariat-formatted draft submitted. Graph received from M. Buck. Discussion: Graph requires reformatting by secretariat.

AES-5id-R: Review of AES-5id-1997 (r2003): AES information document for Room acoustics and sound-reinforcement systems - Loudspeaker modeling and measurement - Frequency and angular resolution for measuring, presenting and predicting loudspeaker polar data
Project scope: This document provides guidelines for measuring, presenting, and predicting polar data from a single acoustic source or from an array of acoustic sources. It describes and quantifies possible errors, defined as differences in numeric values, associated with measurement resolution, presentation resolution, prediction techniques and measurement environments.

Assigned to: SC-04-03, Initiated: 2003-03
Intent: Review, Target: 2008
Current goal: Status report, Goal date: Continuing
Status: Proposal to be withdrawn upon release of AES56

AES2-R: Review of AES2-1984 (r2003): AES Recommended Practice - Specification of loudspeaker components used in professional audio and sound reinforcement
Project 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.

Assigned to: SC-04-03-A, Initiated: 2003
Intent: Revision, Target: 2007
Current goal: PTD, Goal date: 2007-07

Status: Part 1 approved for Call-For-Comment with email reflector revisions.

Discussion: The working group is congratulated on the completion of part 1. Part 1 will be used as a format reference for part 2.

A discussion on the scope of Part 2 ensued. The intent is to cover single, high-level input, passive systems, with a defined bandwidth, which may include enclosures or directivity-controlling devices. The scope discussion will continue over the reflector. The overall plan was reviewed:

  1. Drivers - Direct Radiators, Compression Drivers, and Driver-Waveguide combinations
  2. Systems - Passive
  3. Systems - Active (Passive systems with external, powered, electronic components)
  4. Systems - Powered (Systems with internal, powered, electronic components)
  5. added to cover systems of arrays (arrays of systems?)
  6. added for system evaluation in a room (car, hall)

J. Woodgate raised the concept that section 4 - "systems, powered" should be considered in the same light as section 2 - "systems, passive" citing that in essence a powered loudspeaker system is a black box with an approximately 10-kOhm input impedance vs. the passive loudspeaker having an approximately 4 or 8 ohm impedance.

Development Projects

AES-X129 : Loudspeaker Distortion Perception and Measurement
Project scope: to research the correlation of loudspeaker distortion perception with old and new distortion measures.

Assigned to: SC-04-03-D, Initiated: 2001-05 Intent: Information document, Target: 2008 Current goal: Status report, Goal date: 2007-10

Status: Continuing work in task group Discussion:

This work is required to complete other future projects.

Woodgate suggested that further work should be done at the AES Technical Committee level to gather and compile available literature. None of the attendees has been engaged with X129, however H. van Maanen volunteered to join the working group.

Liaisons:

No liaison discussion

New Projects:

No new projects.

New business:

There was no new business.

The next meeting will be scheduled in conjunction with the AES 127th Convention in New York, October 2009.

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