2001 March, Vol 49 Number 3

CONTENT

PAPERS

Development of the Two-Stage Harmonic Balance Method to Estimate Nonlinear Parameters of Electrodynamic Loudspeakers
Seok-Tae Park and Suk-Yoon Hong   99

A two-stage harmonic method is proposed to identify nonlinear parameters of loudspeakers. Estimated parameters describe the linear and nonlinear characteristics of a loudspeaker more accurately than previous, more conventional methods. This new method shows that stiffness nonlinearities are closely related to second-order harmonic distortion and intermodulation products of the diaphragm displacement, while the nonlinear damping coefficients are related to third-order harmonic and intermodulation products. This is potentially a helpful tool for improving loudspeaker design and performance.

On Sound Radiation from Ported Enclosures
Earl R. Geddes   117

The lumped-parameter models of Thiele and Small for designing vented loudspeaker boxes have become the defacto standard for their analysis and design. The author has shown that these lumped-parameter models have an implicit assumption which limits their accuracy. The presence of the limitations in these models is shown in a simple proof. A more accurate example of these limitations is demonstrated in the specific design of a ported enclosure in which a spherical enclosure model is used.

The Effects of Specular Versus Diffuse Reflections on the Frequency Response at the Listener
James A. S. Angus   125

The time evolution of sound energy and the reverberation in control rooms are important in the acoustical design of control and listening rooms. These rooms are frequently designed to achieve a large initial-time- delay gap between the direct sound from the loudspeakers and the first early reflections, which allows the sound engineers and producers to listen through the system to the acoustic space being recorded. This is accomplished in a variety of ways based on absorption, specially shaped walls, and diffusion.

Sound Composition with Pulsars
Curtis Roads   134

A method of electronic music synthesis based on the generation of trains of sonic particles has been called pulsar synthesis (PS). Pulsar synthesis can produce either rhythms or tones and generates sounds similar to vintage electronic music sonorities with several important enhancements. The author along with Alberto Campo has designed a program for pulsar synthesis called PulsarGenerator.

STANDARDS AND INFORMATION DOCUMENTS

AES-4id-2001 AES information document for room acoustics and sound reinforcement systems - Characterization and measurement of surface scattering uniformity   148

AES Standards Committee News   166
Amsterdam meetings; forensic audio; multiple contact connectors

Call for Comment on DRAFT REVISED AES-3id-xxxx, AES information document for digital audio engineering -- Transmission of AES3 formatted data by unbalanced coaxial cable   166

Call for Comment on DRAFT AES45-xxxx, AES standard for single-programme connectors -- Connectors for loudspeaker-level patch panels   166

FEATURES

110th Convention Preview, Amsterdam   170
     Calendar   172
     Exhibitors   174
     Exhibitor Previews   178

Updates and Corrections to the 2000/2001 International Sections Directory   191

DEPARTMENTS

News of the Sections   192

Upcoming Meetings   196

Sound Track   197

Available Literature   198

Membership Information   199

Advertiser Internet Directory   202

In Memoriam   204

AES Special Publications   205

Sections Contacts Directory   210

AES Conventions and Conferences   216

FPO For the cover:

2001 March, Vol 49 Number 3

spine: 2001 March, Vol 49 Number 3