1998 May, VOLUME 46 NUMBER 5

CONTENT

PAPERS

The "Stereo Dipole"-A Virtual Source Imaging System Using Two Closely Spaced Loudspeakers
Ole Kirkeby, Philip A. Nelson, and Hareo Hamada 387
Two closely spaced dipole loudspeakers can create convincing virtual acoustical images in front of a single listener using a novel system. The proposed arrangement is robust with regard to the listener's head movements and the required signal processing is free of excessive artifacts. An unexpected characteristic of this scheme is that closely spaced loudspeaker configurations produce more accurate imaging than those in which the loudspeakers are more widely spaced.

Relationships among Measures of Speech Intelligibility in Rooms
J. S. Bradley 396
Speech intelligibility in rooms is related to both the signal-to-noise ratio and to the acoustical characteristics of the space, each of which can be evaluated separately. Modern measurement techniques are now used to assess the influence of rooms on speech intelligibility by quantifying early-to-late arrival sound ratios and the speech transmission index.

Linear-Phase Crossover Design Using Digital IIR Filters
P. Reviriego, José Parera, and R. García 406
Where linear-phase response is important, a procedure to design linear-phase all-pass two-way crossover systems using digital IIR filters is presented. It is shown that these linear-phase crossover filter designs exhibit good off-axis response for noncoincident aligned drivers while exhibiting low phase distortion.

ENGINEERING REPORTS

Music Signal Segmentation Using Tree-Structured Filter Banks
Miljko Bobrek and Daniel B. Koch 413
An 11-stage tree-structured filter bank is described that uses wavelet packet analysis. This novel filter bank is applied to music signal segmentation. Over a wide range of frequencies the filter bank has sufficient frequency resolution for the human ear, and the high-frequency time resolution is equally aurally effective. A new family of quadrature mirror filters with a narrow transition region and a low reconstruction error was implemented to improve selectivity.

STANDARDS AND INFORMATION DOCUMENTS

AES17-1998 AES standard method for digital audio engineering - Measurement of digital audio equipment 428

AES Standards Committee News 448

Digital interfaces; preservation of mechanical records; connectors; file exchange; AES-24

FEATURES

The Compact Disc Story
Kees A. Schouhamer Immink 458

Audio on Data Networks
Francis Rumsey 466

AES Goes Gold
Abbie Cohen 470

1998 Directory of Educational Programs (insert)

DEPARTMENTS
Review of Acoustical Patents 453
News of the Sections 472
Sound Track 474
Upcoming Meetings 476
New Products and Developments 476
Available Literature 479
Membership Information 481
In Memoriam 486
Audio Engineering Society Application Instructions 488
Sections Contacts Directory 491
AES Conventions and Conferences 496