2004 November, Volume 52 Number 11

CONTENT

President's Message
Theresa Leonard   1123

PAPERS

Dithered Noise Shapers and Recursive Digital Filters
Stanley P. Lipshitz, Robert A. Wannamaker, and John Vanderkooy   1124
Quantizers combining the use of colored, nonsubtractive dither with or without noise-shaping error feedback are closely examined for the first time. In particular, it is shown that the appropriate use of spectrally shaped dither signals entails subtle practical and theoretical considerations, especially if such dithers are combined with noise-shaping schemes. A rigorous analysis of systems employing such dither signals with and without feedback is undertaken, yielding practical guidelines that ensure satisfactory results in applications. In particular, it is shown that the class of dither signals suitable for combination with noise shaping is greatly restricted.

Motion-Tracked Binaural Sound
V. Ralph Algazi, Richard O. Duda, and Dennis M. Thompson   1142
By using a head tracking system that selects from an array of microphones placed on a surface that approximates the listener's head, the authors have created an alternative to the conventional binaural recording technique. Based on the orientation of the listener, the appropriate microphone is selected or the signals from a pair of microphone signals are interpolated. Head tracking provides strong dynamic cues that create a strong sense of realism with a reduced need for pinna matching. This approach supports multiple listeners from a single microphone array.

Importance and Representation of Phase in the Sinusoidal Model
Tue Haste Andersen and Kristoffer Jensen   1157
While the importance of differential phase among the components of an audio signal has been debated over the years, experiments show that both synthesized and encoded audio need to consider phase integrity. Subjective listening tests with sounds that were synthesized with varying amounts of phase information clearly demonstrate the need to use a reliable phase model, especially with common harmonic musical sounds. A novel phase representation, called partial-period phase, characterizes phase evolution as an almost stationary parameter.

ENGINEERING REPORTS

Direct Approximate Third-Order Response Synthesis of Vented-Box Loudspeaker Systems
Bernat Llamazares   1170
Discussions about subjective loudspeaker preferences often ignore the need for a rating scale to evaluate accuracy. Preferences and accuracy are different perceptual qualities. Accuracy relates to the degree to which a reproduced sound field is subjectively equivalent to a corresponding live presentation of the same source. There is no proof that preferences among different individuals will match accuracy.

CORRECTIONS

Correction to "Analysis of Loudspeaker Line Arrays"
Mark S. Ureda   1176

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   1177
Synchronization; optical disks; media storage; file interchange; jitter

FEATURES

Metadata Revisited: Six New Things to Know About Audio Metadata   1178
Digital Archive Strategies and Solutions for Radio Broadcasting   1180
New Officers 2004/2005   1185
26th Conference, Denver, Call for Papers   1200

DEPARTMENTS

News of the Sections   1188
Upcoming Meetings   1192
Sound Track   1192
New Products and Developments   1193
Available Literature   1194
Membership Information   1195
Advertiser Internet Directory   1197
Sections Contacts Directory   1201
AES Conventions and Conferences   1208

FPO For the cover:

2004 November, Volume 52 Number 11

spine: 2004 November, Volume 52 Number 11