2003 November, Volume 51 Number 11

CONTENT

President's Message
Ron Streicher   1011

PAPERS

The Effect of Nonlinear Distortion on Perceived Quality of Music and Speech Signals
Chin-Tuan Tan, Brian C. J. Moore, and Nick Zacharov   1012
The subjective evaluation of nonlinear distortions often shows a weak correlation with physical measures because the choice of distortion metrics is not obvious. In reexamining this subject, the authors validated a metric based on the change in the spectrum in a series of spectral bins, which when combined leads to a single distortion metric. Distortion was evaluated both objectively and subjectively using speech and music. Robust results support the hypothesis for this approach.

ENGINEERING REPORTS

Ultra-High Quality Video Frame Synchronous Audio Coding
Michael J. Smithers, Brett G. Crockett, and Louis D. Fielder   1032
When audio signals accompany video information, additional requirements are imposed on audio encoding to allow for frame-based video editing, switching, and splicing. Moreover within the bit budget, the number of channels and their bit allocation is flexible. In the proposed approach audio blocks are designed to match the frame boundaries, but with an additional transitional region that avoids time-domain aliases, a degradation resulting when neighboring blocks are no longer contiguous.

Large-Signal Analysis of Triode Vacuum-Tube Amplifiers
Muhammad Taher Abuelma'atti   1046
With the renewed interest in vacuum tubes, the issue of intrinsic distortion mechanisms becomes relevant again. The author demonstrates a nonlinear model of triodes and pentodes that leads to a closed-form solution when the nonlinearity is represented by a Fourier expansion rather than the conventional Taylor series. When applied to a two-tone sine wave, the analysis shows that the distortion in tube amplifiers is similar to that of the equivalent transistor amplifier. A SPICE analysis confirms the approach.

Acoustical Measurements of Traditional Theaters Integrated with Chinese Gardens
Weihwa Chiang, Yenkun Hsu, Jinjaw Tsai, Jiqing Wang, and Linping Xue   1054
The acoustics of three Chinese theaters from the nineteenth century were evaluated using the conventional metrics for performance spaces. Similar to the Western tradition, theaters evolved as one of three types: amphitheater, courtyard, and auditorium. However, Chinese theaters were often integrated with privately owned gardens with a diversified design and acoustic architecture. Even with a high degree of spatial irregularity, measurements were consistent with modern theater acoustics.

LETTERS TO THE EDITOR

Comments on "History of Spatial Coding"
Peter Scheiber   1063

Why Is Bass Reproduction from a Dipole Woofer in a Living Room Often Subjectively More Accurate Than from a Monopole Woofer?
Siegfried Linkwitz   1063

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   1064
Standards in print

FEATURES

Binaural Audio in the Era of Virtual Reality   1066
New Officers 2003/2004   1073
2003/2004 AES International Sections Directory   1078

DEPARTMENTS

News of the Sections   1104
Sound Track   1108
New Products and Developments   1108
Upcoming Meetings   1109
Available Literature   1110
Membership Information   1111
Advertiser Internet Directory   1112
AES Special Publications   1115
AES Conventions and Conferences   1120

FPO For the cover:

2003 November, Volume 51 Number 11

spine: 2003 November, Volume 51 Number 11