|Subtractive and Nonsubstractive Dithering: A Mathematical Comparison (PDF-303KB)
|Robert A. Wannamaker
|The relative advantages and disadvantages of subtractive and nonsubtractive dithering are explored from a mathematical perspective. Subtractively dithered systems can yield quantization errors that are statistically independent of the input signal, but that require the dither signal be either transmitted or reconstructed at the receiver. In contrast, nonsubtractively dithered systems avoid this drawback but increase the level of noise at the output and can only render a specified number of statistical error moments independent of the system input. Nonetheless, appropriately chosen nonsubtractive dither signals prove suitable for audio and many other applications. The treatment presented extends to include new results regarding the use of spectrally colored dither signals in systems with and without noise-shaping error feedback.
|Measuring and Predicting the Perceived Quality of Music and Speech Subjected to Combined Linear and Nonlinear Distortion (PDF-355KB)
|Brian C. J. Moore, Chin-Tuan Tan, Nick Zacharov, and Ville-Veikko Mattila
|A new model is presented for predicting the perceived quality of audio signals subjected to both linear and nonlinear distortion. Earlier research produced metrics for predicting the effects of linear distortion (frequency response irregularity) and nonlinear distortion (production of spurious spectral components). The new model, which includes both metrics, provides predictions that correlate highly with results of subjective tests: correlations were 0.90 for music and 0.85 for speech.
|Circular Recital Hall Design Considering Source Directivity (PDF-594KB)
|Wei-Hwa Chiang, Yi-Nuo Chao, Jow-Yeh Lee, and Hui-Ping Wu
|During the remodeling of the Carrie Chang Music Hall, early reflections were incorporated into the acoustical design in order to compensate for the loss of high frequencies in those seats that were off axis. The design concentrated on several issues: changes in tone quality resulting from source directivity, sound focusing from curved surfaces, and coloration due to discrete early reflections. Computer and scale models allowed for acoustic analysis during successive design phases.
|Study of the Directional Characteristics of a Piston Mounted on a Surface of Zero Acoustic Impedance (PDF-369KB)
|José Luis Barros, Jorge Cárdenas, and Jorge Sommerhoff
|The surface impedance of a loudspeaker baffle strongly influences the directionality of the radiation pattern. By contrasting the radiation pattern of a vibrating piston mounted in a surface having infinite impedance with one having zero impedance, the importance of surface impedance is clearly demonstrated. Because energy cannot flow horizontally in a zero impedance surface, energy is concentrated in the axial direction. A two-dimensional model produced results that were consistent with those measured in the laboratory.
|LETTERS TO THE EDITOR
|Comments on "Coding for High-Resolution Audio Systems"
|David Moran, Roy Allison, and E. Brad Meyer (PDF-92KB)
|David Hadaway (PDF-92KB)
|J. Robert Stuart (PDF-92KB)
|STANDARDS AND INFORMATION DOCUMENTS
|Special Feature: Real-World Applications of ATM Networking for Professional Audio Using the AES47 Standard (PDF-602KB)
|The World of Digital Radio (PDF-1.4MB)
|Call for Nominations for Board of Governors (PDF-78KB)
|Call for Awards Nominations (PDF-80KB)
|12th Regional Convention, Tokyo, Call for Papers (PDF-97KB)
|27th Conference, Copenhagen, Call for Papers (PDF-86KB)
|Bylaws: Audio Engineering Society, Inc. (PDF-100KB)
|Index to Volume 52 (PDF-173KB)
|Reviews of Acoustical Patents (PDF-170KB)
|News of the Sections (PDF-384KB)
|Sound Track (PDF-161KB)
|New Products and Developments (PDF-118KB)
|Available Literature (PDF-122KB)
|Upcoming Meetings (PDF-122KB)
|Membership Information (PDF-135KB)
|Advertiser Internet Directory (PDF-108KB)
|In Memoriam (PDF-152KB)
|Sections Contacts Directory (PDF-135KB)
|AES Conventions and Conferences (PDF-191KB)
|Cover & Sustaining Members List (PDF-130KB)
|VIP List & Editorial Staff (PDF-100KB)