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AES Amsterdam 2008 Sunday, May 18, 14:00 — 16:00
Master Class Details
M1 - LOUDSPEAKER PARAMETERS
Richard Small, Harman-Motive Inc. - USA
Neville Thiele, University of Sydney - Sydney, NSW, Australia
The loudspeaker parameters provide a procedure that is now established universally for specifying loudspeaker drivers and designing their enclosures and associated equalizers. Their derivation and measurement involves simplifications and approximations to what is, in fact, a complex acoustical/mechanical/electrical system. They apply most accurately to the response of the system to small signals but nevertheless allow measurements to be made with surprisingly simple equipment and the performance of loudspeaker systems to be predicted with high precision. Since the initial publications between 1961 and 1973, their effectiveness has been increased through additions and refinements in understanding the mechanisms involved and in measuring and calculating them, made by a number of researchers and reported in a number of places. This master class aims to present them in a unified whole, correct some misconceptions, and answer some frequently-asked questions that, over the years, have arisen and mystified some students and designers.
Monday, May 19, 14:30 — 16:00
M2 - CONCEPTS IN SOUND QUALITY
Jens Blauert, Institute of Communication Acoustics - Bochum, Germany
The lecture presents a fundamental consideration of the nature of sound quality and offers ways for structuring different aspects of it. It aims at making audio engineers more aware of the various components and complex processes involved in the formation of sound-quality judgments. Thinking of sound quality means thinking of percepts, which brings subjectivity to the fore. To deal with subjectivity scientifically, the first part of the lecture will present a line of epistemological arguments that is stringently based on actual perception and not on fiction. In this way, the place and role of subjectivity in acoustics and audio engineering will be determined. To further elucidate the formation process of sound quality, the second part of the talk starts with the introduction of the character of sounds and then moves on to different aspects of sound quality , starting from sound quality (as such) through sound-transmission quality and auditory-scene quality to product-sound quality. A generalized, system-oriented approach toward sound-quality evaluation is thereupon presented. Finally, the third part of the talk deals exemplarily with sound quality in spaces for musical performances. The question of proper references turns out to be crucial for any further analysis. Consequently, efforts are taken to explore and assess these references systematically. To this end, a hierarchical order for references, based on the amount of abstraction, is proposed and discussed in some detail. Issues like typicalness, functional adequacy, aesthetic form, and tradition are touched upon.
Tuesday, May 20, 12:00 — 14:00
M3 - LINEAR AUDIO POWER AMPLIFICATION
Audio power amplifiers are one of the few fields where analog still has the upper hand when high quality is required. In this presentation I will review some of the configurations available and examine their advantages and otherwise. The classical amplifier configuration still remains extremely useful and is capable of very good results in terms of linearity when the design details are handled properly. I hope to show that this can be done easily. Some new findings in minimizing distortion will be presented. I shall also be looking at the issue of noise in power amplifier circuits, and how that too can be reduced as much as possible.
Tuesday, May 20, 14:30 — 16:30
M4 - A UNIVERSAL GRAMMAR OF CLASS D AUDIO AMPLIFICATION
Bruno Putzeys, Hypex Electronics and Grimm Audio - The Netherlands
At first sight, class D amplifiers exhibit a baffling array of disjoint design philosophies and topologies. Yet, all of these can be seen as permutations of the same basic structure. This Master Class explores the “universal grammar of class D audio amplification:" the building blocks and design choices underlying all class D designs, like power stage topology, loop control strategy, and modulation method. This generalized view makes clear how certain designs turn out to be uncontroversially suboptimal choices while some other apparently meaningless rearrangements like localized error feedback can be demonstrated to have real performance advantages.