AES London 2010
Poster Session P6

Saturday, May 22, 14:00 — 15:30 (Room C4-Foyer)

P6 - Audio Equipment and Emerging Technologies

P6-1 Study and Evaluation of MOSFET Rds_(ON) Impedance Efficiency Losses in High Power Multilevel DCI-NPC Amplifiers—Vicent Sala, G. Ruiz, Luis Romeral, UPC-Universitat Politecnca de Catalunya - Terrassa, Spain
This paper justifies the usefulness of multilevel power amplifiers with DCI-NPC (Diode Clamped Inverter – Neutral Point Converter) topology in applications where size and weight needs were optimized. These amplifiers can work at high frequencies thereby reducing the size and weight of the filter elements. However, it is necessary to study, analyze, and evaluate the efficiency losses because this amplifier has double the number of switching elements. This paper models the behavior of the MOSFET Rds_(ON) in a DCI-NPC topology for different conditions.
Convention Paper 7996 (Purchase now)

P6-2 Modeling Distortion Effects in Class-D Amplifier Filter Inductors—Arnold Knott, Tore Stegenborg-Andersen, Ole C. Thomsen, Technical University of Denmark - Lyngby, Denmark; Dominik Bortis, Johann W. Kolar, Swiss Federal Institute of Technology in Zurich - Zurich, Switzerland; Gerhard Pfaffinger, Harman/Becker Automotive Systems GmbH - Straubing, Germany; Michael A. E. Andersen, Technical University of Denmark - Lyngby, Denmark
Distortion is generally accepted as a quantifier to judge the quality of audio power amplifiers. In switch-mode power amplifiers various mechanisms influence this performance measure. After giving an overview of those, this paper focuses on the particular effect of the nonlinearity of the output filter components on the audio performance. While the physical reasons for both, the capacitor and the inductor induced distortion are given, the practical in-depth demonstration is done for the inductor only. This includes measuring the inductors performance, modeling through fitting and resulting into simulation models. The fitted models achieve distortion values between 0.03 % and 0.20 % as a basis to enable the design of a 200 W amplifier.
Convention Paper 7997 (Purchase now)

P6-3 Multilevel DCI-NPC Power Amplifier High-Frequency Distortion Analysis through Parasitic Inductance Dynamic Model—Vicent Sala, G. Ruiz, E. López, Luis Romeral, UPC-Universitat Politecnica de Catalunya - Terrassa, Spain
The high frequency distortion sources in DCI-NPC (Diode Clamped Inverter- Neutral Point Converter) amplifiers topology are studied and analyzed. It has justified the need for designing a model that contains the different parasitic inductive circuits that presents dynamically this kind of amplifier, as a function of the combination of its active transistors. By means of a proposed pattern layout we present a dynamic model of the parasitic inductances of the amplifier Full-Bridge DCI-NPC, and this is used to propose some simple rules for the optimal designing of layouts for these types of amplifiers. Simulation and experimental results are presented to justify the proposed model, and the affirmations and recommendations are given in this paper.
Convention Paper 7998 (Purchase now)

P6-4 How Much Gain Should a Professional Microphone Preamplifier Have?—Douglas McKinnie, Middle Tennessee State University - Murfreesboro, TN, USA
Many tradeoffs are required in the design of microphone preamplifier circuits. Characteristics such as noise figure, stability, bandwidth, and complexity may be dependent upon the gain of the design. Three factors determine the gain required from a microphone preamp: sound-pressure level of the sound source, distance of the microphone from that sound source (within the critical distance), and sensitivity of the microphone. This paper is an effort to find a probability distribution of the gain settings used with professional microphones. This is done by finding the distribution of max SPL in real use and by finding the sensitivity of the most commonly used current and classic microphones.
Convention Paper 7999 (Purchase now)

P6-5 Equalizing Force Contributions in Transducers with Partitioned Electrode—Libor Husník, Czech Technical University in Prague - Prague, Czech Republic
A partitioned electrode in an electrostatic transducer can present among others a possibility for making the transducer with the direct D/A conversion. Nevertheless, partitioned electrodes, the sizes of which are proportional to powers of 2 or terms of other convenient series, do not have the corresponding force action on the membrane. The reason is the membrane does not vibrate in a piston-like mode and electrode parts close to the membrane periphery do not excite membrane vibrations in the same way as the elements near the center. The aim of this paper is to suggest equalization of force contributions from different partitioned electrodes by varying their sizes. Principles presented here can also be used for other membrane-electrode arrangements.
Convention Paper 8000 (Purchase now)

P6-6 Low-End Device to Convert EEG Waves to MIDI—Adrian Attard Trevisan, St. Martins Institute of Information Technology - Hamrun, Malta; Lewis Jones, London Metropolitan University - London, UK
This research provides a simple and portable system that is able to generate MIDI output based on the inputted data collected through an EEG collecting device. The context is beneficial in many ways, where the therapeutic effects of listening to the music created by the brain waves documents many cases of treating health problems. The approach is influenced by the interface described in the article “Brain-Computer Music Interface for Composition and Performance” by Eduardo Reck Miranda, where different frequency bands trigger corresponding piano notes through, and the complexity of, the signal represents the tempo of the sound. The correspondence of the sound and the notes have been established through experimental work, where data of participants of a test group were gathered and analyzed, putting intervals for brain frequencies for different notes. The study is an active contribution to the field of the neurofeedback, by providing criteria tools for assessment.
Convention Paper 8001 (Purchase now)

P6-7 Implementation and Development of Interfaces for Music Performance through Analysis of Improvised Dance Movements—Richard Hoadley, Anglia Ruskin University - Cambridge, UK
Electronic music, even when designed to be interactive, can lack performance interest and is frequently musically unsophisticated. This is unfortunate because there are many aspects of electronic music that can be interesting, elegant, demonstrative, and musically informative. The use of dancers to interact with prototypical interfaces comprising clusters of sensors generating music algorithmically provides a method of investigating human actions in this environment. This is achieved through collaborative work involving software and hardware designers, composers, sculptors, and choreographers who examine aesthetically and practically the interstices of these disciplines. This paper investigates these interstices.
Convention Paper 8002 (Purchase now)

P6-8 Violence Prediction through Emotional Speech—José Higueras-Soler, Roberto Gil-Pita, Enrique Alexandre, Manuel Rosa-Zurera, Universidad de Alcalá - Acalá d Henares, Madrid, Spain
Preventing violence takes an absolute necessity in our society. Whether in homes with a particular risk of domestic violence, as in prisons or schools, there is a need for systems capable of detecting risk situations, for preventive purposes. One of the most important factors that precede a violent situation is an emotional state of anger. In this paper we discuss the features that are required to provide decision makers dedicated to the detection of emotional states of anger from speech signals. For this purpose, we present a set of experiments and results with the aim of studying the combination of features extracted from the literature and their effects over the detection performance (relationship between probability of detection of anger and probability of false alarm) of a neural network and a least-square linear detector.
Convention Paper 8003 (Purchase now)

P6-9 FoleySonic: Placing Sounds on a Timeline through Gestures—David Black, Kristian Gohlke, University of Applied Sciences, Bremen - Bremen, Germany; Jörn Loviscach, University of Applied Sciences, Bielefeld - Bielefeld, Germany
The task of sound placement on video timelines is usually a time-consuming process that requires the sound designer or foley artist to carefully calibrate the position and length of each sound sample. For novice and home video producers, friendlier and more entertaining input methods are needed. We demonstrate a novel approach that harnesses the motion-sensing capabilities of readily available input devices, such as the Nintendo Wii Remote or modern smart phones, to provide intuitive and fluid arrangement of samples on a timeline. Users can watch a video while simultaneously adding sound effects, providing a near real-time workflow. The system leverages the user’s motor skills for enhanced expressiveness and provides a satisfying experience while accelerating the process.
Convention Paper 8004 (Purchase now)

P6-10 A Computer-Aided Audio Effect Setup Procedure for Untrained Users—Sebastian Heise, Michael Hlatky, Hochschle Bremen (University of Applied Sciences) - Bremen, Germany; Jörn Loviscach, Fachhochschule Bielefeld (University of Applied Sciences) - Bielefeld, Germany
The number of parameters of modern audio effects easily ranges in the dozens. Expert knowledge is required to understand which parameter change results in a desired effect. Yet, such sound processors are also making their way into consumer products, where they overburden most users. Hence, we propose a procedure to achieve a desired effect without technical expertise based on a black-box genetic optimization strategy: Users are only confronted with a series of comparisons of two processed examples. Learning from the users’ choices, our software optimizes the parameter settings. We conducted a study on hearing-impaired persons without expert knowledge, who used the system to adjust a third-octave equalizer and a multiband compressor to improve the intelligibility of a TV set.
Convention Paper 8005 (Purchase now)