AES Budapest 2012
Saturday, April 28, 15:30 — 17:00 (Room: Foyer)
1 An Exact Harmonic Computing Technique for Polynomial Nonlinearities—Nay Oo, Fraunhofer Institute for Digital Media Technology, IDMT - Oldenburg, Germany; Woon-Seng Gan, Nanyang Technology University - Singapore, Singapore
An exact harmonic computing technique for polynomial nonlinearities is developed from first principles. By applying this technique, when an input sinusoid with arbitrary amplitude, frequency and phase information and a polynomial nonlinearity are given, the exact computation of DC component and output harmonics’ amplitudes, frequencies, and phases is computationally possible without discrete Fourier transform (DFT). Two basic mathematical results such as power of cosine and harmonic addition theorem are utilized to develop this technique.
Engineering Brief 47 (Download now)
2 Suspension Creep Models for Miniature Loudspeakers—Holger Hiebel, Knowles Electronics Austria GmbH - Vienna, Austria, Graz University of Technology, Graz, Austria
Different models for describing the suspension creep behavior of loudspeakers are available at the moment. They include the “LOG”-model from Knudsen, the model used in the Klippel Analyzer system (same as Knudsen, but neglecting the frequency dependent losses) and the 3-parameter model of Ritter and Agerkvist. In contrast to HiFi speakers the differences between the creep models can be seen more clearly in miniature loudspeakers using compound (multilayer) membranes. Benefits from choosing the right creep model are tabulated in terms of RMS fit errors and evaluation results for miniature loudspeaker samples are shown.
Engineering Brief 48 (Download now)
3 Smart Microphone Sensor System Platform—Elias Kokkinis, University of Patras - Patras, Greece; Konstantinos Drossos, Ionian University - Corfu, Greece; Nicolas-Alexander Tatlas, BLUEdev Ltd. - Patras, Greece; Andreas Floros, Ionian University - Corfu, Greece; Alexandros Tsilfidis, University of Patras - Patras, Greece; Kyriakos Agavanakis, BLUEdev Ltd. - Patras, Greece
A platform for a flexible, smart microphone system using available hardware components is presented. Three subsystems are employed, specifically: (a) a set of digital MEMs microphones, with a one-bit serial output; (b) a preprocessing/digital-to-digital converter; and (c) a CPU/DSP-based embedded system with I2S connectivity. Basic preprocessing functions, such as noise gating and filtering can be performed in the preprocessing stage, while application-specific algorithms such as word spotting, beam-forming, and reverberation suppression can be handled by the embedded system. Widely used high-level operating systems are supported including drivers for a number of peripheral devices. Finally, an employment scenario for a wireless home automation speech activated front-end sensor system using the platform is analyzed.
Engineering Brief 49 (Download now)
4 Sound Field Synthesis Toolbox—Hagen Wierstorf, Sascha Spors, TU Berlin - Berlin, Germany
An open source toolbox for Sound Field Synthesis (SFS) is introduced. The toolbox is able to numerically simulate sound fields synthesized by SFS methods like Wave Field Synthesis or higher order Ambisonics. Various loudspeaker driving signals for the mentioned methods are provided for 2-, 2.5-, and 3-dimensional synthesis. The toolbox allows mono-frequent as well as broadband excitation signals. The latter allows generation of snapshots of the spatio-temporal impulse response of a chosen reproduction technique. The toolbox furthermore includes the computation of binaural room impulse responses (BRIR) for a given SFS setup. These can be used to simulate different sound field synthesis methods via binaural resynthesis.
The toolbox is provided for Matlab/Octave and comes with an online documentation.
Engineering Brief 50 (Download now)
5 Listening to the Large Hadron Collider—Daniel Deboy, CERN - Geneva, Switzerland, University of Music and Performing Arts, Graz, Austria; Ralph W. Aßmann, Roderik Bruce, Florian Burkart, Marija Cauchi, Clement Derrez, Alessandro Masi, Stefano Redaelli, Belen Salvachua, Gianluca Valentino, Daniel Wollmann, CERN - Geneva, Switzerland
The Large Hadron Collider (LHC) at CERN is a high-energy particle accelerator in a 27 km long tunnel located in the underground of the Geneva area, Switzerland. Protons are accelerated to 99.9999991 percent of the speed of light before they collide with a total momentum of up to 14 TeV. It is the largest machine that human mankind has ever built. Over 10.000 sensors monitor the state of the LHC during operation. Recently, microphones have been added as an experimental setup. An acoustic monitoring system to detect and localize beam accidents is under current investigation. Such a system may reduce expensive downtime dramatically in an accident scenario. The acquired signals can also be used for other applications, e.g., sonification, media art installations, etc.
Engineering Brief 51 (Download now)
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