AES Berlin 2014
Poster Session P9

P9 - Audio Signal Processing/Transducers/Recording/Network Audio

Monday, April 28, 15:00 — 16:30 (Foyer)

P9-1 Adaptive Digital Oscillator for Virtual Acoustic FeedbackLeonardo Gabrielli, Universitá Politecnica delle Marche - Ancona, Italy; Marco Giobbi, Universita Politecnica delle Marche - Ancona, Italy; Stefano Squartini, Università Politecnica delle Marche - Ancona, Italy; Vesa Välimäki, Aalto University - Espoo, Finland
In the domain of Virtual Acoustics research, the emulation of acoustic feedback, such as the so-called guitar howling, has been scarcely addressed. This paper takes pace from this peculiar effect to introduce a computational technique aimed at its emulation and extension to possible new scenarios of Virtual Acoustics. A nonlinear digital oscillator for real-time operation with good stability properties and low computational cost is employed to emulate guitar feedback (or guitar howling). The oscillator frequency is tuned according to a pitch detection system that adaptively tracks pitch changes in real-time. A real-time implementation of the algorithm in the Puredata environment has been developed to provide guitar howling emulation.
Convention Paper 9066 (Purchase now)

P9-2 A Psychoacoustic-based Vocal Suppression for Enhanced Interactive Service Using Spatial Audio Object CodingTung Chin Lee, Yonsei University - Seoul, Korea; Young-cheol Park, Yonsei University - Wonju, Kwangwon-do, Korea; Dae Hee Youn, Yonsei University - Seoul, Korea
In this paper we present a new vocal suppression algorithm that can enhance the quality of music signal coded using Spatial Audio Object Coding (SAOC) in Karaoke mode. The remained vocal component in the coded music signal is estimated and suppressed by using a spectral subtraction method. Using the fact that the level of the remained vocal components is varied depending on the input object power, we propose a psychoacoustic rule where the suppression level is adapted according to the auditory masking property. Objective and subjective test were performed and the results confirm that the proposed algorithm offers an improved quality.
Convention Paper 9067 (Purchase now)

P9-3 Application of Common-Pole Parallel Filters to Nonlinear Models Based on Orthogonal FunctionsLaura Romoli, Universitá Politecnica della Marche - Ancona, Italy; Stefania Cecchi, Universitá Politecnica della Marche - Ancona, Italy; Balázs Bank, Budapest University of Technology and Economics - Budapest, Hungary; Michele Gasparini, Universitá Politecnica della Marche - Ancona, Italy; Francesco Piazza, Universitá Politecnica della Marche - Ancona (AN), Italy
Different nonlinear models are exploited to model real-world devices. Among them, an effective technique is based on the combination of orthogonal nonlinear functions and frequency-domain adaptive filtering algorithms for nonlinear system identification. In this paper first the independence of the model from the orthogonal basis is demonstrated by complementing previously obtained results. Then, a highly efficient model implementation is presented by taking advantage of fixed pole parallel filters for the linear filtering part. The efficiency comes both from using common-pole modeling and from applying a warped filter design that takes into account the frequency resolution of human hearing. Experimental results prove the effectiveness of the proposed approach showing its suitability in real-time digital simulation of nonlinear audio devices.
Convention Paper 9068 (Purchase now)

P9-4 Multiphysic Modeling and Heuristic Optimization of Compression Driver DesignMichele Gasparini, Universitá Politecnica della Marche - Ancona, Italy; Stefania Cecchi, Universitá Politecnica della Marche - Ancona, Italy; Francesco Piazza, Universitá Politecnica della Marche - Ancona (AN), Italy; Emiliano Capucci, Faital S.P.A. - Milan, Italy; Romolo Toppi, Faital S.P.A. - Milan, Italy
The use of finite element analysis is quite common in modern design techniques. Modeling allows to save time and efforts, especially when complex phenomena have to be considered. A compression driver is an example of a product with a problematic design, because the great number of variables and the different physics that are involved in the sound generation process makes the direct solution of mathematical models not trivial. In this paper an algorithm that optimizes the design parameters of the driver through an evolution strategies based procedure, taking advantage of the accuracy of the results from finite elements simulation, is presented. The method has been tested by optimizing a real compression driver and the results are reported.
Convention Paper 9069 (Purchase now)

P9-5 Properties of Gradient LoudspeakersSigmund Gudvangen, Buskerud and Vestfold University College - Kongsberg, Norway
The radiation pattern of loudspeakers play a crucial role for how the acoustic power is distributed in the room. There is mounting evidence that early reflections from the side walls are beneficial, while early reflections parallel to the sagittal plane appears to be less desirable. Gradient loudspeakers provide a means of producing unidirectional radiation patterns. Moreover, their radiation patterns are frequency-independent. In view of these very desirable properties the characteristics of first-order gradient loudspeakers are analyzed. General expressions for sound pressure and particle velocity are derived and the distortion of the radiation patterns in the high-frequency region is reviewed.
Convention Paper 9070 (Purchase now)

P9-6 A Guide to the Design and Evaluation of New User Interfaces for the Audio IndustryChristopher Dewey, University of Huddersfield - Huddersfield, UK; Jonathan Wakefield, University of Huddersfield - Huddersfield, UK
This paper starts from the viewpoint that the audio industry should take advantage of the possibilities offered by new visual and interactive interfaces in order to provide the best tools for audio tasks. Audio industry products have moved toward better displays in modern digital mixers and digital audio workstations but haven’t fully embraced the possibilities of current interface technology and remain largely traditional in interface design. In order for audio engineers to develop new visual and interactive audio products an understanding of existing Human Computer Interface (HCI) design and evaluation methodology is required. This paper presents a design and evaluation process that is tailored to audio industry product development and was used in developing a new EQ interface.
Convention Paper 9071 (Purchase now)

P9-7 An Open-Source Dynamic Networked Audio SystemMichelle Daniels, University of California San Diego - La Jolla, CA, USA
This paper presents an open-source networked audio system for managed networks that consists of a single Streaming Audio Manager (SAM) and an arbitrary number of clients that can be dynamically added to or removed from the system. Clients stream multichannel uncompressed audio to SAM using the Real-Time Transport Protocol. Inside of SAM, clients can be muted and soloed, and their volume can be adjusted. Additionally, client streams can be delayed to compensate for static differences in latency between audio and video playback in a multimedia environment. Basic SAM setups mix all incoming streams to a specified set of output channels. However, in advanced setups, SAM can send discrete outputs for each client to an external audio rendering system, which communicates with SAM using Open Sound Control (OSC). Third party developers can create their own renderers for advanced audio processing and can also implement user interfaces to remotely control and monitor SAM and its clients using additional OSC messages.
Convention Paper 9072 (Purchase now)

Return to Paper Sessions

EXHIBITION HOURS April 26th   10:00 - 18:30 April 27th   09:00 - 18:30 April 28th   09:00 - 18:30 April 29th   09:00 - 14:00
REGISTRATION DESK April 26th   09:30 - 18:30 April 27th   08:30 - 18:30 April 28th   08:30 - 18:30 April 29th   08:30 - 16:30
TECHNICAL PROGRAM April 26th   10:00 - 18:00 April 27th   09:00 - 18:00 April 28th   09:00 - 18:00 April 29th   09:00 - 17:00
AES - Audio Engineering Society