AES London 2011
Engineering Brief EB2

EB2 - Engineering Tools and Methods

Sunday, May 15, 16:00 — 17:30 (Room: Foyer)

EB2-1 Creative Abuse in Time StretchingJustin Paterson, University of West London
An area of digital audio manipulation currently in flux is that of time stretching. Following the emergence of real-time granular synthesis as a compositional tool, early sampler-based implementations were pushed beyond "authenticity" to create new timbres in the commercial music of the 1990s. As the algorithms improve, allowing more flexible and transparent implementation today, even more opportunities for a new "creative abuse" exist. This brief will first contextualize through consideration of the metaphor of authenticity in the tape recording of the 1940s and its soon-parallel abuse, which offered new pathways into multi-tracking and Musique Concrète. The brief will chronologize, and continue by examining potential for exploitation of stretching artifacts in some contemporary algorithms, and propose a quantification of this effect.
Engineering Brief 9 (Download now)

EB2-2 Activity Flow in Music Equalization: The Cognitive and Creative Implications of Interface DesignJosh Mycroft, Justin Paterson, QMUL, University of West London
The mixing desk metaphor found in many Digital Audio Workstations (DAW) creates a quantitative visual display that is highly structured and segmented. While this is useful for transmitting large amounts of quantitative data it can inhibit the more intuitive and performative aspects inherent in music mixing. This paper's focus is the cognitive and creative issues encountered using current music production software equalizers and the influence they exert on the initial approach, task workflow, and final output of the user. Equalizers have been chosen to exemplify this, due to their pivotal balance between aural and visual modalities. The paper draws conclusions as to the effectiveness of current software equalizer designs and proposes modifications to design.
Engineering Brief 10 (Download now)

EB2-3 The Preset Is Dead; Long Live the PresetJustin Paterson, University of West London
The use of preset sounds in audio production has long been scorned by professional producers, some of whom have cited a lack of originality or integrity, or perhaps a proliferation of homogenization in productions. Despite this, manufacturers have continued to develop ever-larger ranges of presets, now extending beyond instruments and effects, to EQ and even whole channel strips. Developmental work continues to further automate aspects of the mixing process itself. This brief will examine the implications of presets from yesterday to today, and using Logic Pro as a case study, offer some insight into the relevance of this evolving arena to the professional, and the implications to the enthusiast. It will conclude with some conjecture for the future.
Engineering Brief 11 (Download now)

EB2-4 Automated Pure-Tone Audiometry Software Tool with Extended Frequency RangeThomas Bisitz, HörTech GmbH - Oldenburg, Germany; Andreas Silzle, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany
In research institutes and other areas it is necessary to check the hearing of test subjects for listening tests (e.g., for assessing the quality of audio processing algorithms, etc.) by measuring pure tone audiograms. Often, neither a necessary skilled operator nor a special audiometer for high frequencies (>8kHz, important for the evaluation of a lot audio processing algorithms) are available. As an alternative, a software for automated audiogram measurements is presented here. This new kind of software runs on a standard PC with a high-quality sound card and audiological headphones and is operated by the test subject him/herself (self-screening). The implemented adaptive procedure allows fast standard audiogram measurements also for high frequencies up to 16 kHz. The challenges with respect to dynamic range and calibration are discussed.
Engineering Brief 12 (Download now)

EB2-5 A Simple Reliable Power Amplifier with Minimal Component CountJohn Vanderkooy, University of Waterloo - Waterloo, Ontario, Canada & BWGroup, Steyning, UK
We study an audio power amplifier that has three essential active components: two power MOSFETS and one operational amplifier. Such an amplifier will be reliable because MOSFETS have good safe-operating area properties, and there are no small semiconductors that require high voltage ratings. The topology is that of an op-amp directly driving a grounded-source complementary class-B MOSFET output stage. The center-tapped power supply for such an amplifier is floating, so each channel must have a separate supply, and there must be a small ±15-volt supply for the op-amp as well. We discuss the design and study the amplifier with simulations and an experimental prototype. It achieves good performance.
Engineering Brief 13 (Download now)

EB2-6 Parametric Study of Magnet System Topologies for MicrospeakersHolger Hiebel, NXP Semiconductors Austria GmbH, "Sound Solutions"
A parametric simulation study was done in order to compare 3 different electrodynamic magnet system topologies: center-magnet, ring-magnet, and double-magnet (combined inner and outer magnet ring). The study is based on a row of simulations of the BL-factor (FEM and coil winding calculation), moving mass and effective radiating area of a microspeaker design where the inner coil diameter was changed. The dependency of the sound pressure level, the electrical quality factor, and the resonance frequency in a closed box on the inner coil diameter were derived to yield comparison charts for the 3 topologies.
Engineering Brief 14 (Download now)

EB2-7 Signal Processing Applications for Automotive AudioRobert Cadena, Visteon Corporation - Van Buren Township, MI, USA
The automotive environment presents unique challenges to audio playback. Modern technology such as smart phones and high-efficiency power trains have created a new generation of audio sources and the need for audio systems capable of dealing with them. This Engineering Brief will introduce emerging automotive audio algorithms (listed below) and their design considerations.
Engineering Brief 15 (Download now)

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