Journal of the Audio Engineering Society

2003 April - Volume 51 Number 4

Papers


[feature article] Game Audio makes up one-third of a multibillion-dollar gaming industry. It has been suggested that the industry accounts for between 6 and 9 billion dollars a year, so it is of major importance for audio engineers. At this workshop at the AES 113th Convention in Los Angeles a selection of the key experts on the topic shared the wealth of their experience and knowledge.

[feature article] MIDI is a widely used means of controlling musical instruments and other devices, having created and supported a market for remote-controlled musical instruments and other equipment for 20 years. This article considers the current status of MIDI, some recent enhancements, and possible future directions.

Author's Reply to Letter to the editor

Reply to Letter to the editor

Letter to the editor

The Virtual Loudspeaker Cabinet

Authors: Wright, Julian R.

A method is presented for increasing the acoustic compliance of a loudspeaker cabinet by introducing activated carbon into the enclosure. The process is explained and working examples are discussed.

On the Acoustic Radiation from a Loudspeaker`s Cabinet

Authors: Bastyr, Kevin J.; Capone, Dean E.

A scanning laser Doppler vibrometer and a computational boundary-element model are used to study the acoustic radiation from loudspeaker cabinets. In contrast to the research findings of Skrodzka, loudspeaker cabinets are shown to contribute significantly to the total radiated pressure at their lower resonance frequencies. This occurs because, despite a cabinet's relatively small surface velocity, its radiation efficiency is many times greater than that of the drivers. The radiation from two different versions of NHT's model 2.9 loudspeaker is investigated. The first is a standard production 2.9, the second a 2.9 without the standard internal bracing. A comparison of their performance yields insight into the effects of wall bracing location: stiffer cabinets with lower amplitude wall vibrations do not always radiate less sound.

Automatic beat tracking consists of estimating the number of beats per minutes at which a music track is played and identifying exactly when these beats occur. Applications range from music analysis, sound-effect synchronization, and audio editing to automatic playlist generation and deejaying. An off-line beat-tracking technique for estimating a time-varying tempo in an audio track is presented. The algorithm uses an MMSE estimation of local tempo and beat location candidates, followed by a dynamic programming stage used to determine the optimum choice of candidate in each analysis frame. The algorithm is efficient in its use of computation resource, yet provides very good results on a wide range of audio tracks. The algorithm details are presented, followed by a discussion of the performance and suggestions for further improvements.

The Bidirectional Microphone: A Forgotten Patriarch

Authors: Streicher, Ron; Dooley, Wes

Despite being one of the progenitors of all modern microphones and recording techniques, the bidirectional pattern is still not very well understood. Its proper and effective use remains somewhat of a mystery to many recording and sound-reinforcement engineers. The bidirectional microphone is examined from historical, technical, and operational perspectives. It is reviewed how it was developed and exists as a fundamental element of almost all other single-order microphone patterns. In the course of describing how this unique pattern responds to sound waves arriving from different angles of incidence, it is shown that very often it can be employed successfully where other more commonly used microphones cannot.

Engineering reports


The Virtual Loudspeaker Cabinet

Standards and Information Documents


AES Standards Committee News

Features


24th Conference Preview, Banff

    Calendar

    Program

    Registration Form

MIDI and Musical Instrument Control

Game Audio: Follow-up to Workshop at 113th Convention

Departments


Review of Acoustical Patents

News of the Sections

Upcoming Meetings

New Products and Developments

Advertiser Internet Directory

Membership Information

AES Special Publications

Sections Contacts Directory

AES Conventions and Conferences

Extras


Cover & Sustaining Members List

VIP List & Editorial Staff

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