Journal of the AES

2010 June - Volume 58 Number 6

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Papers

Theory and Practice of Modified Frequency Modulation Synthesis

Authors:Lazzarini, Victor; Timoney, Joseph
Affiliation:Sound and Music Technology Group, National University of Ireland, Maynooth, Ireland
Page:459

Frequency modulation synthesis of musical instruments has been studied for years and its limitations are well known. By modifying the basic closed-form equations to work in the complex domain, an alternative method that can overcome some of these limitations is presented. The proposed approach provides a smoothly evolving spectrum with regard to variations in modulation index. A phase-synchronous version is discussed with application to resonant and formant synthesis. A comparison with the classical frequency modulation approach illustrates its advantages. Adaptive applications of the algorithm are introduced and explored.

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Frequency Dependence of Damping and Compliance in Loudspeaker Suspensions

Authors:Thorborg, Knud; Tinggaard, Carsten; Agerkvist, Finn; Futtrup, Claus
Affiliation:ScanSpeak A / S, Videbaek, Denmark; Viby Sjaelland, Denmark; Acoustic Technology DTU-Elektro, Technical University of Denmark, Lyngby, Denmark
Page:472

Commonly used materials for loudspeaker suspensions have been shown to have viscoelastic properties, best known is the “creep” effect. This phenomenon, while known, is normally of little interest because it is primarily a dc issue outside of the audio frequency range. However, this viscoelasticity phenomenon also has a frequency-dependent influence on damping and compliance. Because damping is inversely proportional to frequency, a simplified model only including frequency-dependent damping is presented. The model provides an acceptable fit for empirical data.

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Engineering Reports

Discrimination of MP3-Compressed Musical Instrument Tones

Authors:Lee, Chung; Horner, Andrew
Affiliation:Department of Computer Science and Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong
Page:487

In order to determine the acceptable compression rate for MP3 codecs, listeners were asked to discriminate various rates for eight different musical instruments. The clarinet proved to be most sensitive to compression even at rates approaching 128 kbps, while the horn was least sensitive at rates of 56 kbps. Discrimination scores were strongly correlated with the signal-to-mask ratio and spectral irregularity. Spectral error accounted for more than 80% of the discrimination variance. Objective measures of the sound source predict most of the discrimination sensitivity.

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Synthesis of the Dan Trahn Based on a Parameter Extraction System

Authors:Cho, Sang-Jin; Chong, Ul-Pil; Cho, Sang-Bock
Affiliation:Department of Electrical Engineering, University of Ulsan, Ulsan, Korea; Department of Computer Engineering and Information Technology, University of Ulsan, Ulsan, Korea
Page:498

The authors present a model for synthesizing the sound of the Vietnamese plucked string instrument called the dan tranh. The model’s parameters are estimated from the short-time Fourier transform, and the synthesized sound is generated using a single delay loop. The excitation, which is determined by the body structure of the instrument, plays an important role in achieving a natural sound. The results are compared to both the Korean gayageum with silk strings and the acoustic guitar with steel strings.

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Standards and Information Documents

AES Standards Committee News

Page:508 Download:PDF (701KB)

Recoding data set; control, monitoring, and connection management for audio networks; surround microphone connector; polar radiation of arrays and clusters; digital input/output interfacing; audio-file transfer and exchange; audio applications of networks; transfer technologies; storage and handling of Media

Features

Wireless Microphones for Live Sound

Author:Rumsey, Francis
Page:513

Significant changes in regulation have affected the operation of wireless microphones in recent years. During two live sound seminars held at the 127th Convention in New York last year, experts in the field reviewed the current state of play, particularly considering the increased competition for spectrum "real estate" in the UHF band. Ways of making the best use of wireless microphone technology in practical applications were proposed, including antenna arrangements and frequency planning.

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41st Conference, London, Call for Papers

Page:533 Download:PDF (402KB)

Departments

News of the Sections Page:525 PDF (1.1MB)

Sound Track Page:529 PDF (450KB)

Upcoming Meetings Page:529 PDF (450KB)

New Products and Developments Page:530 PDF (422KB)

Membership Information Page:531 PDF (467KB)

Advertiser Internet Directory Page:532 PDF (444KB)

In Memoriam Page:534 PDF (717KB)

Sections Contacts Directory Page:536 PDF (459KB)

AES Conventions and Conferences Page:544 PDF (525KB)

Extras

Table of Contents PDF (405KB)

Cover & Sustaining Members List PDF (78KB)

AES Officers, Committees, Offices & Journal Staff PDF (439KB)