2002 December, Vol 50 Number 12

CONTENT

PAPERS

Frequency-Zooming ARMA Modeling of Resonant and Reverberant Systems
Matti Karjalainen, Paulo A. A. Esquef, Poju Antsalo, Aki Mäkivirta, and Vesa Välimäki   1012
Complex linear, time-invariant modeling of a system with high modal density is extremely difficult, for example, room reverberation. A frequency-zooming method based on an extension of previous techniques is explored for high-resolution modeling of systems with many poles and zeros. Such models can be used not only to generate accurate time responses, but also to serve as the basis for inverse filtering and equalization.

Passive All-Pass Crossover System of Order 3 (Low Pass) + 5 (High Pass), Incorporating Driver Parameters
Neville Thiele   1030
A third-order low-pass channel combined with a fifth-order high-pass channel can be designed to produce an overall all-pass crossover between the two channels. Because the two channels are approximately in phase over the crossover region, the approach is more tolerant to variations in driver parameters and physical offsets in the cabinet. Although the approach adds a modest cost, the benefits appear to justify the incremental complexity.

Experimental Evidence of Cooperation Phenomena Application to a Loudspeaker with Rub
Fernando Bolaños   1039
Unlike a linear system, which preserves the frequency integrity of each signal component, a nonlinear system can shift energy from one spectral component to another. Although the theoretical basis of energy cooperation is well known, the author empirically demonstrates the phenomena in an electroacoustic experiment involving a voice coil with friction. When random noise is added to a sine wave, the nonlinear process moves energy from the noise to the sine frequency. This is analogous to the way that a limit-cycle oscillator converts the dc of the power supply into a spectral component.

ENGINEERING REPORTS

Iterative Combinatorial Basis Spectra in Wavetable Matching
Alan Ng and Andrew Horner   1054
As an alternative to the combinatorial approach to wavetable synthesis, an iterative method is proposed to increase the computational efficiency while achieving a comparable effectiveness. The algorithm was evaluated using tones from the trumpet, tenor voice, and Chinese pipa (a plucked stringed instrument). The number of wavetables dramatically influenced the rms error. In addition, subjective listening tests determined the degree to which the synthesized signal was equivalent to the original.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   1064
Calls for Comment: MADI revision, life expectancy of CD-ROM; Internet audio; audio metadata

FEATURES

Moving Digital Audio, Part 1   1068
2002/2003 AES International Sections Directory   1076
Education News   1106
Call for Nominations for Board of Governors   1113
Call for Awards Nominations   1114
11th Tokyo Regional Convention, Call for Papers   1124
115th Convention, New York, Call for Papers   1125
114th Convention, Amsterdam, Call for Workshops Participants   1126
Bylaws: Audio Engineering Society, Inc.   1127
Index to Volume 50   1132

DEPARTMENTS

News of the Sections   1101
Sound Track   1108
New Products and Developments   1109
Upcoming Meetings   1110
Available Literature   1111
AES Annual Report   1115
Membership Information   1116
Advertiser Internet Directory   1119
In Memoriam   1120
AES Conventions and Conferences   1144

FPO For the cover:

2002 December, Vol 50 Number 12

spine: 2002 December, Vol 50 Number 12