2004 January/February, Volume 52 Number 1/2 |
CONTENT
PAPERS
Nonlinear Modeling of the Heat Transfer in Loudspeakers
Wolfgang Klippel 3
Traditional analysis of a loudspeaker assumes that thermal and electromechanical models can be represented by linear coupling. Careful examination with a variety of music samples shows that such a model fails to produce accurate results because both systems are intrinsically nonlinear. Especially at low frequencies, the cone movement produces cooling and lower temperatures. A linear approach considers only the input power to the thermal model, while a nonlinear approach includes displacement, velocity, and two components of power dissipation. The nonlinear model is more accurate.
Simultaneous Measurement of Multichannel Acoustic Systems
Alberto González, Pedro Zuccarello, Gema Piñero, and María de Diego 26
Measuring the linear properties of a multichannel audio system can be viewed as a collection of single-channel systems if each channel is measured in isolation. With a large number of input and output channels, a sequential measurements approach takes increasing amounts of time. Using time or frequency multiplexing allows all measurements to be performed simultaneously. A theoretical framework shows the validity of this approach.
A New Thermal Model for Loudspeakers
Fabio Blasizzo 43
Conventional models of temperature in loudspeakers usually ignore the transport of heat from the forced-air convection cooling produced by movement of the loudspeaker cone. Especially at low frequencies in large woofers, force ventilation is the dominant mechanism for heat transport. Because high temperatures produce distortion and degradation, designers need an accurate means of including thermal tradeoffs. Simulation results show that the new model predicts voice-coil temperature more accurately.
ENGINEERING REPORTS
Effect of Arrival at Time Correction on the Accuracy of Binaural Impulse Response Interpolation-Interpolation Methods of Binaural Response
Mitsuo Matsumoto, Susumu Yamanaka, Mikio Toyama, and Hiroaki Nomura 56
When attempting to create a head-related transfer function (HRTF) for a source that can have a continuous location, spatial HRTFs at discrete locations are generally interpolated to get the desired response. Numerous methods of interpolation have already been investigated, but if the methods include time correction, accuracy is improved. Angular shifts in the source location, in addition to changing the response's fine structure, also produce a small time shift because the ears are not located at the center of the head. Azimuth changes produce a time shift.
STANDARDS AND INFORMATION DOCUMENTS
AES Standards Committee News 62
Secretariat note; peak levels; digital input/output interfacing; storage and handling of media; acoustics and sound source modeling
FEATURES
New Horizons in Listening Test Design 65
Novel Surround Sound Microphone and Panning Techniques 74
Updates and Corrections to the 2003/2004 International Sections Directory 81
117th Convention, San Francisco, Call for Papers 99
DEPARTMENTS
News of the Sections 84
Sound Track 90
New Products and Developments 91
Upcoming Meetings 92
Available Literature 93
Membership Information 94
Advertiser Internet Directory 95
In Memoriam 96
AES Special Publications 101
Sections Contacts Directory 106
AES Conventions and Conferences 112
FPO For the cover:
2004 January/February, Volume 52 Number 1/2
spine: 2004 January/February, Volume 52 Number 1/2