AES Dublin 2019
Paper Session P06
P06 - Loudspeaker: Part 3
Thursday, March 21, 09:00 — 11:00 (Meeting Room 3)
Bjørn Kolbrek, Celestion - Ipswich, UK
P06-1 Dynamic Driver Current Feedback Methods—Juha Backman, Huawei Technologies - Tampere, Finland; Genelec Oy - Iisalmi, Finland
Current feedback is a versatile method of modifying the behavior of a loudspeaker driver with opportunity for linearization and matching the driver to the enclosure design targets, but depending on the chosen approach a potential risk of increasing the effects of either voice coil impedance variation or driver mechanical parameter nonlinearity, and the current feedback approach needs to be designed to keep these effects well controlled for the intended application. This work compares using a nonlinear simulation model various forms of current feedback, including current drive, finite positive or negative amplifier resistances, negative resistance with reactance. This final part of the work extends the examples given in the earlier papers and presents a feedback approach that would appear to offer benefits in both distortion and thermal compression control.
Convention Paper 10152 (Purchase now)
P06-2 Impact of the Coupling Factor on Lossy Voice Coil Impedance—Isao Anazawa, NY Works - Toronto, ON, Canada
The voice coil impedance frequency dependence due to Eddy current, skin, and proximity effects (Eddy Losses) becomes more apparent as the frequency becomes higher. The theory is that the magnitude of lossy impedance frequency dependence is vw . However in the majority of real loudspeakers, the impedance frequency dependence was empirically found to be clearly higher than this. A voice coil blocked impedance model was developed based on a structure that applies a transformer for the voice coil inductance as the primary winding. Surrounding conductive material is treated as an impedance connected to the secondary winding. The model successfully describes the blocked impedance frequency dependence that agreed at a high degree of accuracy with the actual samples. Also the model showed intricate connections between the transformer coupling coefficient k and the magnitude of frequency dependency.
Convention Paper 10153 (Purchase now)
P06-3 Compact Stereo Loudspeakers with Dipole Processing—Christof Faller, Illusonic GmbH - Uster, Zürich, Switzerland; EPFL - Lausanne, Switzerland
Compact stereo loudspeakers have become increasingly popular. One category of these use side-firing left and right transducers featuring a certain spatial effect due to the transducers’ directivity at high frequencies. The presented technique increases the spatial effect by controlling directivity at low/medium frequencies, where the transducers have low directivity. A multi-band filter network is used to increase directivity at these frequencies by partially reproducing the stereo signal with dipole directivity pattern. The problem of interference between left and right direct and dipole reproduced sound is addressed.
Convention Paper 10154 (Purchase now)
P06-4 Poster Introductions 4—N/A
The purpose of Poster Introductions at the end of certain paper sessions is to give the poster authors a chance to briefly outline what is in their paper and encourage people to come to their poster session and ask questions. • Real-Time Measurement System Detecting Tonal Components and Determining Their Audibility in Environmental Noise—Magdalena Matys; Kamil Piotrowski; Tadeusz Wszolek; Bartlomiej Kukulski • Localization Accuracy of First Order Ambisonics in the Vertical Plane across Multiple Horizontal Positions—Connor Millns; Hyunkook Lee; Maksims Mironovs • A Case Study on the Perceptual Differences in Finite-Difference Time-Domain-Simulated Diffuser Designs—Julie Meyer; Lauri Savioja; Tapio Lokki • Analysis of Polish Web Streaming Loudness—Piotr Cieslik; Karolina Szybinska