AES New York 2011
Paper Session P4

P4 - Loudspeakers

Thursday, October 20, 2:30 pm — 4:30 pm (Room: 1E09)

Alex Voishvillo, JBL Professional

P4-1 Subwoofers in Rooms: Equalization of Multiple SubwoofersJuha Backman, Nokia Corporation - Espoo, Finland, Aalto University, Espoo, Finland
The effectiveness of multiple subwoofers in controlling low-frequency room modes can be improved through designing individual equalization for each of the subwoofers. The paper discusses two strategies toward equalizer design, including individual equalization of multiple subwoofer responses, minimizing the total energy radiated to the room, and optimization for minimizing sound field variation. The frequency responses and sound field distributions obtained using these methods are compared to the results of conventional equalization and modal control only through loudspeaker placement.
Convention Paper 8471 (Purchase now)

P4-2 A Systematic Approach to Measurement Limit Definitions in Loudspeaker ProductionGregor Schmidle, NTi Audio AG - Schaan, Liechtenstein
A typical end-of-line loudspeaker test comprises ten or more different parameters tested. Each parameter has its own pass/fail limits contributing to the overall test result of the loudspeaker and therefore to the yield of the production line. This paper gives a comprehensive overview about commonly used limit calculation methods and procedures in the industry. It also delivers a systematic guidance for choosing the right limit scheme for maximizing yield, quality, and throughput.
Convention Paper 8472 (Purchase now)

P4-3 Inverse Distance Weighting for Extrapolating Balloon-Directivity-PlotsJoerg Panzer, R&D Team - Salgen, Germany; Daniele Ponteggia, Audiomatica Srl - Firenze, Italy
This paper investigates an extrapolation for missing directivity-data in connection with Balloon-Plots. Such plots display the spherical directivity-pattern of radiators and receivers in form of contoured sound pressure levels. Normally the directivity-data are distributed evenly so that at each point of the display-sphere there would be sufficient data-points. However, there are circumstances where we want to display data that are not evenly distributed. For example, there might be only available the horizontal and vertical scans. The proposed Inverse Distance Weighting method is a means to extrapolate into these gaps. This paper explains this method and demonstrates some examples.
Convention Paper 8473 (Purchase now)

P4-4 Mechanical Fatigue and Load-Induced Aging of Loudspeaker SuspensionWolfgang Klippel, Klippel GmbH - Dresden Germany
The mechanical suspension becomes more and more compliant over time changing the loudspeaker properties (e.g., resonance frequency) significantly. This aging process is reproducible and the decay of the stiffness can be modeled by accumulating the apparent power supplied to the suspension part and using an exponential relationship. The free parameters of this model are estimated from empirical data provided by on-line monitoring or intermittent measurements during regular power tests or other kinds of long-term testing. The identified model can be used to predict the load-induced aging for music or test signals having arbitrary spectral properties. New characteristics are being introduced that simplify the quality assessment of suspension parts and separate mechanical fatigue from the initial break-in effect. Practical experiments are performed to verify the model and to demonstrate the diagnostic value for selecting optimal suspension parts providing sufficient long-term stability.
Convention Paper 8474 (Purchase now)

Information Last Updated: 20111005, mei

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