Archives of Acoustics, 42, 1, pp. 71–81, 2017
10.1515/aoa-2017-0008

Comparative Measurements on Loudspeaker Distortion: Current vs. Voltage Control

Esa MERILÄINEN
http://www.current-drive.info
N/A
Finland

Modulation and harmonic distortion produced by ordinary moving-coil direct-radiator drive units are measured under current control and voltage control. A realistic two-tone test signal is used to investigate the detrimental effect of the voice coil electromotive forces on the voltage-to-current conversion that is critical with voltage control. Dramatic improvements in distortion performance are obtained with current control. Current nonlinearities in voltage-controlled speakers are shown to be the dominant source of modulation and odd harmonic distortions at signal frequencies above the fundamental resonance region. Currents in conductive voice coil formers also seem to be significant sources of distortion; with current control and non-conductive formers, odd harmonics and related modulation products virtually vanished in the upper midrange.
Keywords: current driving; current control; loudspeaker distortion; current distortion; inductance nonlinearity; voice coil former
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Copyright © Polish Academy of Sciences & Institute of Fundamental Technological Research (IPPT PAN).

References

Bortoni R., Filho S.N., Silva H.S. (2007), Effects of Acoustic Damping on Current-Driven Loudspeakers, Dissertation presented at the 122nd Convention of the Audio Engineering Society, Vienna.

Dobrucki A. (2011), Nonlinear Distortions in Electroacoustic Devices, Archives of Acoustics, 36, 2, 437– 460.

Klippel W. (2006), Tutorial: Loudspeaker Nonlinearities – Causes, Parameters, Symptoms, J. Audio Eng. Soc., 54, 10, 907–939.

Lee R. (1955), Electronic Transformers and Circuits, 2nd edition, John Wiley & Sons, New York.

Mazin V.Y. (1999), Modeling of Magnetic Hysteresis and its Influence on Harmonic Distortion in Electrodynamic Loudspeakers, Dissertation presented at the 106th Convention of the Audio Engineering Society, Munich.

Meriläinen E. (2010), Current-Driving of Loudspeakers, CreateSpace publishing platform, Charleston, ISBN 9781450544009.

Merit B., Novak A. (2015), Magnet-Only Loudspeaker Magnetic Circuits: A Solution for Significantly Lower Current Distortion, J. Audio Eng. Soc., 63, 6, 463–473.

Mills P.G.L., Hawksford M.O.J. (1989), Distortion Reduction in Moving-Coil Loudspeaker Systems Using Current-Drive Technology, J. Audio Eng. Soc., 37, 3, 129–148.

Pillonnet G., Sturtzer E., Rossignol T., Tournier P., Lemarquand G. (2013), Distortion Improvement in the Current Coil of Loudspeakers, Dissertation presented at the 134th Convention of the Audio Engineering Society, Rome.

Schneider H., Agerkvist F., Knott A., Andersen M.A.E. (2015), Investigation of Current Driven Loudspeakers, Dissertation presented at the 138th Convention of the Audio Engineering Society, Warsaw.




DOI: 10.1515/aoa-2017-0008