Relationship between voice coil fill factor and loudspeaker efficiency

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Abstract

In modern audio systems, utilizing switch-mode amplifiers, the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 3 to 8 Ω are obtained, despite modern audio amplifiers, using switch-mode technology, can be designed to much lower loads. A thorough analysis of the loudspeaker efficiency is presented and its relation to the voice coil fill factor is described. In addition to this the influence of the driver’s mass ratio is investigated and it is found that high mass ratios is beneficial for the efficiency of drivers using high fill factor voice coils. Different voice coil winding strategies are described and their fill factors analysed. It is found that by lowering the nominal resistance of a voice coil, using rectangular wire, one can increase the fill factor. However a practical realization of four voice coil designs could not proof this due to wire insulations issues. Despite that a good correlation between theory and experimental results is found and it is shown that the efficiency is dependent on the fill factor as predicted. Moreover the fill factor of a conventional 4 Ω voice coil was measured to be 53 % which leaves plenty of room for future fill factor optimization.
Original languageEnglish
JournalJournal of Audio Engineering Society
Volume64
Issue number4
Pages (from-to)241-252
ISSN1549-4950
DOIs
Publication statusPublished - 2016

Cite this

@article{c9f44c0af11044fb8a4d64837842a6a5,
title = "Relationship between voice coil fill factor and loudspeaker efficiency",
abstract = "In modern audio systems, utilizing switch-mode amplifiers, the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 3 to 8 Ω are obtained, despite modern audio amplifiers, using switch-mode technology, can be designed to much lower loads. A thorough analysis of the loudspeaker efficiency is presented and its relation to the voice coil fill factor is described. In addition to this the influence of the driver’s mass ratio is investigated and it is found that high mass ratios is beneficial for the efficiency of drivers using high fill factor voice coils. Different voice coil winding strategies are described and their fill factors analysed. It is found that by lowering the nominal resistance of a voice coil, using rectangular wire, one can increase the fill factor. However a practical realization of four voice coil designs could not proof this due to wire insulations issues. Despite that a good correlation between theory and experimental results is found and it is shown that the efficiency is dependent on the fill factor as predicted. Moreover the fill factor of a conventional 4 Ω voice coil was measured to be 53 {\%} which leaves plenty of room for future fill factor optimization.",
author = "Iversen, {Niels Elkj{\ae}r} and Arnold Knott and Andersen, {Michael A. E.}",
year = "2016",
doi = "10.17743/jaes.2016.0006",
language = "English",
volume = "64",
pages = "241--252",
journal = "A E S",
issn = "1549-4950",
publisher = "Audio Engineering Society",
number = "4",

}

Relationship between voice coil fill factor and loudspeaker efficiency. / Iversen, Niels Elkjær; Knott, Arnold; Andersen, Michael A. E.

In: Journal of Audio Engineering Society, Vol. 64, No. 4, 2016, p. 241-252.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Relationship between voice coil fill factor and loudspeaker efficiency

AU - Iversen, Niels Elkjær

AU - Knott, Arnold

AU - Andersen, Michael A. E.

PY - 2016

Y1 - 2016

N2 - In modern audio systems, utilizing switch-mode amplifiers, the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 3 to 8 Ω are obtained, despite modern audio amplifiers, using switch-mode technology, can be designed to much lower loads. A thorough analysis of the loudspeaker efficiency is presented and its relation to the voice coil fill factor is described. In addition to this the influence of the driver’s mass ratio is investigated and it is found that high mass ratios is beneficial for the efficiency of drivers using high fill factor voice coils. Different voice coil winding strategies are described and their fill factors analysed. It is found that by lowering the nominal resistance of a voice coil, using rectangular wire, one can increase the fill factor. However a practical realization of four voice coil designs could not proof this due to wire insulations issues. Despite that a good correlation between theory and experimental results is found and it is shown that the efficiency is dependent on the fill factor as predicted. Moreover the fill factor of a conventional 4 Ω voice coil was measured to be 53 % which leaves plenty of room for future fill factor optimization.

AB - In modern audio systems, utilizing switch-mode amplifiers, the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 3 to 8 Ω are obtained, despite modern audio amplifiers, using switch-mode technology, can be designed to much lower loads. A thorough analysis of the loudspeaker efficiency is presented and its relation to the voice coil fill factor is described. In addition to this the influence of the driver’s mass ratio is investigated and it is found that high mass ratios is beneficial for the efficiency of drivers using high fill factor voice coils. Different voice coil winding strategies are described and their fill factors analysed. It is found that by lowering the nominal resistance of a voice coil, using rectangular wire, one can increase the fill factor. However a practical realization of four voice coil designs could not proof this due to wire insulations issues. Despite that a good correlation between theory and experimental results is found and it is shown that the efficiency is dependent on the fill factor as predicted. Moreover the fill factor of a conventional 4 Ω voice coil was measured to be 53 % which leaves plenty of room for future fill factor optimization.

U2 - 10.17743/jaes.2016.0006

DO - 10.17743/jaes.2016.0006

M3 - Journal article

VL - 64

SP - 241

EP - 252

JO - A E S

JF - A E S

SN - 1549-4950

IS - 4

ER -