High-efficiency low-Bl loudspeakers

Research output: Contribution to journalArticleAcademicpeer-review

17 Citations (Scopus)

Abstract

Normally, low frequency sound reproduction with small transducers is quite inefficient. This is shown by calculating the efficiency and voltage sensitivity for loudspeakers with high, medium, and in particular, low force factors. For these low-force-factor loudspeakers a practically relevant and analytically tractable optimality criterion, involving the loudspeaker parameters, will be defined. Actual prototype bass drivers are assessed according to this criterion. Because the magnet can be considerably smaller than usual, the loudspeaker can be of the moving-magnet type with a stationary coil. These so-called low-Bl drivers have a high efficiency, however, only in a limited frequency region. To deal with that, nonlinear processing essentially compresses the bandwidth of a 20-120Hz bass signal down to a much more narrow span. This span is centered at the resonance of the low-Bl driver, where its efficiency is maximum. The signal processing preserves the temporal envelope modulations of the original bass signal. The compression is at the expense of a decreased sound quality and requires some additional electronics. This new, optimal design has a much higher power efficiency as well as a higher voltage sensitivety than current bass drivers, while the cabinet may be much smaller.

Original languageEnglish
Pages (from-to)579-592
Number of pages14
JournalJournal of the Audio Engineering Society
Volume53
Issue number7-8
Publication statusPublished - 1 Jul 2005
Externally publishedYes

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Loudspeakers
loudspeakers
Magnets
magnets
Sound reproduction
acoustics
Electric potential
power efficiency
signal processing
high voltages
Transducers
Signal processing
transducers
Electronic equipment
coils
envelopes
prototypes
Modulation
Acoustic waves
low frequencies

Cite this

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High-efficiency low-Bl loudspeakers. / Aarts, Ronald M.

In: Journal of the Audio Engineering Society, Vol. 53, No. 7-8, 01.07.2005, p. 579-592.

Research output: Contribution to journalArticleAcademicpeer-review

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