| 摘要 |
PROBLEM TO BE SOLVED: To provide a speaker of a magnetic shield type with a simple configuration, where a magnetic force in a magnetic air gap to drive a diaphragm is increased. SOLUTION: This speaker is provided with a pot yoke 20 with a center pole 20a, a 1st ring magnet 21 placed at a bottom 20b of the pot yoke 20, a 1st plate 22 on the 1st ring magnet 21 with a 1st magnetic air gap 23 formed between an inner circumferential face of the plate 22 and an outer circumferential face of the center pole 20a, a 2nd ring magnet 24 of the same polarity as the 1st ring magnet 21 placed on the 1st plate 22, a 2nd plate 25 on the 2nd ring magnet 24 with a 2nd magnetic air gap 26 formed between the inner circumferential face of the plate 25 and the outer circumferential face of the center pole 20a, and a 3rd plate 27 on the upper end face of the pot yoke 20 with a 3rd magnetic air gap 28 formed between an inner circumferential face of the plate 27 and the outer circumferential face of the center pole 20a. The diaphragm 6 is driven by the magnetic field of the magnetic air gap 26 which is the strongest among those in the 1st, 2nd and 3rd magnetic air gaps 23, 26 and 28.
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