| 摘要 |
PROBLEM TO BE SOLVED: To obtain a flat sound pressure frequency characteristic in a intermediate area in particular by providing a magnetic circuit formed by respectively arranging a soft magnetic body at both sides of magnets provided side by side in the magnetic circuit having a structure in which at least three rows of magnets are provided side by side. SOLUTION: In the magnetic circuit having the structure where at least three rows of magnets 31, 33, and 35 are provided side by side, the magnetic circuit formed by arranging soft magnetic bodies 11 and 12 on the both sides of the magnets 31, 33 and 35 provided side by side is provided. Magnetic flux density in a magnetic gap where a voice coil is arranged can be uniformized by arranging the bodies 11 and 12 for magnetic induction outside the both sides of the magnets 31 and 35 so as to be provided side by side with them in a thickness direction, and then, driving force can be maintained at a constant level. As a result, a sound pressure frequency characteristic can be made flatter than that of a speaker using a conventional magnetic circuit, and a flat sound pressure frequency characteristic can be obtained in the intermediate area in particular.
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