| 摘要 |
PROBLEM TO BE SOLVED: To configure a small and simple speaker system capable of improving low-pitched sound reproduction limit, using a full-range speaker, a closed cabinet, and a filter circuit including an electric conductor, without degradation in overall characteristics of the speaker, by performing speaker control with electrical characteristics, such as a minimum resonance frequency, electromotive force, and resistance change of the electric conductor connected in series or parallel to the speaker. SOLUTION: Although the type of a dynamo-electric speaker is used as the structure of the electric conductor, a vibration plate is made unnecessary as the purpose of emitting sound. The electric conductor is formed with a moving-coil 1 for the purpose of electrical characteristics, a lead line 2, a bobbin 3, a holding parts 4 for a vibration system such as a mass regulating material 5, parts for forming a magnetic circuit such as a pole piece 8, a yoke 6, a plate 9, and a magnet 7, as well as a frame 10 for holding the whole, and a terminal 11. The minimum resonance frequency and impedance characteristics can be changed by joining the equivalent mass regulating material 5 to the bobbin wound around the moving-coil of the electric conductor. The target impedance property can be also approached by increase/decrease in resiliency or movement resistance of the moving-coil holding parts of the electric conductor. An electric conductor having a minimum resonance frequency lower than the speaker is connected to the speaker in parallel. Or, an electric conductor using electrical characteristics below a minimum resonance frequency is connected to the speaker in series, by suitably establishing the minimum resonance frequency according to low-pass property of the speaker. COPYRIGHT: (C)2005,JPO&NCIPI
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