| 摘要 |
PROBLEM TO BE SOLVED: To distinctly reproduce low-pitched sound by providing a spiral duct near a bottom plate and/or a top board of a speaker box and externally emitting air absorbed from the box center from one surface of the box. SOLUTION: Air compressed in a speaker box 1 by a reactive force of a sound emission force of a speaker enters between spiral partitions 19 through a through hole 21 provided in an upper plate center as showed by an arrow C, is given with a centrifugal force by passing through a spiral duct 18, becomes a force toward outside all around a periphery of a box 1, and is emitted in the direction shown by an arrow C' from a duct opening part 18a, then a bottom plate 1D is fixed on a mounting part. Thus, since a compact and lightweight speaker device is not moved backward by a sum of a reactive force of a sound emission force for driving the speaker and a reactive force of a force of the air emitted from the opening part 18a of the duct 18 for magnifying a low- pitched sound and the sum of the sound emission force for driving the speaker and the force of the air emitted from the opening part 18a does not decrease, low-pitched sound emission does not decrease.
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