An acoustic output device comprises a housing, a first loudspeaker and a second loudspeaker disposed in the housing. The first loudspeaker includes a first diaphragm. In the housing, a first front cavity and a first rear cavity are respectively disposed on a front side and a rear side of the first diaphragm, and the first front cavity and the first rear cavity are acoustically coupled with two hole portions disposed on the housing, respectively, to output a first sound wave and a second sound wave. The second loudspeaker includes a second diaphragm. In the housing, a second front cavity and a second rear cavity are respectively disposed on a front side and a rear side of the second diaphragm, and only one of the second front cavity and the second rear cavity is acoustically coupled with a hole portion disposed on the housing to output a third sound wave.

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