Abstract: An in-ear earphone, including a casing, a speaker, and an attenuation guide, is provided. The casing includes a sound outlet and a first through hole. An inside of the casing has a first accommodating space. The speaker is disposed in the first accommodating space. The casing defines a front cavity and a rear cavity by the speaker. The attenuation guide is formed in the casing and includes at least a first attenuation channel and a second attenuation channel. The first attenuation channel has a first inlet and a first outlet. The first inlet is connected to the first through hole. The second attenuation channel has a second inlet and a second outlet. The second inlet, the first outlet, and the rear cavity are acoustically connected, and the second outlet is connected to the front cavity.

Abstract: An earphone including a housing, a speaker and an eartip is provided. The housing has an accommodating space and a first sound outlet communicated with each other. The speaker is disposed in the accommodating space. The eartip is assembled to the housing. The eartip has a second sound outlet and an incline extension surface. The incline extension surface is configured to fit into a cavum of a user's auricle and withstand an antihelix of the user's auricle.

Abstract: An earphone including a housing, a speaker and an eartip is provided. The housing has an accommodating space and a first sound outlet communicated with each other. The speaker is disposed in the accommodating space. The eartip is assembled to the housing. The eartip has a second sound outlet and an incline extension surface. The incline extension surface is configured to fit into a cavum of a user's auricle and withstand an antihelix of the user's auricle.