Abstract: A gamma tap circuit includes: (i) a first gamma division circuit configured to generate a first gamma tap voltage by performing voltage division of an upper gamma tap voltage and a lower gamma tap voltage, in-sync with a first clock signal CK1 and a first complementary clock signal CK1b, which is 180° out-of-phase relative to CK1, (ii) a second gamma division circuit configured to generate a second gamma tap voltage by performing voltage division of the upper gamma tap voltage and the first gamma tap voltage, in-sync with a second clock signal CK2 and a second complementary clock signal CK2b, which is 180° out-of-phase relative to CK2, and (iii) a third gamma division circuit configured to generate a third gamma tap voltage by performing voltage division of the first gamma tap voltage and the lower gamma tap voltage, in response to CK2 and CK2b, which have a lower frequency relative to CK1 and CK1b.

Abstract: A dual-frequency coaxial earphone includes a dynamic transducer, a cover and a second transducer. The dynamic transducer includes a supporting structure and a vibrating diaphragm mounted to the supporting structure. The cover covers on the supporting structure, so that the cover and the supporting structure define a sound adjusting chamber therein. The cover includes an adjusting orifice communicating with the sound adjusting chamber. The second transducer is adapted to the cover and the second transducer has a first side facing toward the sound adjusting chamber. The sound adjusting chamber is located between the vibrating diaphragm and the second transducer.

Abstract: An earphone device having sound guiding structures includes a housing, a sound guiding cover, a first speaker unit, and a second speaker unit. The housing includes a shell and an acoustic opening. The sound guiding cover is in the shell and includes a front and a rear guide portions. The front guide portion is close to the acoustic opening. The front guide portion includes a first accommodating portion and a guide tube communicating with the first accommodating portion and extending toward the acoustic opening. A guide passage is defined between the front guide portion and the shell. The rear guide portion is away from the acoustic opening relative to the front guide portion. The rear guide portion includes a second accommodating portion communicating with the guide passage. The first speaker unit is in the first accommodating portion. The second speaker unit is in the second accommodating portion.

Abstract: An earphone device having sound guiding structures includes a housing, a sound guiding cover, a first speaker unit, and a second speaker unit. The housing includes a shell and an acoustic opening. The sound guiding cover is in the shell and includes a front and a rear guide portions. The front guide portion is close to the acoustic opening. The front guide portion includes a first accommodating portion and a guide tube communicating with the first accommodating portion and extending toward the acoustic opening. A guide passage is defined between the front guide portion and the shell. The rear guide portion is away from the acoustic opening relative to the front guide portion. The rear guide portion includes a second accommodating portion communicating with the guide passage. The first speaker unit is in the first accommodating portion. The second speaker unit is in the second accommodating portion.

Abstract: A dual-frequency coaxial earphone includes a dynamic transducer, a cover and a second transducer. The dynamic transducer includes a supporting structure and a vibrating diaphragm mounted to the supporting structure. The cover covers on the supporting structure, so that the cover and the supporting structure define a sound adjusting chamber therein. The cover includes an adjusting orifice communicating with the sound adjusting chamber. The second transducer is adapted to the cover and the second transducer has a first side facing toward the sound adjusting chamber. The sound adjusting chamber is located between the vibrating diaphragm and the second transducer.

Abstract: A dual-frequency coaxial earphone includes an earphone housing, a moving coil loudspeaker unit and a balanced armature loudspeaker unit. The earphone housing has a receiving space and an acoustic output orifice. The receiving space communicates with the acoustic output orifice. The moving coil loudspeaker unit is assembled in the receiving space and includes a moving coil vibrating diaphragm and an acoustic transmitting member. The moving coil vibrating diaphragm is assembled to face the acoustic output orifice and includes a central vibrating portion. The acoustic transmitting member includes an acoustic transmitting hole corresponding to the central vibrating portion. The balanced armature loudspeaker corresponds to the moving coil loudspeaker unit and includes an armature vibrating diaphragm.

Abstract: A dual-frequency coaxial earphone includes an earphone housing, a moving coil loudspeaker unit and a balanced armature loudspeaker unit. The earphone housing has a receiving space and an acoustic output orifice. The receiving space communicates with the acoustic output orifice. The moving coil loudspeaker unit is assembled in the receiving space and includes a moving coil vibrating diaphragm and an acoustic transmitting member. The moving coil vibrating diaphragm is assembled to face the acoustic output orifice and includes a central vibrating portion. The acoustic transmitting member includes an acoustic transmitting hole corresponding to the central vibrating portion. The balanced armature loudspeaker corresponds to the moving coil loudspeaker unit and includes an armature vibrating diaphragm.