Dynamic headphones
Provided is a dynamic headphone that has a small size but makes a larger-diameter headphone unit mountable thereon, the dynamic headphone including a highly reliable acoustic channel that acoustically connects a front air chamber and a back air chamber to each other. A headphone case 20 houses a headphone unit 50 therein, and includes a back air chamber C 2 on a back side of the headphone unit 50 . The headphone case 20 includes: a back air chamber forming portion 40 that forms the back air chamber C 2 ; and a mount portion 30 integrally provided to an opening end of the back air chamber forming portion 40 , the headphone unit 50 being mounted in the mount portion 30 . An acoustic channel 70 is provided between the mount portion 30 and the headphone unit 50.
1. A dynamic headphone comprising:
a headphone unit including: a diaphragm including a voice coil; a magnetic circuit portion including a magnetic gap in which the voice coil is placed; and a unit frame that supports the diaphragm and the magnetic circuit portion;
a headphone case that houses the headphone unit therein, and includes a back air chamber forming portion forming a back air chamber having a predetermined volume on a back side of the headphone unit, and a mount portion integrally provided to an opening end of the back air chamber forming portion, the headphone unit being mounted in the mount portion, wherein the mount portion includes a cylindrical portion having a diameter larger than that of the unit frame, and an engagement portion bent inward from a front end of the cylindrical portion to face a peripheral edge part of the unit frame;
an ear pad that is provided to an outer peripheral edge part of the headphone case and adapted to surround an ear of a wearer on a sound emitting surface side of the headphone unit, the ear pad being adapted to form a front air chamber having a predetermined volume between the ear and a front side of the headphone unit when the dynamic headphone is fitted over the ear of the wearer;
an acoustic channel provided between the mount portion and the headphone unit, extending along inner surfaces of the engagement portion and the cylindrical portion to acoustically connect the front air chamber and the back air chamber to each other; and
an acoustic resistance material provided in the acoustic channel.
2. The dynamic headphone according to claim 1 , wherein the ear pad is provided on an outer surface side of the engagement portion.
3. The dynamic headphone according to claim 1 , wherein the engagement portion is arranged on the ear pad, and the cylindrical portion extends from an outer peripheral edge of the engagement portion to integrally connect with the opening end of the back air chamber forming portion so that the acoustic channel is formed to communicate between the back air chamber and the front air chamber.
4. The dynamic headphone according to claim 3 , further comprising a protector disposed over the front side of the headphone unit to protect the diaphragm,
wherein the unit frame includes a sleeve formed at a peripheral edge thereof to surround and fit the protector.
5. The dynamic headphone according to claim 4 , wherein the protector has a circular shape in which a diameter is less than that of the unit frame to fit into the sleeve of the unit frame.
6. The dynamic headphone according to claim 5 , wherein the acoustic resistance material has an annular shape with an outer peripheral edge extending along the cylindrical portion of the mount portion, so that the acoustic resistance material is disposed between an outer side of the sleeve of the unit frame and the cylindrical portion of the mount portion, and between the protector and the engagement portion of the mount portion.