Diffuser

1. A diffuser which is arranged to face to a diaphragm of a speaker which radiates sound waves comprising:

an opening that a center axis which defines a direction the diaphragm vibrates passes and which defines an inner diameter size;

an almost truncated cone shaped first reflection member which has an annular conical surface which faces to the diaphragm and an annular concave surface which is formed at an opposite side of the annular conical surface, and;

an almost cone shaped second reflection member which is arranged close to the first reflection member and has a conical surface that the center axis passes a vertex of the conical surface,

wherein the diffuser

forms a first acoustic passage that the sound waves propagate and which radiates the sound waves to an outer diameter direction between the diaphragm and the annular conical surface of the first reflection member and

forms a second acoustic passage the sound waves which pass the opening of the first reflection member propagate and which radiates the sound waves to an outer diameter direction between the annular concave surface of the first reflection member and the conical surface of the second reflection member.

2. The diffuser according to claim 1 ,

wherein an outer diameter size of the first reflection member is larger than an outer diameter size of the diaphragm.

3. The diffuser according to claim 1 ,

wherein an outer diameter size of the second reflection member is large than the inner diameter size of the opening of the first reflection member.

4. The diffuser according to claim 1 ,

wherein the first reflection member and the second reflection member are arranged so that at least one part of the second reflection member fits in a concave shaped space that the annular concave surface of the first reflection member defines.

5. The diffuser according to claim 1 ,

wherein a separation distance which is defined in a direction which is along to a cross-sectional curve which defines the annular concave surface of the first reflection member and the center axis is set not to be an equal distance in the cross-sectional curve which defines the conical surface of the second reflection member.

6. The diffuser according to claim 1 further comprising:

a connection member which connects the first reflection member and the second reflection member to form the second acoustic passage.

7. The diffuser according to claim 6 further comprising:

a speaker mounting member which mounts the diaphragm of the speaker by facing to the annular conical surface of the first reflection member and arranging to form the first acoustic passage, and;

a connection member which connects the first reflection member and the speaker mounting member.

8. The diffuser according to claim 1 further comprising:

a grill member which is formed by a member which has breathability and provide at the first acoustic passage and/or the second acoustic passage.

9. The diffuser according to claim 1 ,

wherein the inner diameter size of the first reflection member and the outer diameter size of the second reflection member are defined by a circular shape and

the outer diameter size of the first reflection member is defined by an ellipse shape.

10. A speaker at least comprising:

the diffuser according to any one of claim 1 ; and

the diaphragm which is arranged to face to the diffuser.

11. The speaker according to claim 10 ,

wherein the diaphragm is a cone shape which forms a concave surface which corresponds to the annular conical surface of the first reflection member and has a convex shaped dust cap at a position which faces to the opening of the first reflection member.

12. An electronic musical instrument at least comprising:

the diffuser according to claim 1 ;

a speaker which at least includes the diaphragm which is arranged to face to the diffuser; and

an enclosure which is mounted to the diffuser and the speaker.

13. The electronic musical instrument according to claim 12 ,

wherein a sound absorbing member is further mounted to any one of the annular conical surface of the first reflection member and a mounting surface to which the speaker of the enclosure is mounted.