WO2010116387A1

WO2010116387A1 - Compression speaker

Info

Publication number: WO2010116387A1
Application number: PCT/IT2009/000144
Authority: WO
Inventors: Emilian Capucci; Romolo Toppi
Original assignee: Fabbrica Italiana Altoparlanti S.P.A.
Priority date: 2009-04-06
Filing date: 2009-04-06
Publication date: 2010-10-14

Abstract

Speaker comprising a diaphragm (1) which is mechanically connected to a coil (3) for generating sound waves and is arranged under an output mouth (4) of a main body (2) for transmitting the sound waves outwards, wherein a phase plug (7) is arranged between the diaphragm (1) and the output mouth (4), is provided with a plurality of radial slits (8) which connect the diaphragm (1) with the output mouth (4) and has a substantially frustoconical shape with the smaller base substantially coinciding with the output mouth (4).

Description

COMPRESSION SPEAKER

The present invention relates to a compression speaker, and in particular to a speaker provided with a particular phase plug arranged between the diaphragm and the output mouth.

Known compression ^' speakers comprise a diaphragm which is mechanically connected to a coil for generating sound waves and is arranged under an output mouth of a main body for transmitting the sound waves outwards. The sound waves are compressed by a phase plug which is arranged between the diaphragm and the output mouth and is provided with a plurality of radial slits which connect the diaphragm with the output mouth.

The main body of these known speakers comprises a small conical link horn for ensuring the compatibility with the standard diameters of the throat of the horns which can be fixed to the output mouth of the main body. However, when these known speakers are joined to a horn, the presence of the link horn generally creates a geometrical discontinuity in the expansion profile, thus inducing diffraction and reflection phenomena which make the sound emission at high frequencies not very controllable, thus causing a non-linearity of the response and a loss of the directivity control. ^■ It is therefore an object of the present invention to provide a speaker, which is free from said disadvantages. Said object is achieved with a speaker, whose main features are disclosed in the first claim, while other features are disclosed in the remaining claims.

Thanks to the particular shape and to the particular arrangement of the phase plug, the speaker according to the present invention ensures the presence of the desired wave front directly at the output mouth, with consequent advantages in terms of regularity of the frequency response and of the directivity control.

In particular, the wave front at the output mouth of the speaker turns out to be coherent and known, preferably plane, so that the acoustic performances undergo a clear improvement, since the propagation of the sound waves at high frequencies occurs in a controlled and non-chaotic manner. Furthermore, thanks to the particular shape of the radial slits of the phase plug, the propagation of the sound waves from the diaphragm to the output mouth is improved.

Further advantages and features of the speaker according to the present invention will become clear to those skilled in the art from the following detailed and non-limiting description of an embodiment thereof with reference to the attached drawings, wherein: figure 1 shows a side view of the speaker; figure 2 shows a top view of the speaker of figure 1 ; figure 3 shows a bottom view of the speaker of figure 1 ; figure 4 shows section IV-IV of figure 3 ; - figure 5 shows section V-V of figure 3; figure 6 shows an enlarged perspective view of the phase plug of the speaker of figure 1 ; figure 7 shows a first cross-section of the phase plug of figure 6; and figure 8 shows a second cross-section of the phase plug of figure 6. Referring to figures 1 to 5, it is seen that the speaker according to the present invention comprises in a known way a diaphragm 1 which is arranged in a main body 2 and is mechanically connected to a coil 3 for generating sound waves. Diaphragm 1 is arranged in a substantially coaxial manner under an output mouth 4 made in main body 2 for transmitting the sound waves outwards, in particular through a horn 5 which is fixed to main body 2 by means of screws 6 and has a throat substantially coincident with output mouth 4. In the present embodiment diaphragm 1 has a substantially annular shape, while output mouth 4 has a substantially circular shape. A phase plug 7 having a substantially frustoconical shape, with a circular or elliptical section, is arranged between diaphragm 1 and output mouth 4, in particular in a seat made in main body 2 with a shape complementary to the shape of phase plug 7. The smaller base of phase plug 7 substantially coincides with output mouth 4.

Referring also to figures 6 to 8, it is seen that phase plug 7 is provided with a plurality of radial slits 8 which connect diaphragm 1 with output mouth 4. The area of the cross-section of radial slits 8 increases from diaphragm 1 to output mouth 4. In particular, the cross-section of radial slits 8 has a shape of a circular or elliptical annulus sector, in which the central angle increases from diaphragm 1 to output mouth 4. Also the radial size R of radial slits 8 increases from diaphragm 1 to output mouth 4. The diagonal of the cross-section of radial slits 8 is shorter than the shortest wavelength in the frequency response of the speaker. The larger base of phase plug 7 includes an annular protrusion 9 having a substantially triangular profile with a vertex 10 facing diaphragm 1. Also the profile of diaphragm 1 is substantially triangular, wherein the vertex adjacent to vertex 10 of annular protrusion 9 of phase plug 7 is joined to coil 3.

Possible modifications and/or additions may be made by those skilled in the art to the hereinabove disclosed and illustrated embodiment while remaining within the scope of the following claims.

Claims

1. Speaker comprising a diaphragm (1) which is mechanically connected to a coil (3) for generating sound waves and is arranged under an output mouth (4) of a main body (2) for transmitting the sound waves outwards, wherein a phase plug (7) is arranged between the diaphragm (1) and the output mouth (4) and is provided with a plurality of radial slits (8) which connect the diaphragm (1) with the output mouth (4), characterized in that the phase plug (7) has a substantially frustoconical shape with the smaller base substantially coinciding with the output mouth (4).

2. Speaker according to the previous claim, characterized in that the phase plug

(7) is arranged in a seat made in the main body (2) with a shape complementary to the shape of the phase plug (7).

3. Speaker according to one of the previous claims, characterized in that the area of the cross-section of the radial slits (8) increases from the diaphragm (1) to the output mouth (4) .

4. Speaker according to one of the previous claims, characterized in that the cross-section of the radial slits (8) has a shape of a circular or elliptical annulus sector, in which the central angle increases from the diaphragm (1) to the output mouth (4).

5. Speaker according to one of the previous claims, characterized in that the radial size (R) of the radial slits (8) increases from the diaphragm (1) to the output mouth (4).

6. Speaker according to one of the previous claims, characterized in that the diagonal of the cross-section of the radial slits (8) is shorter than the shortest wavelength in the frequency response of the speaker.

7. Speaker according to one of the previous claims, characterized in that the diaphragm (1) has a substantially annular shape.

8. Speaker according to the previous claim, characterized in that the larger base of the phase plug (7) includes an annular protrusion (9) having a substantially triangular profile with a vertex (10) facing the diaphragm (1).

9. Speaker according to the previous claim, characterized in that the profile of the diaphragm (1) is substantially triangular, wherein the vertex adjacent to the vertex (10) of the annular protrusion (9) of the phase plug (7) is joined to the coil (3).