WO2004080121A1

WO2004080121A1 - Loudspeaker column

Info

Publication number: WO2004080121A1
Application number: PCT/IB2004/000542
Authority: WO
Inventors: Alessandro Riccobono
Original assignee: Alessandro Riccobono
Priority date: 2003-03-03
Filing date: 2004-03-02
Publication date: 2004-09-16
Also published as: ITVI20030041A1

Abstract

A loudspeaker column comprises an elongate box-like cabinet (2) defining a longitudinal axis (L), a plurality of loudspeakers (3, 3') disposed in the cabinet in adjacent positions along said longitudinal axis (L). Each loudspeaker (3, 3') has an outer housing (4), to which a diaphragm (6, 6') is elastically anchored for sound reproduction. The loudspeakers (3, 3') are of the type that has a cap- or dome-shaped diaphragm (6, 6'), with at least one unbroken and continuous substantially hemispherical central portion (16, 16'). Such central portion (16, 16') may be concave with an outwardly facing concavity or convex with an outwardly facing convexity.

Description

LOUDSPEAKER COLUMN

Technical field

The invention finds application in the field of sound reproducing apparatuses and specifically concerns a loudspeaker column.

The inventive loudspeaker system is particularly suitable for highly efficient, clear and natural sound reproduction, either in large indoor venues, such as churches, conference halls, theaters, school rooms and gyms, or in outdoors such as squares, sports grounds, open theaters and similar places.

Background art

Current sound delivery needs in large spaces, which essentially consist in achieving a considerably intelligible and natural sound reproduction, while solving all acoustic distortions mainly caused by reverberations and echoes and increased by the conformation of particular listening areas, are met by optimizing all relevant parameters, such as loudspeaker geometry and by using more and more complex loudspeakers and acoustic signal control systems.

WO-A-9533356 and US-A-6064744 disclose several embodiments of loudspeaker systems which allow to solve the above drawbacks.

A known loudspeaker system as described above, which is schematically shown in Figures 1 and 2, and generally designated by C, essentially comprises an elongate box-like cabinet B which defines a longitudinal axis, wherein a plurality of conventional loudspeakers D are disposed in adjacent positions along the longitudinal axis, as well as means T for connecting each loudspeaker to an external amplifier, not shown.

Each conventional loudspeaker D essentially comprises an outer basket-like casing H having an open end, and a sound reproducing diaphragm M, typically made of paper, cloth or an appropriate resin, which is affixed to the stepped open edge O of the casing H by an elastic suspension F, generally made of cloth or rubber. The diaphragm M is of the exponential cone type, i.e. has a generally frustoconical shape, and is connected toward the inner end to a movable cylindrical member S which is closed at this connection by a hemispherical or similar protection wall P. The movable cylindrical member S is further anchored to an elastic disc-like connection member I which is in turn anchored to the casing H at a second edge Q thereof. Furthermore, the movable member S is slideably mounted on a guide cylinder Y which is integral with a cover plate P, and passes through a central hole of the casing H and has an electric winding E that is partially embedded in a toroidal permanent magnet G, in turn supported by the cover plate P.

The above loudspeaker D, which is used in prior art loudspeaker systems, is generally of the "full range" type, with a small exponential cone diaphragm, i.e. having a diameter of 2" to 4" (about 50.1 mm to 100.2 mm) and with a ferrite permanent magnet. Such known loudspeaker has the drawback of providing a restricted angular radiation, as seen horizontally, as well as a low power-to-size ratio and has been already pushed to the uppermost limits of its development.

The above known loudspeakers are used to radiate sound in a specifically oriented beam, corresponding to the listening area, while drastically reducing resonances and the reverberation associated to a control processor for optimizing the sound response of the column.

Also, due to the directionality of currently used loudspeakers, commercially available loudspeaker columns involve a considerable risk of generating the Larsen effect, which occurs when the acoustic signal comes into and out of the same acoustic apparatus thereby generating annoying whistles, due to the need of using multiple loudspeaker systems to cover the entire large volume. A domed diaphragm loudspeaker type is known, which has the advantage of an increased power-to-size ratio as compared with exponential cone diaphragm loudspeakers. Nevertheless, this known loudspeaker type is typically used as a tweeter for high frequencies and cannot be heretofore used in full range loudspeaker columns.

A recent design of such known domed diaphragm loudspeakers assuring a full delivery range, with operating frequencies of 100 to 20,000 Hz, is particularly expensive and unfavorable for application in loudspeaker columns, where multiple parallel loudspeakers have to be used.

No loudspeaker column is up to date available, which uses domed diaphragm loudspeakers with "full range" frequencies.

Disclosure of the invention

A main object of this invention is to obviate the above drawbacks by providing a loudspeaker column with enhanced efficiency and sound reproduction quality characteristics as compared with those currently available.

A particular object is to provide a high efficiency loudspeaker column which can overcome the technological limitations associated with the use of conventional exponential cone diaphragm loudspeakers.

A further object is to reduce the Larsen effect risks due to the use of multiple parallel loudspeaker columns equipped with directional loudspeakers.

These and other objects, which will be more apparent hereinafter, are achieved by a loudspeaker column which, according to claim 1 , comprises an elongate mount defining a longitudinal axis, a plurality of loudspeakers anchored to said mount in adjacent positions along said longitudinal axis, wherein each loudspeaker has an outer housing to which, a sound reproducing diaphragm is elastically anchored, characterized in that said loudspeakers are of the type that has a cap or dome- shaped diaphragm, with at least one unbroken and continuous, substantially hemispherical central portion.

Suitably, the mount may include a box-like cabinet, wherein said loudspeakers are accommodated.

Alternatively, the mount may include an elongate plate, said loudspeakers being housed in respective cabinets, which are in turn anchored to said plate.

Preferably, the unbroken and continuous and substantially hemispherical central portion of the diaphragm is concave, with an outwardly facing concavity.

Alternatively, the unbroken and continuous and substantially hemispherical central portion of the diaphragm is convex, with an outwardly facing convexity.

While the above mentioned cap- or dome-like diaphragm loudspeakers are well known per se and commercially available, e.g. under the CIARE® trademark, they have never been used on loudspeaker columns.

The use of such loudspeakers allowed to obviate the drawbacks and overcome the technological limitations associated with prior art, thereby obtaining a surprising effect as regards clearness, depth and intelligibility of sung and spoken audio, as well as a Larsen effect attenuation.

Furthermore, a wider angular delivery aperture was obtained, as seen horizontally, as compared with loudspeaker columns that use conventional exponential frustoconical diaphragm loudspeakers.

Brief Description of the Drawings

Further features and advantages of the invention will be more clearly understood from the detailed description of a few preferred, non-exclusive embodiments of a loudspeaker system, which are described by way of a non-limiting example with the help of the annexed drawings, in which:

FIG. 1 shows an exemplary prior art loudspeaker column, using exponential cone diaphragm loudspeakers.

FIG. 2 is a front view of a conventional loudspeaker used in the prior art loudspeaker system as shown in FIG. 1 ;

FIG. 3 is a sectional view of the loudspeaker as shown in FIG. 2, as taken from a reference axial plane Ill-Ill of FIG. 4; FIG. 4 is a front view of an embodiment of a loudspeaker mounted on a loudspeaker system according to this invention;

Fig. 5 is a side view of the loudspeaker of Fig. 4;

FIG. 6 is a sectional view of the loudspeaker as shown in FIG. 5, as taken from a reference axial plane VI-VI; FIG. 7 is a front view of an alternative embodiment of a loudspeaker mounted on a loudspeaker system according to this invention;

Fig. 8 is a side view of the loudspeaker of Fig. 7;

FIG. 9 is a sectional view of the loudspeaker as shown in FIG. 8, as taken from a reference axial plane IX-IX of FIG. 7; FIG. 10 shows a first embodiment of a loudspeaker column according to the invention;

FIG. 1 1 shows a second embodiment of a loudspeaker column according to this invention;

FIG. 12 shows a third embodiment of a loudspeaker column according to the invention;

FIG. 13 shows a fourth embodiment of a loudspeaker column according to the invention;

FIG. 14 shows a fifth embodiment of a loudspeaker column according to the invention; FIG. 15 shows a sixth embodiment of a loudspeaker column according to the invention;

FIG. 16 shows a seventh embodiment of a loudspeaker column according to the invention;

FIG. 17 shows an eighth embodiment of a loudspeaker column according to the invention.

Detailed description of a few preferred embodiments

Referring to the above figures, a loudspeaker column according to the invention, overall designated by numeral 1 , comprises an elongate mount 2 defining a longitudinal axis L, a plurality of loudspeakers 3 being anchored thereto.

In the embodiment as shown in Figures 10 to 15, the mount 2 is a box-like cabinet, having an elongate, prismatic or similar shape, and made of any suitable material, such as wood, aluminum, plexiglas or the like. Also anchoring means, not shown and known to any person skilled in the art, may be positioned for possibly anchoring on the wall or on appropriate stands, or on a metal mesh or protective cloth.

Loudspeakers 3 are disposed in the cabinet 2 in a linear sequence, i.e. are aligned along the longitudinal axis L to form a "column" having the desired power and sound delivery characteristics, which depend on user and environment requirements.

Each loudspeaker has a housing or casing 4 made of a metal or synthetic material, and having a peripheral edge that defines an annular step 5, for elastic fixation thereon of a diaphragm 6 made of a laminar material, such as paper, cloth, Mylar, titanium, cadmium, resins or the like, and which forms the sound reproducing element.

The connection of the diaphragm 6 to the annular step 5 of the housing 4 is of the elastic type, e.g. uses an elastic suspension area to allow the vibration of the diaphragm 6. The diaphragm 6 is connected at its bottom to a cylindrical support 8, having a coil winding 9, through an intermediate elastic element, approximately having a glass shape.

The cylindrical support 8 may be advantageously anchored to the housing 4 by an elastic centering member 11 , at a second annular step 12 of the housing 4 and be suspended thereby.

Possibly, the cylindrical support 8 may have such a size as to be directly anchored to the elastic suspension area 7 of the diaphragm.

Finally, the cylindrical support 8 is partially embedded in an essentially cylindrical permanent magnet, which is disposed inside the support 8 and held by the cover wall 14 of the housing 4. The permanent magnet 13 is preferably of the neodymium type, but it may also be made of ferrite.

The coil winding 9 has terminals 15 for electric connection to an external amplifier, not shown. The electric signal transmitted to the amplifier, which is proportional to sound variation, will generate a varying electromagnetic field in the coil winding, adapted to interact with the constant magnetic field of the permanent magnet 13, thereby generating an electromagnetic force which will displace the cylindrical support 8, as well as the diaphragm 6, to reproduce sound by coupling with the intermediate elastic element 10.

Thanks to the geometry of its parts, the loudspeaker 3 is a full range loudspeaker, with an operating frequency of 100 Hz to 20,000 Hz. Also, each loudspeaker 3 may include a passive or active crossover filter.

According to the invention, the loudspeaker 3 is of the cap- or dome-like type, with at least the central portion 16 of the diaphragm 6 being substantially hemispherical and continuous. In the loudspeaker as shown in Figs. 5 and 6, the substantially hemispherical and continuous central portion 16 is concave, i.e. with an outwardly facing concavity.

The loudspeaker 3' as shown in Figs. 8 and 9 differs from the one of Figs. 5 and 6 essentially in that the substantially hemispherical and continuous central portion 16' of its dome or cap diaphragm 6' is convex, i.e. with an outwardly facing convexity

While these types of loudspeakers 3, 3' are already available, they have not been heretofore used or proposed for use in loudspeaker columns. The selection thereof has the purpose of overcoming the technological limitations of exponential cone diaphragm loudspeakers and is not obvious and natural for those skilled in the art.

Fig. 10 shows a loudspeaker column according to the invention having cap- shaped loudspeakers 3 (or 3'), disposed in a linear continuous sequence along the longitudinal axis L.

Conversely, Fig. 11 shows a design of a loudspeaker column 1 ', in which the loudspeakers 3 or 3' are grouped in arrays of the same number of elements (here two) having the same diameter and power, at a constant distance h from each other along the longitudinal axis L.

Fig. 12 shows a loudspeaker column which differs from the one of Fig. 11 in that the individual loudspeakers are at different distances from each other in the longitudinal direction.

Conversely, Fig. 13 shows a design of a loudspeaker system in which the loudspeakers 3, 3' have different diameters and powers and are arranged in a linear sequence but in arrays having different numbers of elements and at varying distances from each other. Fig. 14 shows a loudspeaker column in which the cabinet 2 has two crossed converging branches, to define a cross structure extending in a single plane.

Fig. 15 shows a loudspeaker column which differs from the one of Fig. 14 essentially in that the two crossed branches form dihedral angles in space. Thus, the cross structure extends in space and not in a single plane.

Fig. 16 shows a loudspeaker column in which the mount is essentially formed by an elongate plate 2. The loudspeakers 3, 3' are housed in respective cabinets 2', which are in turn affixed to the plate 2 by means of appropriate brackets.

It shall be understood that all the above embodiments are the empiric outcome of optimizing design resulting from laboratory tests.

It shall be further noted that the longitudinal axis L of the cabinet 2 wherein the loudspeakers 3, 3' are housed may be straight or curved and develop in one plane or in space.

From the foregoing disclosure, the loudspeaker column of the invention achieves the intended objects and particularly meets the efficiency and sound reproduction quality requirements associated to these apparatuses.

The loudspeaker system of the invention is susceptible of a number of changes and variants, within the inventive concept disclosed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

While the loudspeaker system has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner. The instant application is based upon and claims priority of patent application no. VI2003A000041 , filed on 03.03.2003 in Italy, the disclosure of which is hereby expressly incorporated here in reference thereto.

Claims

1. A loudspeaker column, comprising an elongate mount (2) defining a longitudinal axis (L), a plurality of loudspeakers (3, 3') anchored to said mount (2) in adjacent positions along said longitudinal axis (L), wherein each loudspeaker (3, 3') has an outer housing (4) to which a sound reproducing diaphragm (6, 6') is elastically anchored, characterized in that said loudspeakers (3, 3') are of the type having a cap or dome-shaped diaphragm (6, 6'), with at least one unbroken and continuous, substantially hemispherical central portion (16, 16').

2. Loudspeaker system as claimed in claim 1 , characterized in that said unbroken and continuous and substantially hemispherical central portion (16, 16') is concave, with an outwardly facing concavity.

3. Loudspeaker system as claimed in claim 1 , characterized in that said unbroken and continuous and substantially hemispherical central portion (16, 16') is convex, with an outwardly facing convexity.

4. Loudspeaker system as claimed in claim 1 , characterized in that each loudspeaker (3, 3') includes a movable cylindrical member (8) which is elastically anchored to said housing (4) and to the diaphragm (6, 6') and has a coil winding (9) for interaction with a permanent magnet (13).

5. Loudspeaker system as claimed in claim 4, characterized in that said permanent magnet (13) is of the ferrite or neodymium or cadmium type.

6. Loudspeaker system as claimed in claim 1 , characterized in that said loudspeaker (3, 3') is a full range loudspeaker, with an operating frequency of 100 Hz to 20,000 Hz.

7. Loudspeaker system as claimed in claim 1 , characterized in that each loudspeaker (3, 3') includes a passive or active crossover filter.

8. Loudspeaker system as claimed in claim 1 , characterized in that said mount comprises a box-like cabinet (2), in which said loudspeakers (3, 3') are accommodated.

9. Loudspeaker system as claimed in claim 1 , characterized in that said mount comprises an elongate plate (2'), said loudspeakers (3, 3') being accommodated in respective cabinets (2"), which are in turn anchored to said plate (2').

10. Loudspeaker system as claimed in claim 1, characterized in that said loudspeakers (3, 3') are arranged in a linear continuous sequence and have the same diameter and power.

11. Loudspeaker system as claimed in claim 1 , characterized in that said loudspeakers (3, 3') are arranged in a linear continuous sequence and have different diameters and powers.

12. Loudspeaker system as claimed in claim 1 , characterized in that said loudspeakers (3, 3') are arranged in a linear continuous sequence in arrays composed of different numbers of elements and disposed at a substantially constant distance from each other.

13. Loudspeaker system as claimed in claim 1 , characterized in that said loudspeakers (3, 3') are arranged in a linear continuous sequence in arrays composed of different numbers of elements and disposed at a varying distance from each other.

14. Loudspeaker system as claimed in claim 1 , characterized in that said loudspeakers (3, 3') have the same diameter and power or different diameters and powers in combination.

15. Loudspeaker system as claimed in claim 1 , characterized in that the longitudinal axis of said mount (2) is substantially straight.

16. Loudspeaker system as claimed in claim 1 , characterized in that the longitudinal axis of said mount (2) is curvilinear in one plane or in space.

17. Loudspeaker system as claimed in claim 1 , characterized in that said mount comprises at least two crossed converging branches, to define a cross structure.

18. Loudspeaker system as claimed in claim 17, characterized in that said crossed branches form dihedral angles in space.