EP0714590B1

EP0714590B1 - Loudspeaker

Info

Publication number: EP0714590B1
Application number: EP94923018A
Authority: EP
Inventors: Henry Azima
Original assignee: Centralforce Ltd
Current assignee: Centralforce Ltd
Priority date: 1993-08-20
Filing date: 1994-08-08
Publication date: 1997-01-22
Anticipated expiration: 2014-08-08
Also published as: WO1995006397A1; HK1000991A1; GB9317345D0; DE69401593D1; CN1129510A; AU7272694A; DK0714590T3; DE69401593T2; CA2165327A1; EP0714590A1

Abstract

A loudspeaker comprises an enclosure (2) having a baffle (7) surrounding a drive unit (4), characterised by means, e.g. columns or pillars (3) mounting the drive unit (4) in the enclosure (2) remote from the baffle (7).

Description

TECHNICAL FIELD

The invention relates to loudspeakers and more particularly to loudspeakers of the kind comprising a box-like enclosure, which may be cuboid in shape or otherwise, housing one or more loudspeaker drive units.
It is an object of the invention to provide an improved loudspeaker. More particularly it is an object of the invention to provide a loudspeaker in which its baffle, on which it is conventional to mount the drive units, is de-coupled from at least one of the drive units.
Such de-coupling is desirable to prevent audible distortions due to unintended exitation of the baffle or due to unintended exitation of one drive unit, e.g. a tweeter, by another drive unit e.g. a mid/bass range drive unit, mounted on the same baffle.
De-coupling should not, however, be such as to hinder the direct coupling of the drive units via the enclosure to the stand, shelf or floor on which the loudspeaker is supported.

BACKGROUND ART

To avoid such problems it has been suggested to mount the loudspeaker tweeter in a separate enclosure, which may be physically separated from the associated enclosure housing mid range and base drive units. Such an arrangement involves additional expense in construction and is not always possible for example for considerations of available space.

DISCLOSURE OF INVENTION

Accordingly the present invention provides a loudspeaker enclosure having a baffle surrounding a drive unit, comprising means mounting the drive unit in the enclosure remote from the baffle. The baffle may have a drive unit, e.g. a tweeter, directly mounted thereon, with the associated mid range and/or base drive unit(s) mounted remotely from the baffle. Preferably the sole connection between one drive unit and the baffle is by way of resilient sealing means, e.g. a gasket.
Where the enclosure is a generally conventional cuboid box-shape, one of the drive units may be mounted on the rear surface of the enclosure. The said remotely mounted drive unit may be mounted on one or more, preferably several, pillars or columns projecting across the enclosure from its rear. Preferably the pillars or columns are tapered so that they have the effect of assisting in breaking up standing waves within the enclosure. The pillars or columns may be integral with the rear wall of the enclosure and may, for example, be moulded from a plastics material e.g. mica-filled polypropylene.
The tweeter may be mounted in position in the enclosure by trapping it between the baffle and one or more columns or pillars so that no separate fasteners are used.
At least one of the pillars or columns may also be used to support the baffle.

BRIEF DESCRIPTION OF DRAWINGS

The invention is diagrammatically illustrated, by way of example, in the accompanying drawings in which:-

Figure 1 is an exploded sectional side view of a loudspeaker made in accordance with the present invention;
Figure 2 is a sectional side view of the loudspeaker of Figure 1, and
Figure 3 shows, to a large scale, detail A of Figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION

In the drawings a loudspeaker comprises an enclosure consisting of a cuboid box-like cabinet 2 closed by a baffle 7, both of which are moulded from a plastics material such as mica-filled polypropylene. The cabinet is formed internally with a series, e.g. four, of integral tapered pillars or columns 3 which project across the enclosure from its rear 9 and so that their free ends 12 are disposed in the vicinity of the front edge 11 of the enclosure 2. The tapered shape of the pillars or columns 3 is useful in tending to break-up standing waves in the enclosure. A low frequency drive unit 4 is mounted on the columns 3 by fasteners, e.g. screws 16 so as to be surrounded by, but spaced from, an aperture 13 in the baffle 7. A resilient seal 5 is interposed between the drive unit 4 and the aperture 13 in the baffle 7 so that the drive unit 4 is decoupled from the baffle. Between the respective edges 10,11 of the baffle 7 and the cabinet 2 is interposed a resilient de-coupling seal 6 so that the baffle is decoupled from the enclosure.
A high frequency drive unit 8 is directly mounted to close an aperture 14 in the baffle 7 by means of fasteners, e.g. screws 15.
An electronic cross-over network 1 is mounted on the rear face 9 of the enclosure.

INDUSTRIAL APPLICABILITY

The arrangement described above not only produces a loudspeaker in which the main drive unit is acoustically de-coupled from the baffle but also has the advantage of easy assembly. Thus with the cabinet laid on its back, the speaker components can be dropped into place, perhaps robotically. Also some testing of the loudspeaker can be carried out before the baffle is attached.
Mounting the low frequency drive unit directly onto the rear baffle of the enclosure ensures good coupling to the seat of the cabinet i.e. a stand or shelf, which is helpful in the extraction of the full dynamics of the speaker.
Mounting the high frequency drive unit on the front baffle ensures a rigid coupling to the stand or shelf. Also the fact that the paths for the two drive units are somewhat independent ensures at least one order of isolation between the high frequency and low frequency units while each is rigidly coupled to the floor.
With or without a high frequency drive unit, the isolation of the low frequency drive unit from the front baffle reduces box colouration due to acoustic radiation from the baffle board.
The loudspeaker described above can thus be of improved performance compared to a speaker in which all of the drive units are mounted on a common baffle.

Claims

A loudspeaker comprising an enclosure (2) having a baffle (7) and surrounding a drive unit (4) characterised by means (6) decoupling the baffle from the enclosure and by means (3,5) mounting the drive unit (4) to the enclosure (2) remote from the baffle (7) such that the drive unit (4) is decoupled from the baffle (7).
A loudspeaker according to claim 1, characterised in that the drive unit (4) is a mid range and/or low frequency drive unit and by a high frequency drive unit (8) directly mounted on the baffle (7).
A loudspeaker according to claim 1 or claim 2, characterised by resilient sealing means (5) which seals the drive unit to the baffle while maintaining one decoupled from the other.
A loudspeaker according to any preceding claim, characterised in that the enclosure (2) is of box-shape, in that the baffle (7) forms the front of the enclosure, in that the enclosure has a rear (9) opposing the front and in that the drive unit (4) is mounted on the rear (9) of the enclosure.
A loudspeaker according to claim 4, characterised in that the drive unit (4) is mounted on at least one pillar or column (3) projecting across the enclosure from its rear (9).
A loudspeaker according to claim 5, characterised in that the or each pillar or column (3) is tapered along its length.
A loudspeaker according to claim 5 or claim 6, characterised in that the or each pillar or column (3) is integral with the rear (9) of the enclosure (2).
A loudspeaker according to any one of claims 2 to 7, characterised in that the high frequency drive unit (8) is mounted in position in the enclosure by entrapment between the baffle (7) and one or more columns or pillars (3).
A loudspeaker according to any preceding claim, characterised in that the baffle (7) is supported by one or more pillars or columns (3).
A loudspeaker according to any preceding claim, characterised in that the baffle (7) is sealed to, and decoupled from, the enclosure (2) at their respective edges (10,11) by a resilient seal (6).
A loudspeaker according to any preceding claim, characterised in that the enclosure (2) and/or the baffle (7) are moulded from a plastics material.