THIN FULL RANGE SPEAKER SYSTEM

SYSTEME DE HAUT-PARLEURS MINCE COUVRANT TOUTE LA GAMME

English Abstract

A thin full range speaker system has a planar diaphragm and a coaxial
electromagnetic driver. Its light weight and compact size make it
suitable to be used as a wall-mounted or a ceiling-mounted speaker system.

French Abstract

Système de haut-parleurs à amplitude maximale, à diaphragme planaire et commande électromagnétique coaxiale convenant, par son faible poids et son aspect compact, pour une installation au mur ou au plafond.

Claims

The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A thin full range speaker system comprising:
an electromagnetic driver means; said driver means having a voice coil
bobbin affixed to a front planar diaphragm; said planar diaphragm is
suspended from an encircled frame of a system enclosure by a layer of
foam plastic rubber or similar material; said voice coil bobbin having a
large enough diameter or a bell-shaped mouth to accept a coaxial high
frequency tweeter; said electromagnetic driver having a small frame to
support two dampers, one normal damper and an auxiliary centering spider;
said electromagnetic driver is fixed to a system enclosure by fastening
the said frame to a mechanical structure inside the system enclosure;
said front planar diaphragm having an opening into which the voice coil
bobbin is fixed; and said coaxial tweeter radiates high frequency sound
waves through this front planar diaphragm opening.
2. As defined in claim 1, said voice coil bobbin means having a
cylindrical ring device at the front end of the voice coil bobbin, as
part of a snap-in assembly; there is a flange at the inner end of the
cylindrical ring device in contact with and supporting the inner surface
of the front planar diaphragm; at the outer end of the said cylindrical
ring device, there is a clamping means, a snap-in ring disc pressing the
outer surface of the front planar diaphragm firmly; said cylindrical ring
device and ring disc together form a snap-in structure.
3. As defined in claim 1, said system enclosure is a one piece, hollow
cylinder-shaped structure having a protruding circular shoulder for the
said front planar diaphragm to fit into and to support the said coaxial
electromagnetic driver.
4. As defined in claim 3, said system enclosure having metal sheet
interior wall as a skeleton; the exterior wall of the said metal skeleton
is covered with foam-plastic or similar material; at least the recessed
region of the metal skeleton is solid and bare to allow direct contact
with the surrounding air to facilitate heat dissipation.
5. As defined in claim 1, said coaxial transducer comprising a midrange
cone speaker.

Description

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This invention relates to a full range thin speaker system which is
compact, light and suitable for wall or ceiling mounting providing high-
fidelity sound reproduction.
Generally, conventional full range speaker systems consisting of at least
a tweeter and a woofer enclosed in a box are bulky and heavy. When a
speaker system is to be mounted against a wall, a bulky conventional cone
speaker system is impractical. Comparatively, it is easier to make a flat
type speaker system thin and is suitable for wall mounting applications.
A flat speaker typically includes a planar diaphragm instead of the cone-
shaped diaphragm of a cone speaker. The planar diaphragm is constructed
from light, rigid material, such as foam polystyrene. Behind the planar
diaphragm, there is at least one electromagnetic driver. In accordance
with acoustic principle, the frequency range of a foam-plastic planar
diaphragm is a function of its density, thickness and diameter. In order
to reproduce a full range sound spectrum, a planar diaphragm has to be
divided into a low frequency region and a high frequency region. The low
frequency region has a larger diameter and is thinner than the high
frequency region, and each region has its own driver. This complicates
the system construction and increases manufacturing costs.
As is well known, a coaxial cone-speaker transducer is popular as a
compact, full range speaker transducer. In addition, the manufacturing
process of a conventional cone speaker is mature.
The first objective of this invention is to provide a speaker system
which is as thin as a flat speaker system with the advantages of a
conventional coaxial speaker system. Another objective of this invention
is to provide a speaker system structure which is easy to build. This
invention integrates the advantages of a planar speaker and a coaxial
conical speaker.
The preferred embodiments of the present invention will be described in
greater detail with reference to the accompanying drawings.
A brief description of the drawings.
Fig.l is a sectional view of an embodiment of the present invention;
Fig.2 is a sectional view of the embodiment of Fig.l, showing the beam
structure;
Fig.3 is another sectional view of Fig.l, showing the air pathway of a
silencer apparatus;
Fig.4 depicts the sub-assembly modules of the embodiment shown in Fig.l;

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Fig.5 is a sectional view of the fixing structure joining the voice
bobbin and the front planar diaphragm;
Fig.6 is a sectional view of an one-piece embodiment of the system
enclosure of the invention;
Fig.7 is a sectional view of another embodiment of the system enclosure.
Referring now to Fig.l, a coaxial electromagnetic driver having a magnet
2, a voice coil(not shown), and a voice coil bobbin 3, a tweeter 10 and a
frame 1 supporting two dampers 12, 13; the damper 12 is a normal damper;
the damper 13 is an auxiliary centering means to keep the voice bobbin in
position; the frame and thus the whole electromagnetic driver is fastened
to beams 26, 27; beams 26, 27 are sited on an internal shoulder structure
6 of the system enclosure 4; the shoulder structure 6 is also supporting
a silencer apparatus 50 at rear side and a planar diaphrag~ 7 at the
front side; the rear side cover 25 having an extrusion means 25a to
protect air outlet 24 from being blocked when mounted flat against a wall;
the silencer apparatus has been explained in an application for another
invention~serial number 2,174,455) of the inventor, and will not be
repeated here.
In Fig.2 and Fig.4, beam structure 26, 27 is shown. The frame 1 of an
electromagnetic driver assembly 40 is fastened to said beam structure 26,
27. The front planar diaphragm 7 and the suspension 8 are locked into its
position by a frame 9. The suspension 8 is made of foam rubber or similar
material. ~hen the frame 1 of the electromagnetic driver 40 is fastened
to beams 26, 27, the front edge of the voice coil bobbin 3 will fit into
the opening of the front planar diaphragm 7. Snap-in disc ring lla snaps
into the clamping means 11, thus completing the assembly of the
electromagnetic driver 40 and the system enclosure assembly 30.
Fig.5 is an enlarged sectional view of a snap-in clamping means. In Fig.3
an air pathway, 15-22, of a silencer apparatus is shown. The rearward
sound waves will be absorbed and decreased by the silencer apparatus when
passing through 15-22.
In Fig.6, a sectional view of an one piece system enclosure is shown.
Compared with the system enclosure shown in Fig.l, the manufacturing and
assembly costs can be lower. In Fig.7, another embodiment of a system
enclosure having a metal skeleton 4a and heat dissipation surface 4b is
shown. The metal skeleton can be made of a punched metal sheet or woven

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metal to take advantage of its lighter weight. A foam plastic covering 4c
is used for protection and vibration absorbing purposes. Since the
present invention has an intrinsic system enclosure, no front baffle
board is needed for speaker transducer mounting, usually necessary for a
conventional cone-speaker system. On the contrary, the front planar
diaphragm of the present invention is made of foam-polystyrene or similar
material, which is very light compared to the front baffle board of a
conventional speaker box. Thus the weight of the present invention
speaker system is much less than a conventional cone-speaker system.
Full-range sound response is easier to design and more economical to
manufacture than a simple flat speaker system. The compact size, light
weight, full-range acoustic response and easy of assembly are the
features of the present invention.

Representative Drawing