Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to loudspeaker cabinets.
It is known to form a loudspeaker cabinet having at least one recess
in a sidewall thereof for receiving a loudspeaker.
Known loudspeaker cabinets predominantly comprise laminated sheets -
of particle board assembled by the folding method.
It is also known to manufacture small one piece loudspeaker cabinets
of various synthetic materials, or metals. But this manufacturing technique
has not proved effective in connection with the production of larger loud-
speaker cabinets on account of the high costs of molding and material.
In accordance with the present invention there is provided a loud-
speaker cabinet, consisting of side walls, a top wall and a bottom wall, and
having at least one opening in one of said side walls for the reception of a
loudspeaker, with the loudspeaker received in said opening being covered,
characterized in that the cabinet consists of hard polystyrene foam and that a
textile fabric in hose form has been pulled over the side walls of cabinet.
The present invention may be used to provide a loudspeaker cabinet
which is substantially cheaper and more durable than the loudspeaker cabinets
hitherto known. -~
The invention may also be used to provide loudspeaker cabinets of
~0 all sizes which are substantially cheaper than similar loudspeaker cabinets
made of laminated sheets of particle board according to the folding method or
which are manufactuTed in one piece.
The textile hose fabric, drawn over the cabinet, covers scratches and
indentations which may be formed on the surface of the cabinet by being always
stretched flat over the loudspeaker cabinet and covering and making invisihle
the scratches and indentations. This applies not only to damage caused to
the loudspeaker in use, but also to irregularities on the surface of the
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cabinet caused by the manufacturing process. Such irregularities are, for
instance, air-nozzle, weft and extractor marks.
No special casing is required to cover the acoustic baffle, since
the latter is likewise covered by the textile hose fabric. This leads to a
further reduction in the cost of the loudspeaker cabinet, for it is possible
thereby to save both additional material and expensive additional working
steps.
For a better understanding of the invention, and to show how the
same may be carried into effect, reference will now be made, by way of example,
to the accompanying drawing in which:
Figure 1 is a perspective view of a textile hose fabric; `
Figure 2 is a perspective view of a loudspeaker cabinet; and
Figure 3 is a sectional view of an acoustic baffle.
The considerations that follow led to the invention. The production
of a loudspeaker cabinet from a foamable material was formerly not possible, -
since the surface of the cabinet could be easily damaged due to its softness:
blows or act of other kind resulted in indentations, depressions, or scratches
on the surface which impaired the esthetic effect of those cabinets or boxes.
On the other hand, the surfaces also had, as result of the manufacturing pro-
2Q cess"irregularities that likewise impaired the esthetic effect. As it has
already been said before, those irregularities result from air-nozzle, weft
and extraction marks produced by the manufacturing process. In a loudspeaker ;
cabinet made of hard polystyrene foam, it is not possible to prevent such ,`-
irregularities produced in the manufacture by polishing and then lacquering or
covering with a veneer the surface of the housing, since polystyrene foam is
affected or decomposed by most solvents found in paints and adhesives.
The illustrated loudspeaker cabinet is p~oduced from polystyrene foam
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by a hard foamlng and is sheathed with a textile hose fabric drawn over the
cabinet, like a stocking. The fabric, which is stretched tight and flat over
all four sidewalls of the loudspeaker cabinet and consists of sound-pervious
material, covers the irregularities resulting from the manufacture of the
cabinet and also surface indentations made later.
Figure 1 illustrates a cabinet 1 made of polystyrene foam and having
five outer walls. The front wall of the cabinet has, for instance, recesses 3,
4 and 5 in which the individual loudspeakers are subsequently introduced. On
the bottom of the cabinet 1 is preferably provided a groove 6 for subsequent
insertion of the electric connecting cable. Behind the recesses 3, 4 and 5 can
be seen braces or reinforcements 7. The cabinet 1 is open at the rear. The
rear opening is later preferably closed by a snugly embedded and secured sheet
of particle board. It is also conceivable to produce the cabinet l in a manner
such as to be closed at the rear and open at the front. In this case, an
acoustic baffle having the individual loudspeakers is later inserted in the
front opening.
For producing a loudspeaker cabinet constructed in the manner pre-
viously described, expandable polystyrene of a minimum density of from about
100 to 120 g/lt is foamed. At the same time, denser polystyrene beads are not
so str,ongly foamed as is usual. As a result there is taken from the manufactur-
ing mold a loudspeaker cabinet that is so strong that, for instance, the surface
thereof can be indented barely 1 mm deep with a finger nail. The cabinet thus
obtained is extremely stable and of great loading capacity. The mold used in
the manufacture is advantageously cheaper than molds that have hitherto been
used in the processing of other foamable materials.
To cover the already mentioned irregularities resulting during
manufacture, after inserting the loudspeaker and/or the rear wall, or after
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inserting the acoustic baffle that includes the loudspeakers, a hose-like textile
fabric 8 is drawn over the sidewalls of the cabinet l. The textile hose fabric
preferably consists of an extremely sound-pervious material such as smooth plas-
tic fibers. The mold used in the manufacture or in the foaming is preferably
shaped in a manner such that the edges of the loudspeaker cabinet are not sharp ;
but rounded. Prior to applying the textile hose fabric, the sidewalls are pre-
ferably coated with a paint that matches the color of the textile hose fabric
and does not affect the polystyrene. When using a black textile hose fabric 8,
the sidewalls of the cabinet l are coated, for example, with a black rubproof
paint. After the textile hose fabric has been snugly drawn over the sidewalls~
the fabric is secured in suitable manner such as by clamping to the upper side
and to the lower side of the cabinet. The upper and lower sides can be covered
with plastic caps that are economically produced and of a color and surface ~-
grain adapted to the textile hose fabric.
In a cabinet produced in the above described manner with an open
front, there is inserted in the front opening an acoustic baffle having a
single loudspeaker. Hitherto, acoustic baffles have consisted in part of
particle board, metal, or plastic sheets. Those known acoustic baffles have
recesses in which the frames of the loudspeakers are inserted with metal
~0 baskets made of sheet metal or formed by casting. In the case of the illustrated
loudspeaker cabinet, on the other hand, the acoustic baffle and the loudspeaker
baskets are made in one piece and from one material. The acoustic baffle 9
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shown in Figure 3 has, in predetermined locations, depressions lO, ll and 12
which correspond to the baskets of the individual loudspeakers. An opening is
provided at the lower end of each depression. After the production of the
acoustic baffle from one piece, the magnets 13, 14 and 15 and the diaphragms
16, 17 and 18 are mounted. Compared to the hitherto conventional assembly of i
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separate loudspeaker frames in recesses provided in acoustic baffles, the
acoustic baffle formed of one piece as described above has the following ad-
vantages. First, whereas several molds were needed for producing the known
acoustic baffles namely, one mold for the acoustic baffle and additional mold
for the individual loudspeaker baskets, one single mold is to be used in the
manufacture of the acousti.c baffle shown in Figure 3. Second, in the acoustic
baffle shown in Figure 3 all the loudspeakers are advan~ageously assembled in
one manufacturing step, whereas in the known acoustic baffles the loudspeakers
themselves are first assembled and then must be inserted in the acoustic baf-
fle: the eliminated manufacturing step results in a reduction in production
costs. Third, in the acoustic baffle shown in Figure 3 the connection between
the loudspeaker frame and the acoustic baffle is especially durable and compact, ~
since it consists of one piece. ;
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