DE29501028U1 - Loss factor reducing loudspeaker enclosure - Google Patents

Description

Description

1.1 Description of the invention

Loss factor reducing loudspeaker cabinet

1.2 General

The invention relates to a loss factor-reducing housing for loudspeaker chassis, which can be used for sound reinforcement purposes.

1.3 State of the art

To accommodate loudspeaker chassis, enclosures are generally used in which excessive losses occur due to leaks in the connection plate terminals and in the cutouts for the handles.

In addition, speaker walls that are not sufficiently stiffened are stimulated to bending vibrations. In conjunction with cabinet walls that are capable of bending vibrations, excessive energy losses occur (QL factor), which influence the sound radiation of the loudspeaker chassis so strongly that major sound disadvantages occur.

Furthermore, energy losses occur due to "standing waves" inside a speaker cabinet.

1.4 Features

The object underlying the invention is to define a loudspeaker housing that reduces the loss factor and has only minimal energy losses even with higher electrical power. According to the invention, this is achieved by the following features:

Günter Strauß - loss factor reducing loudspeaker cabinet

1.4.1 Sealing boxes

The loss factor-reducing loudspeaker box housing contains three sealing boxes, which are installed inside the box behind the recesses for the handles and the connection plate terminals in such a way that the losses due to sound escaping to the outside are greatly reduced. This is particularly enhanced by the fact that additional insulating materials are inserted inside the boxes between the metal parts of the handles or the connection plate terminals and the wood of the sealing boxes.

The sealing box, which is attached to the box wall behind the connection plate terminal, contains at least two holes for the cables. The cables are secured on both sides with an airtight adhesive so that the possible loss of sound energy is minimized.

1.4.2 Stiffening strips

The wooden strips to be inserted into the interior of the loudspeaker box housing, which consist of 18 mm thick and 22 mm thick plywood, are inserted into the housing in the form of strip rings, diagonal strips and space strips in such a way that the possible bending vibrations of the housing walls are minimized. The dimensions of the strips are determined in such a way that the greatest possible stability is guaranteed with minimal space displacement. These measures lead to a further reduction in the loss factor.

The strip rings and the diagonal strips are inserted into the loudspeaker cabinet in a preferred direction depending on the wood structure so that the bending moment forces (Mb) are minimized.

Strip rings: Due to a ring-shaped or frame-shaped arrangement of the strips on the inner walls of the box, where 4 sides form a ring, the stabilizing factor of the individual strips when pressed against the other strips of the ring is considerably higher than with individual strips. In every loss factor-reducing loudspeaker box housing, several of these strip rings must be inserted, namely at the points on the box walls where there is an increased energy loss due to resonance and

Günter Strauß - loss factor reducing loudspeaker cabinet

Bending forces are to be measured. For structural reasons, a closed ring cannot always be realized; here the strips are closed as far as possible to form a ring and only the most necessary places are left free, e.g. the sawn-out openings on the baffle.

Diagonal strips: In order to achieve not only good bending stability of the walls, but also a division of the area into frequency-different resonance sub-areas, which avoid an overall resonance of larger areas, diagonal strips of different lengths are applied to the wall sections left free by the ring strips.

Space struts: In order to further minimize the energetic impact of the pressure waves on the box housing, space struts are fitted with a press fit between the opposite walls or between an existing space bar and a box wall. They never press directly on a box wall, but rather on a place where a force distribution is possible vertically to the direction of attachment. These are bars of bar rings or sealing boxes. The space struts are attached to them at right angles.

As far as structurally possible, the individual space struts are connected to each other in order to minimize their bending moment forces.

1.4.3 Sound coupling barrier layers

There are several transitions between different materials and transitions between active and passive elements that significantly increase the loss factor of a loudspeaker box if they are not separated energetically by suitable measures. These sound coupling barrier layers are needed in precisely those places where a high level of air density is also required in the loudspeaker box housing that reduces the loss factor. Therefore, a special elastic mass is pressed in between the sound transducer and the front panel, between the handles and the side walls, between the connection plate terminal and the rear panel and between all other metal parts and the wood underneath, which acts as both a sound coupling barrier layer and an air-tight element.
The optimal layer thickness in the pressed state is between µm and 1 mm.

Günter Strauß - loss factor reducing loudspeaker cabinet

1.4.4 Resonance damping

By attaching a nubbed foam to the inner walls of the loudspeaker boxes, the sound emission through the outer walls is reduced in a frequency-selective manner by different refraction angles at the transition from the soft to the hard zone, so that sound absorption of the sound velocity particles in the area of the tapering nub tips leads to a further reduction in the loss factor.

By appropriately damping the room struts, a frequency-selective reduction in the standing wave modes occurs, so that the resonance-related energy absorption of the sound particles is minimized. At the same time, the special type of damping of the room struts reduces the frequency-dependent transmission of sound energy to the outer walls.

Günter Strauß - loss factor reducing loudspeaker cabinet

Utility model application for
Loss factor reducing loudspeaker cabinet

Günter Strauss

King's Gate. 55a

34119 Kassel

24.1.1995 Table of contents

Description 3

1.1 Description of the invention 3

1.2 General 3

1.3 State of the art 3

1.4 Features 3

1.4.1 Sealing boxes 4

1.4.2 Stiffening strips 4

1.4.3 Sound coupling barrier layers 5

1.4.4 Resonance damping 6

Protection claims 7

2.1 Loss factor reducing loudspeaker cabinet ... 7

2.1.1 Sealing boxes 7

2.1.2 Reinforcing strips 7

2.1.3 Sound coupling barrier layers 8

2.1.4 Resonance damping 8

2.2 Sealing boxes in box interiors 8

2.3 Groin rings in box interiors 9

2.4 Diagonal strips in box interiors 9

2.5 Space braces in box interiors 9

2.6 Sound coupling barrier layers in box interiors ... 10 2.6.1 Sound transducers 10

2.6.2 Handles . . . *'.". .*...".. &Ggr;7. .". ."V. 10

2.6.3 Connection plate terminals 10

2.7 Resonance damping in speaker interiors 10

2.7.1 Interior walls 10

2.7.2 Space struts 10

Drawings 11

3.1 Principle of strip application 11

3.2 Groin rings & space struts 12

3.3 Principle of Diagonal Loistoii 13

3.4 Section of a sound coupling barrier layer 14

Günter Strauß - loss factor reducing loudspeaker cabinet

Claims (5)

Protection claims 2.1 Loss factor reducing loudspeaker cabinet ·* · ♦· ·
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· · · · φ · *
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» · * · * The loss factor-reducing loudspeaker box housing for accommodating sound transducers that preferentially radiate low frequency ranges is characterized by the following features: 2.1.1 Sealing boxes The loss factor-reducing loudspeaker box housing contains three sealing boxes, which are installed inside the box behind the recesses for the handles and the connection plate terminals in such a way that the losses caused by sound escaping to the outside are greatly reduced. In addition, insulating materials are installed inside the boxes between the metal parts of the handles and the connection plate terminals and the wood of the sealing boxes. The sealing box, which is attached to the box wall behind the connection plate terminal, contains at least two holes for the cables. The cables are attached on both sides with an airtight adhesive. 2.1.2 Stiffening strips Inside the loudspeaker box housing, wooden strips made of 18 mm thick and 22 mm thick plywood are attached in the form of strip rings, diagonal strips and space strips . (Mounting method: see drawing) Strip rings: Strip rings are attached to the places on the box walls where an increased energy loss is measurable, so that a strip is attached to each of the 4 inner walls, which together form a ring. There are at least 2 horizontal strip rings. These connect the baffle to the rear wall via the side walls. And there are at least 2 vertical strip rings. These connect. firstly the top side to the bottom side via the side walls, and secondly the top side to the bottom side via the front and rear. The continuation of the Günter Strauß - Loss factor reducing loudspeaker box housing 7 Vertical strip rings are interrupted at the openings in the baffle and the sealing boxes. (Strip rings: See drawing 2)
The strip rings are attached to the inner walls in such a way that the gluing direction of the plywood runs at right angles to the wall. (Gluing direction: see drawing 1) Diagonal strips: Diagonal strips made of 18 mm and 22 mm thick plywood are glued onto all wall surfaces left free by strip rings. (Diagonal strips: See drawing 3) Space bars: The opposite box walls are connected to each other by space bars, which are each attached to the bars of the bar rings at a 90° angle. A space bar connects the sealing boxes of the handle shells (in the side walls) to each other. (Attachment: see drawing 1, arrangement: see drawing 2) 2.1. 3 sound coupling barrier layers An elastic mass is inserted between the sound transducer and the baffle, between the handles and the side walls, between the connection plate terminal and the rear wall of the box, the layer thickness of which is between |mm and lmm when pressed. (Sound coupling barrier layer: see drawing 4) 2.1. 4 Resonance damping A 4cm thick convoluted foam is applied to all inner walls of the loss factor-reducing loudspeaker box housing. The ratio of flesh to convoluted foam is 1:3cm.
All space struts are wrapped with damping materials. 2.2 Sealing boxes in box interiors Sealing boxes cover the connection plate terminals and the handles in an airtight manner inside a box. The free space in the sealing boxes is filled with insulating materials. Günter Strauß - Loss factor reducing loudspeaker cabinet 8 The sealing box, which is located behind the connection plate which is attached to the box wall, contains at least two holes for the cables. The cables are attached on both sides with an airtight adhesive. 2.3 Groin rings in box interiors At the points on the box walls where increased energy loss is measurable, strip rings are attached in such a way that a strip 18mm wide and 22mm thick is attached to each of the 4 inner walls, which together form a ring. There are horizontal strip rings. These connect the baffle to the rear wall via the side walls. And there are vertical strip rings. These connect the top to the bottom via the side walls, and the top to the bottom via the front and rear. The vertical strip rings are interrupted at the openings in the baffle and at the sealing boxes. (Strip rings: see drawing 2)
The strip rings are attached to the inner walls in such a way that the gluing direction of the plywood runs at right angles to the wall. (Application: See drawing 1) 2.4 Diagonal strips in box interiors On all free, inner wall surfaces, strips made of 18 mm and 22 mm thick plywood are glued diagonally. (Diagonal strips: see drawing 3) 2. 5 Space struts in box interiors The opposite box walls are connected to each other by space strips, which are each attached to strips or sealing boxes at a 90° angle. (Attachment: see drawing 1, arrangement see drawing 2) Günter Strauß - loss factor reducing loudspeaker cabinet 2.6 Sound coupling barrier layers in box interiors 2.6.1 Transducer An elastic mass is inserted between the sound transducer and the baffle, the thickness of which in the pressed state is between ^mm and lmm . (See drawing 4) 2.6.2 Handles An elastic mass is inserted between the handle shells and the side walls, the thickness of which in the pressed state is between and lmm. 2.6.3 Connection plate terminals An elastic mass is inserted between the connection plate terminal and the rear wall of the box, the layer thickness of which in the pressed state is between ^mm and lmm . 2.7 Resonance damping in speaker interiors 2.7.1 Interior walls A 4cm thick convoluted foam is applied to all interior walls. The ratio of flesh to convoluted foam is 1:3cm. 2.7.2 Space struts All space struts are wrapped with damping materials. Günter Strauß - loss factor reducing loudspeaker cabinet