Abstract: The invention relates to a planar loudspeaker comprising a light, thin soundboard (2) which may be energized to produce multiply-reflected bending waves, a surrounding frame (3) holding the soundboard (2) in an articulated, shear-resistant manner; at least one driver (6, 7, 9, 10) connected to the soundboard (2) to energize the soundboard (2); and at least one bridge (13, 16, 18, 20, 22, 25), rigidly connecting the at least one driver (6, 7, 9, 10) to the frame (3), wherein the bridge or at least one of the bridges (13, 16, 18, 20, 22, 25) is connected to the damping board (14).

Abstract: The invention relates to the embodiment of so-called panel loudspeakers working according to the bending wave principle. Said panels are generally formed by a panel (11), at least one driver (12) and a frame (13), the panel (11) being connected to the frame (13). In order to achieve appropriate bending wave induction in the panel (11), very complicated assessments must be made in order to determine the corresponding positioning areas (15) in which the driver (12) excites the panel (11) or is connected to the latter. Furthermore, the size of the panels (11) can change considerably depending on the application so that assessments must only be made repeatedly in the case of panels that can be easily modified. The invention aims at providing general positioning areas (15) for the driver (12) in or on the panels (11) so that no further assessments need to be carried out regarding the positioning area (15).

Abstract: The invention relates to a system with multi-mode radiator panels used to reproduce sound. The multi-mode radiator panels include at least one driver, a core layer and two cover layers connected to the core layer. The panels are typically mounted in a frame with attachments providing a connection between the frame and the unit formed of the core layer and the cover layers. To protect the system against overload and damage, the entire driver electronics is housed in a hermetically sealed air space located between the frame, the core layer and the attachments. The driver electronics includes a power amplifier powered by low-voltage power supply. The voltage supply may be buffered by a battery to keep the average power supplied to the electronics small, while still being able to reproduce infrequently occurring peak power events.

Abstract: The invention relates to an electromagnetic driver comprising a soft magnetic core in the form of an E with three legs and a back, an alternating field driver, magnetically coupled to the soft magnetic core, for generating an alternating magnetic field in the soft magnetic core, depending upon a sound signal, a constant field driver magnetically coupled to the soft magnetic core for generation of a constant magnetic field in the soft magnetic core, a soft magnetic element for coupling to the plate of the planar diaphragm loudspeaker, lying opposite the back and magnetically closing the legs across at least one small induction gap, whereby the constant field and the alternating field are asymmetrically superimposed such that a resulting force, or a resulting torque on the soft magnetic element, is proportional to the sound signal.

Abstract: The invention concerns the embodiment of panel loudspeakers working according to the bending wave principle. Said loudspeakers are generally formed by at least one acoustic panel (11) and at least one driver (12), the driver (12) being connected to the acoustic panel (11). When such acoustic panels (11) are used for reproducing low frequency audio signals, the acoustic panel (11) must be arranged in sufficiently large sound walls in order to exclude the occurrence of an acoustic short circuit between the front part and the back part of the panel. Apart from being costly, only one side of the sound walls is actively used for sound generation as a result of the separation of both acoustic panels (11). Hence, the invention aims at providing a panel loudspeaker (10) that does not require any additional sound walls in order to exclude the occurrence of an acoustic short circuit while at the same time enabling full utilization of the surface of the acoustic panel (11) for sound generation.

Abstract: A panel loudspeaker with a low mass panel, a holder for retaining the panel and at least one driver with a vibrating connection to the panel for producing mechanical vibrations as a function of electrical drive signals, where the panel is bent at least in one dimension.

Abstract: The invention proposes a contact connection for sound reproduction devices according to the flexural wave principle. Since the drive systems 21 of such installations require high current intensities and such current intensities could only be properly transmitted by massive contact connections which however hinder the flexural wave propagation, the object of the invention is to propose a contact connection which eliminates the problems of the state of the art, and which is also very easy to implement. To that end it is proposed that at least one of the two cover layers 12 and/or the core layer 11 contain conductive areas 17 which are connected to the lines 32 of a sound signal source. It is particularly advantageous if the conductive areas 17 can be manufactured together with the components that are also used to manufacture the core layer 11.

Abstract: The invention relates to the embodiment of panel loudspeakers 10 working according to the bending wave principle. Such loudspeakers 10 generally consist of an acoustic panel 11 and drivers 12, whereby the drivers 12 are connected to the acoustic panel 11. For the formation of bending waves in the acoustic panel 11, it is essentially important that the drivers 12 do not unnecessarily rigidize the acoustic panel 11. This has led to the arrangement of the drivers 12 at a distance from the acoustic panel 11 in a separate frame. In view of the complexity of such an arrangement, the invention aims at providing a connection between the drivers 12 and the acoustic panel 11 that can be supported directly on the acoustic panel 11 and which does not impede the propagation of the bending waves. This is achieved by connecting the drivers to the acoustic panel only at very few points 24 or by providing elastic member 25 in the fixing area of the drivers. A combination of both embodiments is also described.

Abstract: A projection screen, having a projection surface formed of at least two segments, of which at least two segments are sound radiating segments capable of radiating sound waves from the projection surface and designed to reproduce different frequency ranges.

Abstract: The invention concerns the embodiment of drivers for panel loudspeakers. Panel loudspeakers working according to the principle of bending waves are already known in prior art. Said loudspeakers generally consist of an acoustic panel (11) and at least one driver (12). As a general rule, the driver (12) is arranged on an auxiliary frame at a distance from the acoustic panel (11). Said embodiment makes it possible to use conventional drivers (12) that can also be utilized in cone loudspeakers. A series of problem arise when the drivers (12) are to be integrated on or into the acoustic panel (11) itself. Said embodiment requires inter alia that the different components of the driver (12) be directly mounted on the acoustic panel (12). Hence, the invention aims at providing a driver for panel loudspeakers that can be connected with little complications to the acoustic panel (11) as a pre-fabricated component.

Abstract: A tweeter with a light, thin sandwich plate which can be excited into multiple reflected bending waves, and a driver which makes a vibrating contact and excites the sandwich plate, where the driver is designed for higher sound frequencies and the sandwich plate for propagating bending waves with low damping. The sandwich plate is freely carried with low damping by holding elements, where the latter are designed to be low damping at higher sound frequencies.

Abstract: A flat panel loudspeaker arrangement with several identical panel loudspeakers is disclosed. The panel loudspeakers are arranged seamlessly side-by-side and are rigidly connected with one another along their respective edges with a high shear strength. The panel loudspeakers can be supported by an existing stable wall.

Abstract: The invention presents a sound reproduction device which operates in accordance with the flexural wave principle. Such devices have in common that a panel 10 is provided in which flexural waves are produced by a drive arrangement 16. The drive arrangements 16 in the state of the art are connected to one of the surfaces of the panel 10 and are held by a support structure which functions as a countersupport. Such support structures either hinder the propagation of the flexural waves along the surface of the panel 10 and/or lead to an increase in the constructed depth of such a sound reproduction device. To avoid these disadvantages of the state of the art, the drive system 16 is located in a cutout 15 of the panel 10.

Abstract: The invention relates to acoustic walls for large public events. Traditionally, sound is reproduced by using a plurality of large and heavy loudspeaker boxes which requires a complicated and expensive support system. The present invention provides a segmented acoustic wall which has an essentially flat shape and is also extremely lightweight. Several of these segments can be integrated to form an acoustic wall by coupling the different segments with one another, whereby the entire surface area of the acoustic wall can be used to radiate sound without requiring additional sound sources in the audience space. The various segments can be optimized for certain frequency ranges by tuning the surface area and depth of the respective segments to the respective transmitted frequencies. Several acoustic walls can be placed side-by-side to flexibly conform to different requirements in the audience space.

Abstract: The invention proposes a suspension mount for sound reproduction devices according to the flexural wave principle. Characteristic for such devices is that a panel 10 is provided which must be flexibly attached to a holder 17. The panel 10 is composed of a core layer with a perforated structure, and two cover layers 12 which cover the core layer 11. Since the usual edge borders of conventional loudspeakers must be designed very hard due to the size and weight of the panel 10, the quality of the sound reproduction by such a device is reduced. For that reason the objective of the invention is a suspension mount which avoids the drawbacks of the state of the art. To that end it is proposed to build the suspension mount with the core layer 11 and/or at least one of the cover layers 12. If the core layer 11 itself provides the flexible attachment, it is also possible without any great effort to flexibly attach the panel 10 away from the edge areas.

Abstract: In order to avoid marking by the supporting surfaces in an endless belt for paper machines or the like with a number of helices consisting of opposing winding legs and headcurves joining these flanks together and into whose intermediary spaces the headcurves of the neighboring helix are forced to a degree that there develops between the two helices a range of overlapping into which a rod is inserted and in order to create the possibility for regulating the flow of air through the wire belt, at least the paper web-supporting winding legs of the helices are glued with a layer of fiber segments. Additionally, in such an endless belt permeability may be controlled by providing fiber segments on the winding legs and/or on the side areas adjacent the loop flanks.

Abstract: In order to avoid marking by the supporting surfaces in an endless belt for paper machines or the like with a number of helices consisting of opposing winding legs and headcurves joining these flanks together and into whose intermediary spaces the headcurves of the neighboring helix are forced to a degree that there develops between the two helices a range of overlapping into which a rod is inserted and in order to create the possibility for regulating the flow of air through the wire belt, at least the paper web-supporting winding legs of the helices are glued with a layer of fiber segments. Additionally, in such an endless belt permeability may be controlled by providing fiber segments on the winding legs and/or on the side areas adjacent the loop flanks.

Abstract: An endless sieve band or composite band for paper machines and the like, has a plurality of helixes composed of an elastic wire and each having two opposite winding legs and also two head curves connecting the winding legs with one another and having a predetermined wire diameter and wire width, wherein the helixes are arranged so that when the head curve of one of two neighboring helixes is inserted into an intermediate space of another of the two neighboring helixes an overlapping region is formed into which an insertion wire is introduced, and the winding legs of each of the helixes include a supporting winding leg which has flat supporting sufaces with a width exceeding the wire diameter or the wire width of the head curves.

Abstract: In a method and an arrangement for winding and forming helixes of elastic synthetic plastic and metal wire the wire is supplied from a wire supply device, windings are then wound from the wire so as to form straight winding legs connected by head curves, the windings are then separated to provide distances therebetween, the separated windings are widened in correspondence with the distances between them produced during the separation and the finished helixes are supplied to a helix supply device.

Abstract: Helixes are assembled into face structures by providing an initial helix which is stretched and retained on a work table, and a first helix which is attached to the initial helix, inserting into the first helix of a prestretched second helix by means of a joining tool and from a discharge conduit so that the second helix exits from the discharge conduit at an acute angle with respect to the first helix and moved along the latter connecting the second helix with the first helix by inserting an insert wire into the overlapping areas between the head arches of the first and second helixes, and displacing the thus finished face structure by a predetermined distance between insert wires in a timed sequence before a subsequent such inserting step for a further helix to be inserted into the second helix.