EP3197178A1 - Loudspeaker - Google Patents

Abstract

A loudspeaker comprises a surface array (10) of caseless single loudspeakers (11a, 11b, 11c) having a flat shape. The caseless single speakers are housed in a flat housing (1), wherein the depth of the housing, for example, is less than 5 cm. As caseless single loudspeakers preferably headphone capsules or miniature loudspeakers with a membrane diameter of less than 5 cm are used.

Description

The present invention relates to sound reproduction systems, and more particularly to loudspeakers with high sound reproduction bandwidth.

Interest in flat panel speaker technologies has grown significantly in the last 10 years. In essence, this is due to the increased space requirements of modern sound reproduction methods, such as e.g. 5.1 surround or wave field synthesis, and by the dwindling installation space for speakers in ever smaller or flatter multimedia devices, such as, e.g. Mobile phone and notebook, conditionally. The use of flat speakers instead of conventional speakers should meet these increased requirements.

Research on various flat panel speaker technologies, which are generally the same age as the Kellogg and Rice cone speakers, has shown that both the use of the flush-mount flat speaker directly on the wall and the use of a flat loudspeaker enclosure is associated with significant loss of sound. The state of the art is found in Beer, D .: Flat Loudspeakers - an overview, presented at the DAGA08, March 2008, Dresd s; H. Azima, J. Panzer, "Distributed-Mode Loudspeakers (DML) in Small Enclosures", presented at the 106th AES Convention, Munich, Germany, May 1999 ; Beer et al .: The air spring effect of flat panel speakers, presented at the 124th AES Convention, May 2008, Amsterdam / The Netherlands ; and Wagner, Roland: Electrostatic Loudspeaker - Design and Construction. Audio Amateurs Press, Peterborough, New Hampshire, 1993 ,

The caseless flat speaker is usually a dipole radiator, which has a low sound pressure level in the low frequency range due to the acoustic short circuit. When installing near the wall it comes in such a dipole by the reflection and superposition of the rearward sound component with the shares, the radiated on the membrane front sound and related diffraction effects to comb filter-like sound discoloration above the short circuit frequency. For this reason, a speaker cabinet is used in conventional speakers. However, to retain the benefit of the flat design, flat housings are typically used, which typically include a smaller volume of air. As with conventional loudspeakers, the basic resonance frequency of the sound transducer shifts upward due to an excessively small volume of air. As a result, the lower limit frequency also increases, resulting in decreased low-frequency reproduction.

The US 2005/0201583 A1 discloses a low frequency surface array based on a dipole principle. The system includes an open frame retention system wherein multiple subwoofers are housed in a dipole surface array configuration in the open frame system to provide controlled sound dispersion in both the horizontal and vertical planes. The subwoofers are operable to provide low frequency sound dispersion below about 300 Hz.

The DE 695 07 896 T2 discloses a directional sensitivity loudspeaker device comprising a first set of at least three loudspeakers arranged along a first straight line corresponding to a predetermined pattern, wherein the distances from loudspeaker to loudspeaker are made variable, and wherein loudspeakers can also be arranged in contact with each other ,

The U.S. Patent No. 2,602,860 discloses a speaker structure in which nine conical loudspeakers are arranged symmetrically in three rows of three each in a single frame. The frame includes segments tilted with each other to increase the angle of emission. So the distance between the edges of the speakers should be smaller than the radius of the speakers, all speakers are operated from a same source. Furthermore, no restriction with respect to the movement of air through a housing should be achieved, since this would impair the behavior at low frequencies.

The U.S. Patent No. 4,399,328 discloses a directional and frequency independent column of electroacoustic transducers which are driven at different amplitudes, resulting in certain ratios of driving the electroacoustic transducers.

The U.S. Patent No. 6,801,631 B1 discloses a loudspeaker system having a plurality of transducers positioned in a plane to achieve an optimal acoustic sound emission pattern. Four midrange converters (woofers) work together to reproduce the low and mid frequencies, with the woofers positioned so that no two woofers share a common vertical axis or common horizontal axis. Further, a fifth transducer, namely a high-frequency tweeter is provided, which is arranged in the middle of the woofer.

The object of the present invention is to provide an improved loudspeaker.

This object is achieved by a loudspeaker according to claim 1.

The present invention is based on the finding that a low-cost, flat and yet high-quality loudspeaker can be achieved by arranging a surface array of single caseless speakers, which all have a flat shape, in a flat housing, this loudspeaker a high reproduction bandwidth or a sufficient sound pressure in a desired narrow, z. B. deep, frequency range.

This speaker is advantageous in that the space requirement is very low due to the use of flat and typically small diameter single speakers. Also, the housing volume required per single loudspeaker is relatively small due to the fact that the caseless single loudspeakers are small and flat, so that the housing volume of the flat housing is so small that the entire loudspeaker has a compact design. In particular, an element which has a low outdoor resonance is preferred as a single loudspeaker. Then usually the equivalent volume of air is small. The stiffness of the membrane suspension of the single speaker is equated here with the stiffness of an equivalent volume of air. In this respect, single speakers with a resonant frequency less than 150 Hz and in particular even less than 120 Hz or even less than 100 Hz are preferred.

Another advantage of the present invention is that it allows the use of flat caseless single loudspeakers, providing the required housing volume with an almost arbitrary form factor, ie with a flat housing. The use of housing-less single speakers with a flat form factor also has the advantage that these single speakers are available at very low cost in large quantities. By arrangement This caseless single speaker in a surface array, a coupling of the speakers is used at low frequencies to produce even at low frequencies, such as at 100 Hz sufficient sound pressure. On the other hand, the use of small single speakers, so of individual speakers with a membrane diameter, which is relatively small, especially at high frequencies of great advantage compared to a use of speakers with larger membranes, because with small membranes over larger membranes only at higher frequencies partial vibrations occur.

Another advantage is that a variable control of the many caseless individual speakers, and thus of subareas of the surface array can be done. It should be possible to achieve as far as possible a location-independent full-range sound in the space in front of the loudspeaker, despite the fact that the loudspeaker has a single loudspeaker array of large dimensions.

Preferably, the loudspeaker comprises only identical individual loudspeakers, which may be, for example, headphone capsules or, in general, miniature sound transducers. This means that the production of the speaker is possible at a low price. In another preferred embodiment, the single loudspeakers are grouped into multiple arrays, with the array of individual subwoofers being provided for woofer reproduction, and an array of one or more identical single loudspeakers being provided for treble reproduction when using a 2-way system becomes. Alternatively, a 3-way system may also be implemented in which the second array includes multiple midrange drivers and the high-frequency range is preferably contested by a single or a few individual speakers. However, already provides a one-way system with caseless flat single speakers a good playback in a surprisingly large playback tape.

In another embodiment, it is preferred to provide only the low pass signal to the area array and provide the full bandwidth audio signal to the other array responsible for the medium or high tones. This means that a crossover in this case only has a low-pass function and no high-pass function.

In preferred embodiments of the present invention, speakers are obtained which, despite a flat loudspeaker enclosure of less than 5 cm, and more particularly less than 3 cm, depth with identical single loudspeakers, allow the frequency range from 100 Hz to 20 kHz to be reproduced with a sensitivity of at least 90dB / 1W / 1m , A preferred embodiment includes 25 miniature transducers which form an approximately 21x21cm area array comprising two sub-arrays for woofer reproduction and a line array for high-frequency reproduction present between these two subarrays.

Fig. 1a

eine Vorderansicht eines Lautsprechers gemäß einem ersten Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 1b

eine Rückansicht des Lautsprechers gemäß einem ersten Ausführungsbeispiel der Erfindung;

Fig. 1c

eine Verschaltung der gehäuselosen Einzellautsprecher gemäß einem Ausführungsbeispiel;

Fig. 1d

eine frequenzmäßige Aufteilung der Arrayelemente von Fig. 1a für eine 3-Wege-Ansteuerung;

Fig. 2a

eine Vorderansicht eines Lautsprechers gemäß einem zweiten Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 2b

eine Darstellung des Gehäuses des Lautsprechers von Fig. 2a;

Fig. 2c

eine Rückansicht des Lautsprechers von Fig. 2a ohne Gehäuserückwand;

Fig. 2d

eine Belegung der gehäuselosen Einzellautsprecher für eine 2-Wege-Ansteuerung;

Fig. 2e

eine alternative Implementierung des Lautsprechers von Fig. 2a mit angesetzten Fasen;

Fig. 3

eine Verschaltung der gehäuselosen Einzellautsprecher mit zusätzlicher Treiberelektronik für die in Fig. 2d gezeigte Lautsprecherbelegung;

Fig. 4a

eine schematische Darstellung des flachen Gehäuses des Lautsprechers von Fig. 2a, Fig. 2b und Fig. 2c;

Fig. 4b

eine alternative schematische Darstellung des Gehäuses des Lautsprechers von Fig. 2a, Fig. 2b und Fig. 2c;

Fig. 5a

eine Übertragungsfunktion einer Frequenzweiche für eine 2-Wege-Ansteuerung;

Fig. 5b

die Frequenzgänge des Hoch- und des Tieftonwegs für den in Fig. 2a gezeigten Lautsprecher;

Fig. 5c

einen Frequenzgang des 2-Wege- Lautsprechers gemäß Fig. 2a-2d ohne Entzerrung;

Fig. 5d

einen entzerrten Frequenzgang des Lautsprechers von Fig. 2a mit einer Ansteuerung gemäß Fig. 3;

Fig. 6a

eine Vorderansicht und eine Rückansicht eines bevorzugten gehäuselosen Einzellautsprechers in Form einer Kopfhörerkapsel;

Fig. 6b

technische Daten des gehäuselosen Einzellautsprechers von Fig. 6a;

Fig. 7a

eine schematische Darstellung eines Einsatzbereiches für Flachlautsprecher mit verkippt angeordneten Hoch- bzw. Mitteltönern; und

Fig. 7b

eine schematische Darstellung eines Lautsprechers mit einem zurückgesetzten Mittel- bzw. Hochtonarray mit einem Horn bzw. Wave-Guide zum Vergleichmäßigen der Richtcharakteristik des Mittelbzw. Hochtonarrays.

Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings. Show it:

Fig. 1a

a front view of a speaker according to a first embodiment of the present invention;

Fig. 1b

a rear view of the speaker according to a first embodiment of the invention;

Fig. 1c

an interconnection of caseless single loudspeakers according to an embodiment;

Fig. 1d

a frequency division of the array elements of Fig. 1a for a 3-way control;

Fig. 2a

a front view of a speaker according to a second embodiment of the present invention;

Fig. 2b

a representation of the housing of the speaker of Fig. 2a ;

Fig. 2c

a rear view of the speaker from Fig. 2a without rear panel;

Fig. 2d

an assignment of the caseless single loudspeakers for a 2-way control;

Fig. 2e

an alternative implementation of the loudspeaker of Fig. 2a with attached chamfers;

Fig. 3

an interconnection of caseless single speakers with additional driver electronics for in Fig. 2d shown speaker assignment;

Fig. 4a

a schematic representation of the flat housing of the speaker of Fig. 2a . Fig. 2b and Fig. 2c ;

Fig. 4b

an alternative schematic representation of the housing of the speaker of Fig. 2a . Fig. 2b and Fig. 2c ;

Fig. 5a

a transfer function of a crossover for a 2-way drive;

Fig. 5b

the frequency responses of the high and the low frequency range for the in Fig. 2a shown speakers;

Fig. 5c

a frequency response of the 2-way speaker according to Fig. 2a-2d without equalization;

Fig. 5d

an equalized frequency response of the loudspeaker of Fig. 2a with a drive according to Fig. 3 ;

Fig. 6a

a front view and a rear view of a preferred caseless single speaker in the form of a headphone capsule;

Fig. 6b

technical data of the housing-less single loudspeaker of Fig. 6a ;

Fig. 7a

a schematic representation of a field of application for flat speakers with tilted high or midrange drivers; and

Fig. 7b

a schematic representation of a loudspeaker with a recessed center or high pitch array with a horn or wave guide for the uniformity of the directivity of Mittelbzw. Tweeter array.

Fig. 1a shows a front view of a speaker according to an embodiment of the present invention. The speaker in Fig. 1a comprises a surface array 10 of caseless single loudspeakers 11a, 11b, 11c, ..., wherein each caseless single loudspeaker has a flat shape, as already with reference to the rear view in FIG Fig. 1b can be seen on the caseless single speaker 11d. In particular, the front view in Fig. 1a For each individual loudspeaker, the front area, ie a view of the loudspeaker 's membrane, while the rear view illustrates that the entire single loudspeaker is so flat that it can be seen in the loudspeaker Fig. 1b shown housing or is received in the corresponding housing bore and hardly protrudes beyond the bore. As it is still based on Fig. 4a is visible in the caseless single speaker, the example in Fig. 1b and Fig. 1a is inserted, and the in Fig. 6a is shown in detail, the individual speakers almost completely included in the total thickness of the material of the speaker front wall, such that the speaker protrudes only a small piece on the front wall housing and back protruding from the front wall of the housing also only a small piece, the board from the front wall of the housing at a Embodiment is only 4.5mm and the speaker protrudes only about 1.5mm on the rear side of the housing front wall and thus is an extremely flat single speaker.

Nevertheless, it is preferred because of the better behavior to use electrodynamic caseless single speakers, which are basically built like cone speakers. Cone speakers already have a system-related minimum depth. However, especially in the case of headphone capsules, this depth is very low, so that headphone capsules, as for example in Fig. 6a and Fig. 6b are shown, with a very small depth, namely, for example, only with a depth of 10.6 mm, are suitable and are also offered inexpensively.

Fig. 1c shows a control of the individual caseless single speakers in Fig. 1a in the case of a 1-way implementation. In particular, at least two groups of at least two loudspeakers are formed from the housing-less individual loudspeakers of the area array, wherein in the in Fig. 1c In the embodiment shown, five groups 12a-12e are formed, each group comprising five individual loudspeakers, so that the entire loudspeaker comprises a total of 25 single caseless loudspeakers.

In general, it is preferred to provide speakers whose number of individual speakers varies between 9 and 49, the exact number of individual speakers depending on how the individual ratios of the individual speakers are, and what sound pressure level, especially in the lower frequency range for which the speaker is provided, is required.

At the in Fig. 1a and Fig. 1b shown embodiment, the membrane diameter of a single speaker is 36 mm. In preferred embodiments caseless single speakers are preferred, the membrane diameter is smaller than 5 cm and preferably even less than 4cm, since in the surface array array according to the invention, the behavior in the high frequency range is better, the smaller the membrane diameter of a single speaker. Smaller membrane areas, achieved by using smaller single speakers, and the use of single caseless speakers allow for a denser arrangement of the individual speakers, thereby reducing the overall size of the array. This leads to a reduced directivity. In addition, partial vibrations, which can lead to pronounced spatial variations in the sound pressure level in the room, are shifted towards less critical higher frequencies. Although the partial vibrations also occur there, they are no longer disturbing due to the fact that they are not at low frequencies.

The associated drop in the sound pressure level at low frequencies is compensated for by a coupled arrangement of several individual speakers in the array, but it is essential that the individual speakers for woofer reproduction be arranged in an area array and not in a line array. An area array requires at least two adjacent rows, where one row must have at least two speakers and the other row must have at least one speaker. So is already a triangular arrangement of the speakers 11a, 11b, 11c in Fig. 1a a surface array, with surface arrays in the form of a rectangle, square or a circle or an ellipse are preferred. In particular, a square array is most preferred because the square shape Coming closest to the circular shape and the somewhat rectangular arrangement of the individual individual speakers, which leads to a total square for the area array, it makes it possible to arrange the individual speakers as close as possible to each other. In particular, the individual loudspeakers are arranged so close to each other that they touch each other, or that there is a direct distance between the individual loudspeakers which are adjacent to one another which is smaller than 5 mm and in particular smaller than 3 mm.

In the Fig. 1c shown serial / parallel circuit allows the entire speaker array still has a significant ohmic resistance, compared to the situation in which all the speakers are connected in parallel, so that the flowing current does not exceed the capacity of the voice coil voice coil , Compared to a complete series connection of all individual loudspeakers, however, it is achieved by the series-parallel connection that not all the loudspeakers connected in series influence each other electrically. The serial / parallel circuit according to Fig. 1c thus represents a good compromise between the complexity of the wiring of the individual speakers and the specifications for maximum current given by the individual speakers.

Fig. 1d shows an alternative implementation of the in Fig. 1a shown embodiment in which the individual speakers similar to in Fig. 1a are arranged, but are controlled as a 3-way system. Here, the area array of caseless single speakers is formed into a first array half 13a of woofer speakers and a second array half 13b of woofer speakers. These two array halves or subarrays are separated by another array of midtone speakers 13c and yet another array consisting of only a single tweeter speaker 13d. At the in Fig. 1d In the implementation shown, the two individual loudspeakers designated by "x" are short-circuited, ie deactivated. to the effect that these two individual speakers do not contribute to the sound output and swinging can be prevented as a passive membrane.

At the in Fig. 1d In the embodiment shown, it can be seen that the number of sub woofers is much greater than the number of midrange loudspeakers or treble loudspeakers. This split in favor of low-frequency reproduction is made to provide sufficient low-frequency sound pressure by coupling the individual woofers for the low-frequency range achieved by placing the woof-to-bass loudspeakers as close together as possible in an area array becomes.

According to the invention, the reproduction of the frequency range from 100 Hz (-6dB) up to 20kHz (-6dB) with a sensitivity of 101 dB / 1W / in spite of a flat speaker housing of only 2.4 cm internal depth and the associated high spring stiffness of the trapped air volume 1m possible. For this purpose, a 21 cm x 21 cm array of 25 miniature sound transducers is formed and installed in a housing of size (LxWxH). The control of the individual drivers is adapted to the target of the most linear possible amplitude frequency response and a uniform directivity in the main listening direction. For this purpose, the array is designed as a three-way system. The array approach is therefore chosen to achieve the most uniform distribution of the driving force on the membrane and to move by means of many small membrane surfaces, the occurrence of partial vibrations to higher frequencies. In contrast to a large membrane area, the significantly lower weight of the single membrane is also of great advantage for the reproduction of high frequencies.

Especially for the wave field synthesis application, the array approach offers the possibility of changing the speaker spacing between adjacent reproduction channels, by the grouping of converters to a playback channel is possible. A boundary condition in wave field synthesis is the "spatial sampling frequency", which requires that for the aliasing-free reproduction of a tone of 1 kHz every 17 cm a loudspeaker element is present, which is controlled by its own signal. At 10 kHz, the distance should be 1.7 cm, but at 100 Hz at 1.7 m. A distance of 1.7 m can be easily fulfilled. A distance of 1.7 cm, however, difficult or only approximate. The flat loudspeaker according to the invention makes it possible to supply larger groups of individual loudspeakers with a low-pass filtered signal having a greater width. There is an advantageous synergy here because individual loudspeakers in the deep area are required anyway in a surface array in order to provide sufficient sound pressure. In contrast, adjacent groups or individual adjacent speakers are supplied with different loudspeaker signals to produce a small channel spacing for the higher frequencies which is on the order of the membrane diameter. The loudspeaker signal can each be a high-pass signal or a signal with high-pass and low-pass components.

Preferably, therefore, a further array of individual speakers is present, wherein individual loudspeakers are surface arrays grouped so that spatially adjacent wave field synthesis channels with limited bandwidth below 1 kHz by adjacent groups of individual speakers are reproduced, the distance is greater than that between adjacent single loudspeakers or compared to the groups of smaller groups that reproduce spatially adjacent wave field synthesis channels with signal components over 1 kHz.

According to the invention, a loudspeaker is obtained which has a linear frequency response over as large a frequency range as possible, good impulse behavior, a uniform radiation behavior that is useful for the application, and which is capable of producing a maximum sound pressure level of 101 dB or more at a 1 meter distance, with the speaker exceptionally flat. The flat speaker is advantageous in that it can be inconspicuously integrated into the environment and still has good transmission properties. The housing construction should be such that a particularly small overall depth of 5 and preferably 3.6 cm or even more preferably 3.0 cm is not exceeded. For this purpose, acoustic drivers are used, which have a very small depth. Preference is given to the electrodynamic principle of the cone speaker as a sound transducer, since this technology is well controlled and efficient. The required low depth requires the use of miniature speakers and thus requires small membrane areas. Therefore, individual drivers are used in a group arrangement, wherein it is possible in such a surface array, as opposed to a single large bending wave transducer or single piston radiator with the same membrane area to change the respective active radiator surface by frequency-dependent control of the array elements as needed. This option is advantageous in terms of avoiding side lobe formation at high frequencies and avoiding partial vibrations, the membrane radius being chosen as far as possible so that partial vibrations only occur at uncritical frequencies. Compared to known Dickenschwingern a much higher diaphragm stroke and thus a higher volume in the lower frequency range is reached. Therefore area arrays are favorable for the flat loudspeaker according to the invention.

Fig. 6a shows a front view and a rear view of a preferably used miniature loudspeaker or "miniature chassis". The miniature chassis is preferably as a rearward open earphone capsule, as in Fig. 6a shown, executed. The metrologically determined parameters of such a caseless single loudspeaker are in the table in Fig. 6b shown. The outdoor resonance frequency of such a single loudspeaker is 120 Hz.

Both at the in Fig. 1a shown speaker as well as the reference to the FIGS. 2a-2e discussed speaker according to another embodiment of the present invention, a closed housing is used. In another preferred embodiment, an open housing can be used, in particular with a bass reflex system, so a bass reflex enclosure as a Helmholtz resonator, as is known in the art.

With respect to the material of the flat housing, a suitably rigid material is preferred in order to obtain a sufficiently stiffened housing, which manages with a material thickness of less than 7 mm and in particular even with a material thickness of 3 mm or even less. It is preferred to use as the material steel sheet or profiled plastic, although wood can be used. It is preferred to minimize susceptibility to longitudinal and lateral modes of equal frequency such that the edge dimensions of the entire loudspeaker are not an integer multiple of each other or that the loudspeaker has non-parallel walls. Nevertheless, to have a desired optical impression with parallel walls, an inner housing with non-parallel walls can be placed in an outer housing with parallel walls. An example of an inside dimension of the in Fig. 1a shown embodiment is 61.5 cm wide, 80 cm high and 2.4 cm deep. When using a 6 mm MDF board material outside dimensions with a width of 63.7 cm, a height of 81.2 cm and a depth of 3.6 cm.

Against the resonating of the housing, it is preferred to introduce webs inside the housing between the front and back, and it is also preferred, on the rear wall of outside to apply profiles. As it is for example in Fig. 2a . 2 B As can be seen, it is preferred that the area array be central in width and parallel to the edges, but eccentric in height. The individual loudspeakers are housed in particular in individual holes and partially embedded in the housing material. The individual loudspeakers can eg be glued in with hot glue or another sealing material and in particular acoustically sealed.

An advantage of the array arrangement is the possibility to control individual elements and thus individual subareas of the array differently. In order to be able to determine the active elements of the array in a frequency-dependent manner, a multipath drive is preferably used. For this purpose, the area array, as it is based on Fig. 1d has been divided into two sub-arrays 13a, 13b for low-frequency reproduction.

Alternatively to the in Fig. 1d In the exemplary embodiment shown, a 2-way arrangement would consist of all the speakers in the middle column being deactivated or not being present except for the single one in the middle, with the single center loudspeaker then acting as the only tweeter. To increase the maximum achievable sound pressure level, the in Fig. 1d used 3-way system used. In particular, in order for the sound phases radiated from the 3 paths to be correctly superimposed, the mid-tone branch is delayed by 0.5 ms and the high-tone branch by 0.52 ms from the low-frequency array.

In order to further improve the radiation behavior, it is preferred to use a 2-way high-tone path control in the form of a Bessel-weighted linear array as shown in FIG Fig. 2d is shown schematically. Thus, a bundling and sidelobe formation is better suppressed. This effect will be even better if, as it is in Fig. 2d shown is the tweeter single speakers in the middle and divide the area array of woofer speakers into two sub-arrays 13a, 13b. In contrast to Fig. 1d exists in Fig. 2 but only another tweeter array 13e, the individual tweeters are driven with the weights as in Fig. 2d are indicated schematically. It should be pointed out that the weighting factors 0.5, 1, -1 have been obtained only on the basis of a circuit-technically simple realization of the Bessel weights, but that, mathematically, at 0.11, 0.44, 0.76, -0, 44 and 0.11, and can be realized only with great effort.

In the Fig. 2d The control shown takes place in such a way that the three individual loudspeakers in the middle of the array 13e are driven with full amplitude, but the lower of these three individual loudspeakers is driven with inverted phase, while the uppermost single loudspeaker and the lowest individual loudspeaker of the array 13e are driven at half amplitude become. These level and phase relationships can be implemented with very simple means, contrary to the factors calculated by Bessel. By paralleling the three middle individual speakers with a series connection of the speakers at the top and bottom of the array 13e, these amplitude ratios can be produced. The phase is in the single loudspeaker, a weighting factor "-1" in Fig. 2d has achieved, simply by reversing the connection as it is in Fig. 3 at 15 is shown.

Similar to Fig. 1c The four columns of the woofer array are grouped into four groups of five individual loudspeakers, with the groups connected in parallel. This results in a nominal impedance of 10 ohms for the tweeter array and a nominal impedance of 56 ohms for the woofer array. It could also be all parallel woofer speakers, but then a higher current would flow through the voice coil.

However, this could overload and destroy the voice coil wire of the individual speakers.

As it is in Fig. 3 is shown, in the embodiment, a crossover 16 is preferred with a cut-off frequency 710 Hz. For a larger array area, the crossover should have a smaller cutoff frequency, and for a smaller array area, the crossover should have a larger cutoff frequency. Because of the crossover, there is a high tone path 17a and a low tone path 17b, or broadly speaking only a low tone path and a full bandwidth path instead of the high tone path which has no bass portions which are preferably both equalized by an equalizer EQ 18a and 18b respectively, with the equalized signals further preferably amplified by an amplifier 19a and 19b, respectively.

At the in Fig. 2a A loudspeaker according to the second embodiment of the present invention also uses a closed system. The package is based on a calculation using the so-called Thiele-Small parameters of the caseless single speakers, where the overall _{Qtc of} the package and array combination is said to be 0.707. This tuning is also referred to as Butterworth tuning and is extremely impressive in one, with ideal free-air frequency response, maximum smooth frequency response and minimally achievable resonance frequency.

Fig. 2a shows a perspective view of the speaker according to the second embodiment with a housing front wall 1a and a housing side wall 1b, wherein the speaker is disposed in a low-reflection space. The housing front wall comprises a height and a width, wherein the height is greater than the width, and wherein it is preferred to center the array with respect to the width and insert edge-parallel, and not center the array with respect to the height, but to accommodate decentralized, as in Fig. 2b is shown. Fig. 2c shows a back view of the open loudspeaker, with webs 19a, 19b in the vertical direction and webs 19c in the horizontal direction. These webs, which are preferably formed completely from the front of the housing to the rear of the housing, allow encapsulation of differently driven single speakers. Pressure changes inside the loudspeaker caused by vibrations of individual membranes would otherwise have an effect on all single loudspeakers working on the same volume. In order to avoid this, the individual loudspeakers of the middle array column each work on an individually delimited volume, which is achieved by the webs 19a, 19b, 19c. Since these individual loudspeakers are used for the high-toned branch, that is to say they should operate far above their resonance frequency, an elaborate dimensioning of the resulting volume is not necessary. The volume connected to each tweeter single speaker is 0.0361 1. The dimensions of the volumes are determined by the dimensions of the single loudspeaker.

The struts 19a, 19b achieve additional stiffening of the housing and cause the volume for the woofer array to be divided into two chambers, as is known Fig. 2c or even out Fig. 4a or Fig. 4b is apparent. Dividing the total volume into two chambers for the sub-arrays of woofer loudspeakers leads to an efficient stiffening of the housing and to the fact that bending vibrations of the housing front and / or the housing rear wall and modes in the housing are suppressed, in order to have corresponding negative influences on the behavior of the housing Reduce speaker. Other stiffening elements, as at 21 in Fig. 4b or 22 in Fig. 4a are shown are inserted to improve the rigidity of the wood material used, which is relatively low. By minimizing the distances between the stiffening points, the resonating of the housing walls is prevented because of the high pressure inside when operating the speaker. Preferably, the height and width of the housing are not even multiples to the Training of simultaneous longitudinal and transverse modes not to favor. The inside depth is at the in Fig. 2a or 2b shown embodiment again 2.4 cm. The outside dimensions of in Fig. 2a shown embodiment are in width 35.2 cm, in height 46.2 cm and in depth 3.6 cm. These external dimensions are also in the schematic drawing in Fig. 4a indicated together with other preferred dimensions of this embodiment.

The eccentric placement of the array on the front of the speaker is preferred. The sound pressure of sound waves propagating from a sound source through a loudspeaker front changes as they hit an edge, because the energy of the wave splits to a different volume. In the case of a housing edge, a sound wave bends around the housing. The volume into which the sound wave propagates and the surface of the wavefront become larger. The sound pressure on this surface decreases. Due to the change in pressure, a second sound source with opposite phase arises at this edge. The sound emitted by this secondary sound source is superimposed with the sound radiated from the primary sound source. Depending on the transit time difference, which is influenced by the distance between the two sound sources and between the loudspeaker and the listening position, the frequency response of the loudspeaker alternately leads to constructive and destructive interference. If the path difference equivalent to the transit time difference corresponds to integer multiples of a wavelength, then minima occur at the corresponding frequencies, with integer multiples of half the wavelength, overshoots occur. If the array were to be placed centrally on the baffle, observation points near the 0 ° axis would experience superimposition of the interference phenomena due to equal run times with respect to right and left or upper and lower baffle edges. The consequence of this is a location-dependent frequency response, which in some cases is characterized by severe break-ins and overshoots. To avoid this, the position of the Arrays on the front panel selected so that the distance from the central single speaker to the top, bottom and the side edges of the housing are as different as possible and not integer multiples of each other. This prevents the unfavorable coincidence of interference effects.

The division of the housing into two equal-sized chambers by stiffening webs requires that the array is centered horizontally. For example, the distance from the center of the array to the side edges is 17.6 cm. The distance from the center of the array to the upper edge of the housing is set to 14.1 cm. The distance to the lower edge of the housing is thus 23.1 cm. Thus, the 6 mm thick strips in the embodiment, with which the Hochtontreiber be separated, do not hinder the air compression at the rear open membranes, not all individual speakers of the array are arranged without a gap. Instead, between the individual speakers of the middle column of the array and the individual speakers of the left and right adjacent columns a distance of 6 mm is made, as is Fig. 4a is apparent.

It is preferred to dampen the housing with insulating wool to avoid housing modes. An insulating wool with a thickness of 3 cm and a mass of 280 g / m ² can be used. Housing modes should be removed by absorption in the insulation energy so that they can not fully or not form. This principle works only at high speed sound. Since at the edges of housings in standing waves are always maximum pressure and minimum minima, therefore, no insulation material is introduced at the edges of the housing over a width of about 7 cm, as shown schematically in FIG Fig. 2c you can see.

Hereinafter, referring to FIGS Figures 5a-5d various measurements on the in Fig. 2a to Fig. 2d explained Speaker according to a preferred embodiment explained.

The separation of the audio signals into a high-tone branch and a low-frequency branch through the crossover 16 is performed by means of fourth-order Linkwitz-Riley filters for the crossover. The transfer function of the crossover is in Fig. 5b shown. The level of the high-frequency branch is raised by 3 dB compared to the low-frequency signal. The loudspeaker is preceded by an 80 Hz high pass, which is in Fig. 3 not shown.

The signal applied with this filtering is supplied to the array. Fig. 5b shows the frequency responses of high and low frequencies on the 0 ° axis. The acoustic summation of both paths gives the in Fig. 5c shown unbalanced frequency response. In order to bring both the linearity of the frequency response and the lower frequency closer to the stated requirements, it is preferred to perform an equalization using the equalizers 18a, 18b. An equalized frequency response is in Fig. 5d shown, in which a much better linearity can be seen, and in which also a significantly improved behavior in the lower frequency range and a lowered lower limit frequency has been obtained. So that the sound components emitted by both paths overlap in the transfer area as optimally as possible, it is preferable to delay the treble path by 0.17 ms. The frequency response at the in Fig. 5d metrologically characterized embodiment is linearized in the range of 100 Hz to 20 kHz, so that a ripple of +/- 2 dB can be achieved. The cut-off frequency at -6 dB is 100 Hz. At 20 kHz, the sound pressure level has also fallen by 6 dB. The average electrical sensitivity of the speaker is 101 dB / 1W / 1m. This value is high compared to conventional hi-fi speakers and is due to the high sensitivity of the caseless single speakers. Fig. 2e shows an alternative implementation of the flat housing with chamfers attached, to come closer to a housing front similar to a truncated pyramid for attenuating interference effects due to diffraction phenomena at the edges of the housing. This allows a better linear frequency response can be achieved.

In order to improve the sound pressure emitted by the speaker at lower frequencies, ie in the range of 100 Hz and below, in embodiments of the invention, the flat housing can be designed as a bass reflex enclosure, which is not completely closed, but has one or more openings in the baffle , which can also be extended as channels into the housing inside. The housing of a bass reflex system is a Helmholtz resonator with a closed mounting hole for the transducer. Within the bass reflex channel is an air mass, which oscillates at resonance at maximum amplitude. The resonator is tuned to a resonant frequency below the resonant frequency of the transducer and then contributes significantly to the sound radiation of the loudspeaker at low frequencies. A properly tuned bass reflex design has an impedance curve with two adjacent maxima. The maximum sound pressure is radiated by the bass reflex tube at the minimum f _b between the two impedance maxima. The sound pressure emitted by the bass reflex channel decreases in the direction of higher and lower frequencies. The goal of tuning a bass reflex system is the constructive superimposition of sound components emitted by the sound transducer and bass reflex port. In a preferred embodiment, a bass reflex opening on the lower side wall of the housing, which is for example in Fig. 2b is shown provided, this channel opening is designed rectangular with a width of 5 cm. The length of a reflex tube for a chamber then results, for example, to 3.3 cm. An optimized case has a width of 41.5 cm, height of 66.2 cm and depth of 2.4 cm, these dimensions are based on the internal dimensions Respectively. The opening of the bass reflex channel can be increased in other embodiments, in particular be increased over the entire width of a chamber of 17.2 cm, for example. Accordingly, the length of the reflex tube can be increased since the length must also be increased with increasing opening area if the tuning frequency is to be maintained.

In another implementation, the reflex opening can also be arranged on the upper narrow side of the housing.

In particular, a closed loudspeaker with a flat arrangement of 25 miniature loudspeakers as a sound transducer is preferred, wherein the number of sound transducers depending on the application can also be between 9 and 49. A square shape of the arrangement of the sound transducers is preferred, wherein the area array is divided into separate sub-arrays of the critical woofer-providing single loudspeakers preferably to work in separate volumes. Preferably, a symmetrical 2-way arrangement is used, wherein the individual speakers of the other arrays between the two sub-arrays, which work as a tweeter, are weighted by coefficients of Bessel functions. The excitation signal of the system is equalized with a loudspeaker controller and actively separated and amplified by means of two power amplifiers. This achieves hi-fi-standard values for the maximum achievable sound pressure level as well as for the ripple of the frequency response and harmonic distortion. The speaker is characterized by a continuous, not overly bundling straightening behavior without sidelobes.

Speakers according to the present invention can be used both in classic stereo or multi-channel setups, preferably with a subwoofer for the lowest frequency range. The array concept leads to a high scalability of the system. So can with loudspeaker panels for Wave field synthesis of the spacing of adjacent playback channels are minimized by the small diameter of the individual speakers. Due to the possibility of discretely controlling individual caseless single loudspeakers and thus certain areas of an array, it is also possible to use time-modifiable actuators. The bundling effect of the loudspeaker in the vertical plane above 10 kHz can be further reduced by a modified array drive, if above 10 kHz only a single speaker is operated. According to the directivity of the individual loudspeaker, the vertical radiation angle can be increased above 10 kHz with such a 3-way system. The sound pressure increase in the frequency response of the miniature driver used in the embodiments is preferably eliminated, so that no more equalization is necessary.

In the case of non-real-time critical use of the loudspeaker, it is preferred to use a linear-phase filter set for equalization. This can positively influence the group delay of the loudspeaker and controller system.

To improve the speaker at lower frequencies, it is preferred not to increase the array area, but to increase the radiated sound pressure by increasing the diaphragm stroke. When the diaphragm stroke is doubled, the radiated sound pressure ideally doubles as well. For this, however, the mechanics of the transducer must be designed for larger stroke. The force generated by the drive of an electrodynamic transducer is determined by the product of the magnetic flux density B of the magnet, the length 1 of the coil wire, and the flowing current I in the coil.

Preferably, the loudspeaker according to the invention is implemented as an active loudspeaker with internal signal processing on a DSP since there is one (eg active) crossover and an equalization and a multi-channel amplification can be used and integrated into the speaker housing.

The speaker according to the invention is characterized by an exceptionally small housing depth, by a cost-effective manufacturability and by convincing values both on the metrological side and on a subjective level.

Fig. 7a FIG. 12 shows a loudspeaker in which a further array of individual loudspeakers is preferably provided in the center of the loudspeaker, in which one or more individual loudspeakers are tilted with respect to the individual loudspeakers of the area array, such that a surface normal to an active surface of a single loudspeaker of the further array of FIG a surface normal to an active area of a single speaker of the area array differs. The tilt can be, for example, 30 degrees with respect to the normal and is preferably between 10 ° and 70 °. Then, a listener may have an orientation of the speakers even if the flat speaker is mounted on the wall and can not be rotated. However, alignment is not required for the approximate omnidirectional pattern of the woofer array.

Fig. 7b shows a speaker in which there is another array of individual speakers, which is reset in the housing, or which has a waveguide device in front of the active surface. Preferably, a reset and waveguide structure is used to have a flat surface of the loudspeaker. In addition, the reset of the tweeter in the middle is not critical, because the necessary volume of air for the tweeter due to the high frequencies is small or total irrelevant. The waveguide structure serves to do the inherent Directivity in the intended area and it will have a horn-like shape.

1. 1. Lautsprecher, mit folgenden Merkmalen:
   • einem Flächen-Array (10) aus gehäuselosen Einzellautsprechern, die eine flache Form haben; und
   • einem flachen Gehäuse (1), in das die Einzellautsprecher (11a, 11b, 11c) untergebracht sind, wobei das flache Gehäuse ein Vorderwand, eine Rückwand, und eine Seitenwand aufweist, und
   • wobei das flache Gehäuse (1) eine Tiefe kleiner als 5 cm aufweist, oder wobei ein Durchmesser eines gehäuselosen Einzellautsprechers (11a, 11b, 11c) des Flächen-Arrays (10) kleiner als 5 cm ist.
2. 2. Lautsprecher nach Beispiel 1,
   bei dem ein weiteres Array (13b, 13c, 13e) aus Einzellautsprechern vorhanden ist, wobei ein kleinster Abstand eines Einzellautsprechers des weiteren Arrays zu einem Einzellautsprecher des Flächen-Arrays größer ist als ein kleinster Abstand zwischen zwei direkt benachbarten Einzellautsprechern des Flächen-Arrays (13a, 13b); und
   der ferner eine Frequenzweiche (16) zum Liefern eines Hochpass-Signals (17a) und eines Tiefpass-Signals (17b) aufweist, wobei das Hochpass-Signal zum Ansteuern eines weiteren Arrays (13e) und das Tiefpass-Signal (17b) zum Ansteuern des Flächen-Arrays (1; 13a, 13b) verwendet werden.
3. 3. Lautsprecher nach Beispiel 1, bei dem ein weiteres Array (13b, 13c, 13e) aus Einzellautsprechern vorhanden ist, wobei ein kleinster Abstand eines Einzellautsprechers des weiteren Arrays zu einem Einzellautsprecher des Flächen-Arrays größer ist als ein kleinster Abstand zwischen zwei direkt benachbarten Einzellautsprechern.
4. 4. Lautsprecher nach Beispiel 2 oder 3, bei dem das Flächen-Array ein erstes flächiges Teil-Array (13a) und ein zweites flächiges Teil-Array (13b) aufweist, zwischen denen das weitere Array (13c, 13d, 13e) angeordnet ist.
5. 5. Lautsprecher nach einem der Beispiele 3 bis 4, der ferner folgendes Merkmal aufweist:
   • eine Frequenzweiche (16) zum Liefern eines Hochpass-Signals (17a) und eines Tiefpass-Signals (17b), wobei das Hochpass-Signal zum Ansteuern eines weiteren Arrays (13e) und das Tiefpass-Signal (17b) zum Ansteuern des Flächen-Arrays (1; 13a, 13b) verwendet werden.
6. 6. Lautsprecher nach Beispiel 5, bei dem für das Hochpass-Signal und/oder das Tiefpass-Signal ein Entzerrer (18a, 18b) und/oder ein Verstärker (19a, 19b) vorgesehen sind, die ausgebildet sind, um ein Frequenzverhalten einer Schallausgabe des Lautsprechers in einem vordefinierten Frequenzbereich zu vergleichmäßigen.
7. 7. Lautsprecher nach einem der Beispiele 2 bis 6, bei dem das Gehäuse (1) im Inneren einen oder mehrere Stege (19a, 19b, 19c) zum Verbinden einer Vorderwand und einer Rückwand des flachen Gehäuses aufweist, wobei der mindestens eine Steg so angeordnet ist, dass er zwischen einem Einzellautsprecher des Flächen-Arrays (1) und einem benachbarten Einzellautsprecher des weiteren Arrays (13e) angeordnet ist.
8. 8. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem das Flächen-Array so in einer Vorderwand des Gehäuses exzentrisch angeordnet ist, dass ein Mittelpunkt des Arrays von einem Mittelpunkt der Vorderwand um wenigstens 10 % der kürzeren Seite der Vorderwand unterschiedlich ist.
9. 9. Lautsprecher nach einem der Beispiele 2 bis 8, bei dem eine Anzahl von Einzellautsprechern in dem Flächen-Array (1; 13a, 13b) wenigstens doppelt so groß ist wie in dem weiteren Array (13c, 13d, 13e).
10. 10. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem das Flächen-Array wenigstens zwei Gruppen (12a, 12b, 12c, 12d, 12e) von Einzellautsprechern aufweist, wobei jede Gruppe wenigstens zwei Einzellautsprecher aufweist, wobei die Einzellautsprecher in einer Gruppe seriell geschaltet sind, und wobei die Gruppen parallel geschaltet sind.
11. 11. Lautsprecher nach einem der Beispiele 2 bis 10, bei dem das weitere Array (13e) ein Linien-Array von Lautsprechern ist, wobei eine Ansteuerungsschaltung vorhanden ist, die ausgebildet ist, um äußere Einzellautsprecher des weiteren Arrays mit einem amplitudenmäßig schwächeren Treibersignal als ein mittlerer Lautsprecher des weiteren Arrays zu versorgen.
12. 12. Lautsprecher nach einem der vorhergehenden Beispiele, in dem alle Einzellautsprecher des Flächen-Arrays oder alle Einzellautsprecher des Lautsprechers insgesamt identische aktive Flächen haben.
13. 13. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem alle Einzellautsprecher des Flächen-Arrays oder alle Einzellautsprecher des gesamten Lautsprechers elektrodynamische Lautsprecher sind.
14. 14. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem alle Einzellautsprecher des Flächen-Arrays oder alle Einzellautsprecher des gesamten Lautsprechers Konus-Lautsprecher oder Kolbenstrahler sind.
15. 15. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem alle Einzellautsprecher des Flächen-Arrays oder alle Einzellautsprecher des gesamten Lautsprechers Kopfhörerkapseln sind.
16. 16. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem die Lautsprecher so in dem Gehäuse angeordnet sind, dass zwischen einer Rückseite einer Membran jedes Einzellautsprechers des Flächen-Arrays und einer nächstliegenden Gehäusewand wenigstens ein Abstand von 0,8 cm und höchstens ein Abstand von 4 cm vorhanden ist.
17. 17. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem die Einzellautsprecher des Flächen-Arrays so nahe aneinander angeordnet sind, dass Ränder von benachbarten Einzellautsprechern weniger als 3 mm voneinander beabstandet sind oder sich berühren.
18. 18. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem das Flächen-Array ein erstes Teil-Array (13a) und ein zweites Teil-Array (13b) aufweist, wobei jedes Teil-Array zwei benachbarte Reihen von Einzellautsprechern aufweist, und wobei ein weiteres Array eine einzige Reihe von Einzellautsprechern aufweist, wobei eine Anzahl der Einzellautsprecher pro Reihe für alle Reihen und Arrays gleich ist.
19. 19. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem das Gehäuse so groß ist, dass es ein Volumen aufweist, das gleich einem pro Einzellautsprecher des Flächen-Array geforderten Minimalvolumens multipliziert mit der Gesamtanzahl der Einzellautsprecher des Flächen-Arrays ist.
20. 20. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem eine Tiefe des flachen Gehäuses kleiner als 1/10 der kürzeren Seite einer Vorderwand oder Rückwand des Gehäuses ist.
21. 21. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem alle Einzellautsprecher des Flächen-Arrays so verschaltet sind, dass sie mit Ansteuersignalen angesteuert werden, die zueinander abgesehen von unterschiedlichen Leitungslängen keine Phasenverschiebung haben, wobei zwischen den Einzellautsprechern und einem Treiberausgang kein Phasenschieber vorhanden ist, und
    wobei die Einzellautsprecher des Flächen-Arrays ausgebildet sind, um die gesamte Schallbandbreite in einem 1-Weg-System zu liefern, oder um einen Tieftonbereich in einem Mehrwege-System zu liefern.
22. 22. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem das Flächen-Array in ein erstes Teil-Array (13a) und ein zweites Teil-Array (13b) aufgeteilt ist, wobei das Gehäuse eine durchgehende Trennung (19a, 19b) aufweist, um für das erste Teil-Array (13a) ein erstes Gehäusevolumen bereitzustellen und für das zweite Teil-Array (13b) ein zweites Gehäusevolumen bereitzustellen, wobei das erste Gehäusevolumen und das zweite Gehäusevolumen durch die Trennung (19a, 19b) voneinander getrennt sind.
23. 23. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem ein weiteres Array von Einzellautsprechern vorhanden ist, das in dem Gehäuse zurückgesetzt ist, oder das vor der aktiven Fläche eine Wellenführungseinrichtung aufweist.
24. 24. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem ein weiteres Array von Einzellautsprechern vorhanden ist, bei dem einer oder mehrere Einzellautsprecher bezüglich der Einzellautsprecher des Flächenarrays verkippt angeordnet sind, so dass sich eine Flächennormale auf eine aktive Fläche eines Einzellautsprechers des weiteren Arrays von einer Flächennormale auf eine aktive Fläche eines Einzellautsprechers des Flächenarrays unterscheidet.
25. 25. Lautsprecher nach einem der vorhergehenden Beispiele, bei dem ein weiteres Array von Einzellautsprechern vorhanden ist, wobei Einzellautsprecher es Flächenarrays so gruppiert sind, dass räumlich benachbarte Wellenfeldsynthesekanäle mit begrenzter Bandbreite unter 1 KHz durch nebeneinander liegende Gruppen von Einzellautsprechern wiedergebbar sind, deren Abstand größer ist als der zwischen benachbarten Einzellautsprechern oder im Vergleich zu den Gruppen kleineren Grüppchen, die räumlich benachbarte Wellenfeldsynthesekanäle mit Signalanteilen über 1 kHz wiedergeben.

Hereinafter, examples of the present invention will be set forth.

1. 1. Speaker, with the following features:
   • a surface array (10) of caseless single loudspeakers having a flat shape; and
   • a flat housing (1) housing the individual speakers (11a, 11b, 11c), the flat housing having a front wall, a rear wall, and a side wall, and
   • wherein the flat housing (1) has a depth less than 5 cm, or wherein a diameter of a caseless single speaker (11a, 11b, 11c) of the area array (10) is smaller than 5 cm.
2. 2. loudspeaker according to example 1,
   in which a further array (13b, 13c, 13e) of single loudspeakers is present, wherein a smallest distance of a single loudspeaker of the further array to a single loudspeaker of the area array is greater than a smallest distance between two directly adjacent single loudspeakers of the area array (13a , 13b); and
   further comprising a diplexer (16) for providing a high-pass signal (17a) and a low-pass signal (17b), wherein the high-pass signal for driving another array (13e) and the low-pass signal (17b) for driving the Area arrays (1; 13a, 13b) are used.
3. 3. loudspeaker according to Example 1, in which a further array (13b, 13c, 13e) consists of individual loudspeakers, wherein a smallest distance of a single speaker of the further array to a single speaker of the area array is greater than a smallest distance between two directly adjacent individual speakers.
4. 4. Loudspeaker according to example 2 or 3, in which the surface array has a first planar sub-array (13a) and a second planar sub-array (13b), between which the further array (13c, 13d, 13e) is arranged ,
5. 5. A loudspeaker according to any one of Examples 3 to 4, further comprising:
   • a crossover network (16) for providing a high-pass signal (17a) and a low-pass signal (17b), the high-pass signal for driving another array (13e) and the low-pass signal (17b) for driving the area array (1; 13a, 13b).
6. 6. Loudspeaker according to Example 5, in which an equalizer (18a, 18b) and / or an amplifier (19a, 19b) are provided for the high-pass signal and / or the low-pass signal, which are adapted to a frequency response of a sound output to equalize the speaker in a predefined frequency range.
7. 7. A loudspeaker according to any one of Examples 2 to 6, wherein the housing (1) internally has one or more webs (19a, 19b, 19c) for connecting a front wall and a rear wall of the flat housing, wherein the at least one web is so arranged in that it is arranged between a single loudspeaker of the area array (1) and an adjacent single loudspeaker of the further array (13e).
8. 8. Loudspeaker according to one of the preceding examples, wherein the surface array is arranged eccentrically in a front wall of the housing, that a center of the Arrays from a center of the front wall is different by at least 10% of the shorter side of the front wall.
9. A loudspeaker according to any one of Examples 2 to 8, wherein a number of individual loudspeakers in the area array (1; 13a, 13b) are at least twice as large as in the further array (13c, 13d, 13e).
10. 10. A loudspeaker according to one of the preceding examples, in which the area array comprises at least two groups (12a, 12b, 12c, 12d, 12e) of individual loudspeakers, each group comprising at least two individual loudspeakers, the individual loudspeakers being connected in series in a group , and wherein the groups are connected in parallel.
11. 11. The loudspeaker according to one of examples 2 to 10, wherein the further array (13e) is a line array of loudspeakers, wherein a drive circuit is provided, which is adapted to external single speakers of the further array with an amplitude weaker driver signal than a middle speaker of the other arrays supply.
12. 12. Loudspeaker according to one of the preceding examples, in which all the individual loudspeakers of the area array or all the individual loudspeakers of the loudspeaker have identical active areas as a whole.
13. 13. Loudspeaker according to one of the preceding examples, in which all the individual loudspeakers of the area array or all the individual loudspeakers of the entire loudspeaker are electrodynamic loudspeakers.
14. 14. Loudspeaker according to one of the preceding examples, in which all the individual loudspeakers of the area array or all the individual loudspeakers of the entire loudspeaker are cone loudspeakers or piston emitters.
15. 15. A loudspeaker according to one of the preceding examples, in which all the individual loudspeakers of the area array or all the individual loudspeakers of the entire loudspeaker are headphone capsules.
16. 16. Loudspeaker according to one of the preceding examples, in which the loudspeakers are arranged in the housing such that between a rear side of a membrane of each individual loudspeaker of the area array and a nearest housing wall at least a distance of 0.8 cm and at most a distance of 4 cm is present.
17. 17. A loudspeaker according to one of the preceding examples, in which the individual loudspeakers of the area array are arranged so close to one another that edges of adjacent individual loudspeakers are less than 3 mm apart or touch each other.
18. 18. A loudspeaker according to one of the preceding examples, wherein the area array comprises a first sub-array (13a) and a second sub-array (13b), each sub-array comprising two adjacent rows of individual loudspeakers, and another Array has a single row of single speakers, wherein a number of individual speakers per row for all rows and arrays is the same.
19. 19. A loudspeaker according to one of the preceding examples, in which the housing is so large that it has a volume which is equal to a minimum volume required per single loudspeaker of the area array multiplied by the total number of individual loudspeakers of the area array.
20. 20. A loudspeaker according to any one of the preceding examples, wherein a depth of the flat housing is less than 1/10 of the shorter side of a front wall or rear wall of the housing.
21. 21. Loudspeaker according to one of the preceding examples, in which all the individual loudspeakers of the area array are connected in such a way that they are driven by drive signals which apart from different line lengths have no phase shift, wherein there is no phase shifter between the individual loudspeakers and a driver output, and
    wherein the single speakers of the area array are configured to provide the total sonic bandwidth in a one-way system or to provide a low frequency range in a multipath system.
22. 22. Loudspeaker according to one of the preceding examples, wherein the area array in a first sub-array (13 a) and a second sub-array (13 b) is divided, wherein the housing has a continuous separation (19 a, 19 b) to for the first sub-array (13a) to provide a first housing volume and to provide a second housing volume for the second sub-array (13b), the first housing volume and the second housing volume being separated by the partition (19a, 19b).
23. 23. Loudspeaker according to one of the preceding examples, in which there is a further array of individual loudspeakers, which is reset in the housing, or which has a waveguide device in front of the active surface.
24. 24. Loudspeaker according to one of the preceding examples, in which a further array of individual loudspeakers is provided in which one or more individual loudspeakers are tilted with respect to the individual loudspeakers of the area array, so that a surface normal to an active area of a single loudspeaker of the further array of a Area normal to an active area of a single speaker of the area array differs.
25. 25. Loudspeaker according to one of the preceding examples, in which a further array of individual loudspeakers is present, wherein individual loudspeakers are surface arrays grouped so that spatially adjacent wavefield synthesis channels with limited bandwidth below 1 kHz can be reproduced by adjacent groups of individual loudspeakers whose distance is greater than that between adjacent single loudspeakers or smaller groups compared to the groups representing spatially adjacent wave field synthesis channels with signal levels above 1 kHz.

Claims (15)

Speaker, with the following features: a surface array (10) of caseless single loudspeakers having a flat shape, the surface array having a first planar subarray (13a) and a second planar subarray (13b); another array (13b, 13c, 13e) of single loudspeakers having a flat shape, the further array (13b, 13c, 13e) being along a width of the front wall between the first planar sub-array (13a) and the second planar part Array (13b); a diplexer (16) for providing a high-pass signal (17a) and a low-pass signal (17b), the high-pass signal for driving the further array (13e) and the low-pass signal (17b) for driving the area array (1; 13a, 13b) are used; and a flat housing (1), the flat housing having a front wall, a rear wall, and a side wall, wherein the individual speakers (11a, 11b, 11c) are received in the front wall, and wherein the flat housing (1) has a depth less than 5 cm, or wherein a diameter of a caseless single speaker (11a, 11b, 11c) of the area array (10) is smaller than 5 cm, and wherein the surface array and the further array in a front wall of the housing to the edges of the front wall is arranged parallel, but eccentric .. Loudspeaker according to claim 1,
in which a smallest distance of a single loudspeaker of the further array to a single loudspeaker of the area array is greater than a smallest distance between two directly adjacent individual loudspeakers of the area array (13a, 13b). A loudspeaker according to claim 1 or 2, wherein an equalizer (18a, 18b) and / or an amplifier (19a, 19b) are provided for the high-pass signal and / or the low-pass signal, which are adapted to a frequency response of a sound output to equalize the speaker in a predefined frequency range. A loudspeaker according to any one of claims 1 to 3, wherein the housing (1) internally has one or more webs (19a, 19b, 19c) for connecting a front wall and a rear wall of the flat housing, the at least one web being arranged in that it is arranged between a single loudspeaker of the area array (1) and an adjacent individual loudspeaker of the further array (13e). The loudspeaker of claim 1, wherein the array of faces is eccentrically disposed in a front wall of the housing such that a center of the array is different from a center of the front wall by at least 10% of the shorter side of the front wall. A loudspeaker according to any one of claims 1 to 5, wherein a number of individual loudspeakers in the area array (1; 13a, 13b) are at least twice as large as in the further array (13c, 13d, 13e). A loudspeaker according to any one of the preceding claims, wherein the area array comprises at least two groups (12a, 12b, 12c, 12d, 12e) of individual loudspeakers, each group having at least two individual loudspeakers, the single loudspeakers being connected in series in a group, and the groups being connected in parallel. A loudspeaker according to any one of claims 1 to 7, wherein the further array (13e) is a line array of loudspeakers, there being a driving circuit adapted to produce single external loudspeakers of the further array having an amplitude weaker driver signal than a middle loudspeaker to supply the array further. A loudspeaker according to one of the preceding claims, in which all the individual loudspeakers of the area array or all the individual loudspeakers of the loudspeaker have identical active areas as a whole. Loudspeaker according to one of the preceding claims, in which the loudspeakers are arranged in the housing such that there is at least a distance of 0.8 cm and a distance of at most 4 cm between a back side of a membrane of each individual loudspeaker of the area array and a nearest housing wall is. A loudspeaker according to any one of the preceding claims, wherein a depth of the flat casing is less than 1/10 of the shorter side of a front wall or rear wall of the casing. A loudspeaker according to any one of the preceding claims, wherein the housing has a continuous partition (19a, 19b) for providing a first housing volume for the first sub-array (13a) and providing a second housing volume for the second sub-array (13b), wherein the first housing volume and the second housing volume separated by the separation (19a, 19b). A loudspeaker according to any one of the preceding claims, wherein there is the further array of individual loudspeakers which is recessed in the housing or which has waveguide means in front of the active surface. Loudspeaker according to one of the preceding claims, in which in the further array of individual loudspeakers one or more individual loudspeakers are tilted with respect to the individual loudspeakers of the surface array, so that a surface normal to an active surface of a single loudspeaker of the further array from a surface normal to an active surface of a Single speaker of the area array differs. A loudspeaker according to claim 1, wherein said area array and said further array are centrally located with respect to width.

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