This application claims priority to German Patent Application 10 2013 110 535.1, filed on Sep. 24, 2013, which is incorporated herein by reference.
The disclosure relates to a bass reflex loudspeaker system with a phase correction element.
Bass reflex loudspeaker systems are frequently used in sound engineering. In bass reflex loudspeaker systems, the loudspeaker housing is not closed, but rather provided with a channel leading to the outside. The term ventilated or vented systems is also used. The sound component radiated backwards from the loudspeaker is used in order to increase the efficiency of the loudspeaker system in the region of the resonant frequency of the loudspeaker system. It is possible to achieve significantly increased sound pressure levels and an extension of the power bandwidth.
An object of various embodiments can be considered to be that of providing a loudspeaker system having good sound properties, small physical size and/or a high sound pressure level.
The loudspeaker system may comprise a loudspeaker housing that has at least a first and a second housing chamber. A bass loudspeaker is mounted on a partition (partition board) between the first housing chamber and the second housing chamber, wherein the sound at the back of the bass loudspeaker is radiated into the first housing chamber and the sound at the front of the bass loudspeaker is radiated into the second housing chamber.
Further, a loudspeaker system having a loudspeaker, a first housing chamber into which the bass loudspeaker radiates at the back and that forms a first resonator, a second housing chamber into which the bass loudspeaker radiates at the front and that forms a second resonator, a bass reflex resonator that interacts with the first resonator, and a phase correction element, which is accommodated in the second housing chamber, for decreasing the mode acuity of the second resonator is disclosed. At least one portion of the bass reflex resonator may, e.g., be arranged in the second housing chamber adjacent to the phase correction element.
Embodiments of the disclosure are explained below using exemplary embodiments with reference to the drawings, in which:
In the appended drawings, the same or similar parts are denoted by the same reference symbols. The dimensions shown in the Figures may be but are not necessarily to scale. The disclosure content of the drawings is therefore intended to entail both a specific, to-scale understanding of these Figures and a more general, not-to-scale understanding of the Figures in the sense of schematic illustrations. In addition, housing walls (e.g. bottom wall and top wall, side walls) that are shown parallel to one another in the Figures may be oriented parallel to one another, but in general it is also possible to have such walls in orientations inclined toward one another.
Features that are explained with reference to different embodiments can be combined with one another if they are not alternative features. By way of example, that is to say that elements explained with reference to one of the embodiments, for example the phase correction element and the various housing chambers and resonators, and also the properties thereof may also apply to the corresponding elements and the properties thereof in another embodiment.
It is to be understood that the features of the various exemplary embodiments described herein may be combined with each other, unless specifically noted otherwise.
The loudspeaker system described herein may have at least one bass reflex opening in the partition and a phase correction element that is arranged at the front of the bass loudspeaker in the second housing chamber. In this case, the bass reflex opening may open into the second housing chamber and may be arranged in a region adjacent to the phase correction element.
This adjacent physical arrangement of the phase correction element and the bass reflex opening may allow a space-saving design. A bass reflex channel (or duct) adjoining the bass reflex opening can have at least sections running in the second housing chamber and can be displaced therein into an otherwise “dead” volume, for example, in a region adjacent to the phase correction element, for example bounded by the back of the phase correction element. A loss of volume in the first housing chamber as the result of a bass reflex channel that, according to conventional design, projects into the first housing chamber can therefore be avoided or at least reduced.
This additionally usable volume in the first housing chamber may make the resonator formed by the first housing chamber more efficient, which results in a sound pressure level increase at its resonant frequency. At the same time or alternatively, a reduction in the physical size of the first housing chamber and hence of the entire loudspeaker housing in comparison with the conventional design with a bass reflex channel fully present in the first housing chamber can be achieved for a prescribed maximum sound pressure level.
The phase correction element, for example what is known as a phase plug, may have a flat, curved or else wing-shaped form. The form of the phase correction element produces a volume geometry in the second housing chamber that suppresses any undesirable higher resonance mode as far as possible, but in so doing impairs the desired fundamental resonance of the second housing chamber as little as possible. Above the fundamental resonance, the phase correction element thus prompts mode extension or a decrease in mode quality. The phase correction element attenuates or eliminates discrete or acute modes of the resonator, which impair the sound, at the front of the bass loudspeaker.
The phase correction element can extend radially outward from a central region—with reference to the direction of radiation—of the loudspeaker on both sides. By way of example, it can extend in the radial direction beyond the loudspeaker edge and possibly at least in sections as far as the edge of the loudspeaker housing.
The bass reflex opening provided in the partition may be formed in the region of a corner of the first housing chamber or of the loudspeaker housing. This makes it possible to obtain a space-saving design with a comparatively small physical size.
In addition, provision may be made for a wall section of the phase correction element to form a wall region of a bass reflex channel containing the bass reflex opening. This design allows a saving on material, since separate ducts or the like, as are conventionally used for a bass reflex channel, can be dispensed with at least in the region of the phase correction element.
In addition, a wall region of a bass reflex channel containing the bass reflex opening may be formed by at least one wall section of the second housing chamber, particularly by two mutually perpendicular wall sections of the second housing chamber. This measure likewise allows the achievement of a saving on material in the sense described above (use of the wall sections as a wall region of a bass reflex channel).
A bass reflex channel comprising the bass reflex opening can extend over less than 50% of its length, particularly over less than 30% of its length—and possibly not at all—into the first housing chamber. The use of a partial volume of the second housing chamber for the bass reflex channel allows the latter to be accommodated predominantly or possibly completely in the second housing chamber. This measure increases the effective volume of the first housing chamber, which acts as a resonator volume. The housing size can therefore be decreased for a desired maximum sound pressure level or the maximum achievable sound pressure level can be increased for a prescribed housing size.
A bass reflex channel containing the bass reflex opening may have a sound exit opening that is situated between at least one housing wall of the second housing chamber and a contour line of the phase correction element. Hence, the (otherwise “dead”) volume on the outside or back of the phase correction element can be used as a resonator volume for the bass reflex channel.
The sound exit opening of the bass reflex channel may be situated in a corner region of the second housing chamber. In this case, the volume in the corner region of the second housing chamber can be used as a resonator volume for the bass reflex channel.
A further possible variant embodiment involves the partition running at an inclination with respect to a back housing wall. This measure allows the physical height of the loudspeaker housing to be reduced further on account of the oblique installation position of the bass loudspeaker.
With an inclined partition, provision may be made for a bass reflex channel containing the bass reflex opening to extend at least from the rear end of the partition to the front end of the partition. That is to say that that section in the second housing chamber that is defined by the oblique position of the partition can be used to increase the volume of the bass reflex channel.
The loudspeaker system described herein may further comprise a further bass loudspeaker that is mounted on a further partition between the first housing chamber and the second housing chamber or a third housing chamber of the loudspeaker housing, wherein the back of the further bass loudspeaker has the first housing chamber present and the front of the further bass loudspeaker has the second or third housing chamber present. At least one further bass reflex opening may be present in the further partition. In addition, a further phase correction element may be present that is arranged at the front of the further bass loudspeaker in the second or third housing chamber. The further bass reflex opening can open into the second or third housing chamber and be arranged in a region adjacent to the further phase correction element.
Both the partition and the further partition can each run at an inclination with respect to a back housing wall. The effect that can be achieved by this is that there is a shorter distance between the two bass loudspeakers or the focus of radiation thereof. This reduces the height of the loudspeaker housing and promotes the physical radiation response toward high frequencies of the bass loudspeakers.
The loudspeaker system may further comprise a horn loudspeaker. The horn loudspeaker may be arranged between the bass loudspeaker and the further bass loudspeaker.
A sound exit opening of the bass reflex resonator may be arranged between a contour line of the phase correction element and a wall of the second housing chamber, particularly in a corner region of the second housing chamber. In addition, more than 50%, for example more than 80% and particularly 100%, of the air volume of the bass reflex resonator may be situated in the second housing chamber. These measures make it possible to attain a space-saving design and/or a high maximum sound pressure level for a given housing size, as already described.
By way of example, the loudspeaker housing 10 may have a width W in the y direction, a height H in the z direction and a depth T in the x direction. W, H and T may each be larger than 20 cm, 40 cm, 60 cm, 80 cm, 100 cm, with W, H and T being able to assume different values. As
The bass loudspeaker 50 radiates its front sound into the second housing chamber 30 and its backward sound into the first housing chamber 20. The first housing chamber 20 may contain—not shown—further chambers and/or further loudspeakers, see also
The first housing chamber 20 is connected to the second housing chamber 30 via at least one opening 41. The opening 41 is subsequently referred to as a bass reflex opening. In the embodiment of the loudspeaker system 100 that is shown here, the partition 40 contains a plurality of, for example, two bass reflex openings 41.
The one or more bass reflex opening(s) 41 may be situated in corner regions of the loudspeaker housing 10, for example. The bass reflex openings 41 may be in the form of corner cutouts in the partition 40. In this case, the bass reflex openings 41 are bounded by wall sections of the loudspeaker housing 10 that adjoin the corners and by an edge of the respective cutout in the partition 40.
The bass reflex openings 41 may have an approximately triangular shape, as can be seen in
Situated in the main direction of radiation x in front of the bass loudspeaker 50 is a phase correction element (phase plug) 60. The phase correction element 60 may have a flat-curved, wing-shaped or spade-shaped form. By way of example, as can be seen in
One or more side wall region(s) 60a, 60c and/or a bottom wall region 60b of the phase correction element 60 may be in contact with housing walls of the second housing chamber 30 or otherwise connected to the latter and may form an airtight closure with said housing walls, for example. The outer wall sections 60d, 60e of the phase correction element 60, which lie between the side wall regions 60a, 60b, 60c of the phase correction element 60 that close the housing walls, can form a wall region of a bass reflex channel (duct) 70 containing the bass reflex openings 41 in the X direction.
This means that the bass reflex channel 70 can be formed in the region of the second housing chamber 30 by wall areas of the second housing chamber 30 and/or by outer wall sections 60d, 60e of the phase correction element 60. It is possible for the bass reflex channel 70 in the second housing chamber 30 to be formed exclusively by housing wall areas and outer wall sections 60d, 60e of the phase correction element. In this case, it is not necessary for additional elements such as ducts or the like to be connected to the bass reflex openings 41 in the x direction in order to form a bass reflex channel. That is to say that the use of already present wall areas of the second housing chamber 30 and/or outer wall sections 60d, 60e of the phase correction element that are present can achieve a saving on material for the requisite production of the bass reflex channel 70.
However, it is also possible for the bass reflex channel 70 in the region of the second housing chamber 30 to be produced—not shown—by a length of duct that adjoins the bass reflex opening 41 and runs in the x direction. Such a length of duct (not shown) can extend in the x direction between the outer wall section 60d or 60e of the phase correction element 60 and the wall regions of the second housing chamber 30 that are close to the corners. The length of duct may have essentially the same cross-sectional opening as the bass reflex opening 41, i.e. may exhibit a triangular form in the broadest sense or else a circular-disk form, for example.
At least some portion of the bass reflex channel 70 can run within the second housing chamber 30 and be arranged there adjacent to the phase correction element 60. By way of example, the peripheral contour of the bass reflex channel 70 may match the contour of an outer wall section 60d or 60e of the phase correction element 60 or can have at least sections formed directly by the outer wall section 60d, 60e, as described.
The bass reflex channel 70 can also project—not shown—into the first housing chamber 20 over a certain depth. By way of example, this can be produced by virtue of a length of duct (not shown) projecting from the bass reflex opening 41 into the first housing chamber 20 in a manner known per se. In this case, the length of such a length of duct projecting into the first housing chamber 20 can be kept short, for example shorter than the length T1 of the bass reflex channel 70 in the second housing chamber 30. That is to say that the bass reflex channel frequently provided within the loudspeaker housing chamber 20 in conventional embodiments can be displaced in the loudspeaker housing 100 partially or completely into the second housing chamber 30, where it can be accommodated in space-saving fashion in a region that is acoustically shielded by the phase correction element 60 and hence represents a “dead” volume so to speak. In this case, as already described, outer wall sections 60d, 60e of the phase correction element 60 can be used to bound the bass reflex channel 70, which additionally allows a saving on material to be attained.
Housing chambers and bass reflex channels each form acoustic resonators. The first housing chamber 20 with its internal volume forms a first resonator of the loudspeaker housing 10. This first resonator interacts with the bass reflex resonator provided by the internal volume of the bass reflex channel. The combination of internal volume and geometry of the openings 41 determines the resonant frequency. The respective external volumes that immediately adjoin the front of the diaphragms 51 of the bass loudspeaker 50 form a second resonator. In this case, the effective volume and the effective opening area determine the resonant frequency. The effective volume and the effective opening area are significantly influenced by the geometry of the open second housing chamber 30 into which the bass loudspeaker radiates at the front. The external volume that the second resonator contains therefore likewise produces a resonance and prompts moderate low-pass filtering of the radiated sound. The low-pass filtering is accompanied by a slight sound level increase.
Without the phase correction element, the second resonator would be able to be used only in a frequency range below its fundamental resonance. Above the fundamental resonance, discrete modes that impair the sound are usually established. The flat phase correction element 60 arranged inside the second housing chamber 30 and hence inside the second resonator is used to decrease the mode acuity of the second resonator, so that the latter can also be used in a frequency range above its fundamental frequency. The physical (spatial) radiation response of the loudspeaker system 100 is influenced by the flat phase correction element 60 (unlike in the case of an acoustic lens) only little or not at all, for example.
As explained with reference to
The loudspeaker system 100 explained by way of example with reference to
In other words, the arrangement of phase correction element 60, opening 41 and partition 40, and the form of the bass reflex channel 70 adjacent to the phase correction element 60, may be produced in the same manner as has already been described for the loudspeaker system 100. To avoid repetition, reference is made to the description above. However, the oblique installation of the partition 40 allows the use of a bass loudspeaker 50 having a greater diameter for a prescribed height H of the loudspeaker housing 10, or else a decrease in the height H of the loudspeaker housing 10 for a prescribed diameter of the bass loudspeaker 50.
In addition,
In the loudspeaker system 300, a respective phase correction element 60 or 60′ is arranged at the front of the two bass loudspeakers 50, 50′ in the manner already described. In addition, bass reflex openings 41 and 41′ in the respective partitions 40 and 40′ between the first housing chamber 20 and the second housing chamber 30 and between the first housing chamber 20 and the third housing chamber 30′ are provided. The bass reflex openings 41 and 41′ open into the second housing chamber 30 and the third housing chamber 30′, respectively, in a region adjacent to the respective phase correction elements 60, 60′, see the description above.
As can be seen from the Figures, the two partitions 40, 40′ may both be installed in the loudspeaker housing 10 at an inclination, as has been explained previously with reference to
The loudspeaker system 300 may also have a further loudspeaker, e.g. a horn loudspeaker 80. The horn loudspeaker 80 may be situated between the two bass loudspeakers 50, 50′. A horn 81 of the horn loudspeaker 80 can take up a large part of or practically the whole region between the two partitions 40, 40′, for example. As can be seen from
The effect that can be achieved by the arrangement with the respective oblique installation of the bass loudspeakers 50, 50′ —as explained by way of example with reference to FIGS. 9 to 11—is that the loudspeaker housing 10 has a comparatively small height overall and the distance between the centers of the sound radiation from the two bass loudspeakers 50, 50′ is kept comparatively short. The formation of the bass reflex resonators (bass reflex channels 70, 70′) allows the volume of the respective bass reflex resonators to be largely or completely displaced, in the manner already described, into a space that is present on the outside or back of the respective phase correction element 60, 60′, which space, as a “dead” volume, would otherwise have practically no acoustic function.
The physical height of the loudspeaker housing 10 shown in
The form shown in
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German Office action, 6 pages, dated Jul. 25, 2014. |
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