Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2807—Enclosures comprising vibrating or resonating arrangements
  • H04R1/2853—Enclosures comprising vibrating or resonating arrangements using an acoustic labyrinth or a transmission line
  • H04R1/2857—Enclosures comprising vibrating or resonating arrangements using an acoustic labyrinth or a transmission line for loudspeaker transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
  • H04R1/2884—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure
  • H04R1/2888—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure for loudspeaker transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/227—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  using transducers reproducing the same frequency band
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/26—Spatial arrangements of separate transducers responsive to two or more frequency ranges
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
  • H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
  • H04R1/2876—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding
  • H04R1/288—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of damping material, e.g. as cladding for loudspeaker transducers

Definitions

• the invention relates to a loudspeaker device.
• Loudspeaker devices are known in many embodiments. It is generally known that the housing in which a woofer is arranged has a dominating influence on the fidelity of reproduction with which sound can be generated by the loudspeaker device.
• a loudspeaker device comprising: a generally tubular housing having a cavity which is closed at a first end and open at a second end; and at least one woofer placed in an opening in the wall of this housing; which cavity comprises seven rotation- symmetrical mutually connecting spaces, which spaces have substantially the same shape and a common axis of symmetry; which spaces have corresponding linear dimensions from the first to the second end with substantially the following respective ratios: (1) 0.53
• each space has a generally spherical shape.
• each space has the shape of a semi-ellipsoid of revolution directed toward the first end and a semi- spherical shape directed toward the second end, wherein the relative axial lengths of said two shapes are substantially in a ratio of 9:7.
• a preferred embodiment is herein characterized in that the necks have diameters which are 0.5 to 0.8 times the largest diameter of the adjacent spaces.
• An embodiment wherein the housing consists predominantly of concrete has the advantage that the housing has a great density and a correspondingly large mass and that there is no danger of unintended co- vibration of the housing.
• the cavity is lined with a layer consisting of a mixture of bitumen and rubber.
• damping is also obtained for very high frequencies.
• An embodiment is generally recommended in which the layer has a thickness of 1-6 mm.
• a preferred embodiment has the special feature that the woofer is arranged in a hole in the wall of the third space.
• the loudspeaker device according to the invention requires no internal damping.
• the invention nevertheless also provides a variant in which the first and the second spaces are filled with porous damping material, such as mineral wool.
• This variant is preferably characterized in that about ten times as much damping material is present in the first space as in the second space.
• the embodiment can serve in which the length of the cavity corresponds with the resonance frequency of the built-in woofer.
• a very fine directivity pattern of substantially monopole character is obtained with an embodiment comprising two symmetrically placed woofers facing away from each other. Another embodiment is provided with a tweeter, for instance a dome tweeter, placed in the vicinity of the woofer.
• a tweeter for instance a dome tweeter
• a specific embodiment has the special feature that the woofer and the tweeter are in phase linear arrangement. Such an embodiment is very simple to realize with a variant in which the woofer connects to the third space and the tweeter is situated in the region of the second space.
• Figure 1 shows a cross section through a loudspeaker device according to the invention in a first embodiment
• Figure 2 shows a perspective view of the device of figure 1;
• Figure 3 shows a partial cross section, corresponding with figure 1, of a variant
• Figure 4 shows a cross section through yet another embodiment
• Figure 5 shows a connection diagram for the loudspeakers
• Figure 6 shows an alternative connection diagram for the loudspeakers.
• Figure 1 shows a loudspeaker device 1. This comprises a generally tubular concrete housing 2 with a cavity 3 which is closed at the upper end and open at the lower end, in addition to two woofers 4, 5 placed in openings in the wall of this housing.
• the cavity 3 comprises seven rotation- symmetrical, mutually connecting, substantially spherical spaces 6, 7, 8, 9, 10, 11, 12 respectively. These spaces 6-12 have a common axis of symmetry which corresponds with the longitudinal axis of cavity 3.
• the spaces 6-12 have diameters with substantially the following respective ratios: 0.53 - 0.80 - 1.00 - 0.89 - 0.75 - 0.67 - 0.60.
• adjacent spaces mutually connect via necks, respectively 13, 14, 15, 16, 17, 18 with smooth rounded shapes.
• the space 12 debouches into the outside space via a neck 19 with a shape widening toward the outside.
• the cavity 3 is lined with a layer 20 consisting of bitumen mixed with rubber granules.
• Damping material is arranged in the spaces 6 and 7.
• the quantity of damping material in space 6 amounts to about ten times the quantity in space 7.
• the damping material can for instance be natural or mineral wool.
• the internal form of the device 1 is also reflected in the external design.
• the spaces 6-12 are enclosed by a wall having approximately the same thickness everywhere.
• the form shown in figure 2 which has the general appearance of a column consisting of spheres stacked one on top of anoth- er.
• the loudspeakers 4 and 5 are directed away from each other and are connected in phase, so that loudspeaker device 1 has a substantially monopole character, at least up to a frequency determined by the dimensions of the loudspeakers.
• the woofers 4, 5 are arranged in the region of the space 8. Placed in the region of the space 7 above the loudspeakers 4, 5 are tweeters respectively 21, 22. This placing is embodied such that the arrangement is phase linear relative to the woofers 4, 5. It must be understood in this respect that it may be desirable to give the radiation front of the loudspeaker a certain incline.
• the housing 2 further comprises a foot flange
• the loudspeaker device 1 is of the so-called "open* 1 type, which is desirable for reasons of quality.
• Figure 4 shows a variant wherein a loudspeaker device 23 has a housing 24 which on the outside does not follow the internal contours but has a more or less flat outer form.
• the drawback of this embodiment is that it is comparatively heavy.
• the properties of such a device 23 are otherwise in principle the same as those according to figures 1 and 2.
• the housing 24 can also have a rotation- symmetrical outer appearance. Attention is drawn to the fact that the basic shapes of the spaces 6-12 are imaginary spheres which substantially mutually tangential in the region of said necks 13-18.
• the necks have diameters which are 0.5 - 0.8 times the largest diameter of the adjacent spaces.
• FIG 3 shows a variant 25 wherein a housing 26 is embodied such that the spaces 27, 28 do not have a spherical shape but each have a general egg shape.
• the relevant contours are drawn schematically in full lines in figure 3.
• each of the spaces 27, 28 is rotation- symmetrical.
• Each space has the shape of a semi-ellipsoid of revolution directed toward the closed end and a semi- spherical shape directed toward the open end.
• the axial lengths of said two shapes are substantially in a ratio of 9:7.
• Figures 5 and 6 show possible connection diagrams for the loudspeakers.
• the loudspeakers 4, 5 are of the type which have a natural attenuation for the higher frequencies, for instance because the cone is covered with a neoprene rubber layer.
• the dome tweeters 21, 22 take over the sound-radiating function from the natural cross-over frequency of the woofers.
• the relevant take-over frequen- cy is determined by the impedance of loudspeakers 21, 22 and a series capacitor 29.

Landscapes

• Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
• Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19865682

Family Applications (1)

Country Status (4)

Citations (9)

• 1995
  • 1995-03-06 NL NL9500440A patent/NL9500440A/nl not_active Application Discontinuation
• 1996
  • 1996-03-06 AU AU48502/96A patent/AU4850296A/en not_active Abandoned
  • 1996-03-06 WO PCT/NL1996/000104 patent/WO1996027999A1/en not_active Application Discontinuation
  • 1996-03-06 EP EP96904382A patent/EP0876740A1/en not_active Withdrawn

Patent Citations (9)

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