CA2826710A1 - Loudspeaker enclosure - Google Patents
Loudspeaker enclosure Download PDFInfo
- Publication number
- CA2826710A1 CA2826710A1 CA 2826710 CA2826710A CA2826710A1 CA 2826710 A1 CA2826710 A1 CA 2826710A1 CA 2826710 CA2826710 CA 2826710 CA 2826710 A CA2826710 A CA 2826710A CA 2826710 A1 CA2826710 A1 CA 2826710A1
- Authority
- CA
- Canada
- Prior art keywords
- loudspeaker enclosure
- aperture
- loudspeaker
- enclosure
- diaphragm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000005236 sound signal Effects 0.000 claims abstract description 14
- 239000012528 membrane Substances 0.000 claims abstract description 12
- 230000005540 biological transmission Effects 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 description 8
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011094 fiberboard Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
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
- H04R1/2869—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
Landscapes
- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Details Of Audible-Bandwidth Transducers (AREA)
Abstract
A loudspeaker enclosure is provided. The loudspeaker enclosure comprises a wall structure having an opening for enabling transmission of a sound signal therethrough with the sound signal being generated by a diaphragm of a loudspeaker driver disposed inside the loudspeaker enclosure. The wall structure further has an aperture disposed therein. A
membrane covers an inside end of the aperture in a substantially sealed fashion.
membrane covers an inside end of the aperture in a substantially sealed fashion.
Description
LOUDSPEAKER ENCLOSURE
FIELD OF THE INVENTION
The present invention relates to a loudspeaker enclosure, and more particularly to a loudspeaker enclosure having a noise interference reducing structure.
BACKGROUND OF THE INVENTION
The primary role of the loudspeaker enclosure is to prevent sound waves generated by the rearward-facing surface of the diaphragm of an open driver from interacting with sound waves generated by the forward-facing surface of the diaphragm. Since the forward-and rearward-generated sound waves are out of phase with each other, any interaction between the two in the listening space creates a distortion of the original sound signal generated by the forward-facing surface of the diaphragm. Additionally, since the forward- and rearward-generated sound waves travel different paths, the sound waves arrive at the listener's location at slightly different times, introducing complex echo and reverberation effects that will very likely interfere with the original signal Unfortunately, loudspeaker enclosures can generate significant noise interference disturbing the original sound signal. The rearward-generated sound waves interact with the enclosure generating acoustic and mechanical resonances in the enclosure and acoustic reflections/diffractions from the inside walls of the enclosure which impede the driver's movement - distorting the generation of the original sound signal - and, furthermore, are transmitted through the diaphragm ¨ resulting in a superposition with the original sound signal.
Numerous attempts have been made to reduce the noise interference inside the loudspeaker enclosure as well as within the structure/body of the loudspeaker enclosure such as, for example, selection of various materials used for the enclosure to increase mass and/or stiffness, as well as disposing various materials inside the enclosure to provide internal absorption. Unfortunately, these attempts generally provided only a limited reduction of the noise interference and/or are Page 1 of 9 very expensive to implement.
Furthermore, to ensure proper performance of the driver it is often desired to have a predetermined airload acting on the rearward-facing surface of the diaphragm.
It is desirable to provide a loudspeaker enclosure that has substantially reduced noise interference.
It is also desirable to provide a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
It is also desirable to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference.
Another object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
Another object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
According to one aspect of the present invention, there is provided a loudspeaker enclosure. The loudspeaker enclosure comprises a wall structure having an opening for enabling transmission of a sound signal therethrough with the sound signal being generated by a diaphragm of a loudspeaker driver disposed inside the loudspeaker enclosure. The wall structure further has an aperture disposed therein. A membrane covers an inside end of the aperture in a substantially Page 2 of 9 sealed fashion.
The advantage of the present invention is that it provides a loudspeaker enclosure that has substantially reduced noise interference.
A further advantage of the present invention is that it provides a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
A further advantage of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which:
Figures la and lb are simplified block diagrams illustrating a perspective view and a cross sectional view, respectively, of a loudspeaker enclosure according to a preferred embodiment of the invention;
Figures lc and 1 d are simplified block diagrams illustrating a perspective outside and perspective inside view, respectively, of a corner of the loudspeaker enclosure according to a preferred embodiment of the invention; and, Figures 2a to 2d are simplified block diagrams illustrating a cross sectional view of an aperture of the loudspeaker enclosure according to a preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Page 3 of 9 i , Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.
Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.
While the description of the preferred embodiments hereinbelow is with reference to a loudspeaker enclosure having rectangular walls, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for differently shaped loudspeaker enclosures.
Furthermore, while the description of the preferred embodiments hereinbelow is with reference to a sealed loudspeaker enclosure, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for other types of loudspeaker enclosures that produce an acoustic pressure point within the enclosure when interacting with the rearward generated sound waves produced by the driver diaphragm resulting in a noticeable reduction of the noise interference.
Furthermore, while the description of the preferred embodiments hereinbelow is with reference to tuning to the resonance frequency of the loudspeaker enclosure, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for tuning to other frequencies that produce an acoustic pressure point within the loudspeaker enclosure when interacting with the rearward generated sound waves produced by the driver diaphragm resulting in a noticeable reduction of the noise interference.
Referring to Figures la to ld, a loudspeaker enclosure 100 according to a preferred embodiment of the invention is provided. The loudspeaker enclosure 100 comprises at least one aperture 102 disposed in the wall structure 100A, 100B, 100C thereof. The aperture 102 extends from the inside of the loudspeaker enclosure 100 to the outside. An inside end of the aperture 102 is covered by membrane 106 in a substantially sealed fashion, as illustrated in Figure ld and as will be described in more detail hereinbelow.
Page 4 of 9 , In operation, a sound signal is generated by movement of diaphragm 12 of loudspeaker driver 10 disposed inside the loudspeaker enclosure 100 and transmitted through opening 101 disposed in the wall structure 100A of the loudspeaker enclosure 100. The primary role of the loudspeaker enclosure 100 is to prevent sound waves generated by the rearward-facing surface of the diaphragm 12 ¨ facing the inside of the of the loudspeaker enclosure 100 ¨
from interacting with sound waves generated by the forward-facing surface of the diaphragm 12 ¨
facing the outside.
As is well known in the art, loudspeaker enclosures can generate significant noise interference disturbing the original sound signal. The rearward-generated sound waves interact with the loudspeaker enclosure generating acoustic resonances in the structure of the enclosure and acoustic reflections/diffractions from the inside surface of the loudspeaker enclosure which impede the driver's movement - distorting the generation of the original sound signal - and, furthermore, are transmitted through the diaphragm ¨ resulting in a superposition with the original sound signal. Therefore, the main objective of present day loudspeaker enclosure design is to substantially reduce the noise interference while still providing airload acting on the rearward-facing surface of the diaphragm 12.
This objective is achieved in the loudspeaker enclosure 100 by transmitting acoustic energy generated by the rearward-facing surface of the diaphragm 12 through the aperture 102 to the outside, with the transmission being substantially limited to one direction ¨
i.e. from the inside of the loudspeaker enclosure 100 to the outside ¨ and , preferably, to acoustic energy at a frequency being approximately the fundamental frequency of the entire loudspeaker enclosure 100, i.e. the lowest frequency at which the entire loudspeaker enclosure 100 resonates. The size of the aperture 102 is determined such that the acoustic impedance of the airmass inside the aperture 102 has sufficient stiffness for preventing transmission of acoustic energy therethrough and a resonance frequency being approximately the fundamental frequency of the loudspeaker enclosure 100. The membrane 106 is determined to have a resonance frequency corresponding to the resonance frequency of the airmass inside the aperture 102 to enable transmission of acoustic energy through the aperture 102 at the resonance frequency. Placing of the membrane 106 to cover the inside end of the aperture 102 ensures that the transmission of the acoustic energy is substantially limited to the direction from the inside of the loudspeaker enclosure 100 to the Page 5 of 9 outside. One skilled in the art can readily determine the size of the aperture 102 in dependence upon the loudspeaker driver employed and the volume and the stiffness of the loudspeaker enclosure 100, as well as the size, material, and tension of the membrane 106.
It is noted that, while it is preferred to transmit the acoustic at the fundamental frequency of the entire loudspeaker enclosure 100, it is possible to achieve a reduction of noise interference by transmitting the acoustic energy at other frequencies that produce an acoustic pressure point inside the enclosure when interacting with the rearward generated soundwave of the driver.
Preferably, the aperture 102 is disposed in a corner ¨ detail A - of the loudspeaker enclosure 100, as illustrated in Figures 1 c and ld, and further preferably, is oriented along a line connecting the inside corner with the outside corner, as illustrated in the cross sectional view in plane 104 of Figures 2a to 2d. Placing the aperture 102 in the corner is preferred, since the loudspeaker enclosure 100 is stiffest in the corner and the pressure ¨ mechanical and acoustic ¨ is the highest in the corner. Alternatively, the aperture 102 is disposed at a different location, for example, in proximity to the corner, or has a different orientation, for example, oriented from the inside corner to a location in proximity to the outside corner.
While, it is further preferred to dispose eight apertures 102 in the loudspeaker enclosure 100 with one aperture 102 in each corner thereof, the invention is not limited thereto, but different numbers of apertures are employable, for example, four apertures 102 disposed in the back corners of the loudspeaker enclosure 100. Even a single aperture 102 provides a noticeable reduction of the noise interference.
As illustrated in Figures 2a, a pyramidal shaped corner member 108 substantially conforming to the inside corner of the loudspeaker enclosure 100 is disposed therein and mounted to the inside surface thereof using, for example, an adhesive. A bore forming the aperture 102 is then drilled through the corner member 108 and the loudspeaker enclosure 100 from the inside corner to the outside corner. The corner member 108 provides contact surface 110 for mounting the membrane 106 thereto to cover the inside end of the aperture 102 in a substantially sealed fashion using a suitable adhesive.
Page 6 of 9 =
Optionally, as illustrated in Figure 2b, the cross section of the aperture 102 is increased towards the outside end forming a horn like structure for improving the acoustic impedance match between the air in the aperture 102 and the outside air. The horn like structure is provided, for example, by beveling 112 the outside end portion of the aperture 102. Of course, various other shapes are implementable such as, for example, increasing the cross section from the inside end to the outside end of the aperture 102 in a linear or curved fashion.
Alternatively, as illustrated in Figure 2c, the bore forming the aperture 102 is countersunk 114 to provide the contact surface 110 for the membrane 106.
Further alternatively, as illustrated in Figure 2d, a tube 116 comprising the aperture 102 is disposed in the loudspeaker enclosure 100. The membrane 106 is then mounted to an end portion of the tube 116 using, for example, a suitable adhesive. Preferably, the tube is made of a substantially stiff material such as, for example, a metal.
As is evident, the invention is also implementable by providing an aperture 102 having a cross section other than circular such as, for example, oval or rectangular.
In an exemplary implementation, a loudspeaker enclosure made of Medium Density Fiberboard (MDF) and having a wall thickness of approximately 7mm was used. The invention was implemented using off-the-shelf materials and standard manufacturing methods.
The aperture 102 ¨ having a circular cross section ¨ was provided by drilling a bore with a diameter of 0.71mm (# 70 drill bit) from the inside corner to the outside corner. The contact surface 110 was provided using a corner member 108 made of MDF. The membrane 106 was implemented using a Teflon tape ¨ 3M Type 63 or 60 PTFE. It is noted that the membrane 106 is implementable using various types of sheet materials that have sufficient flexibility and resonate at the resonance frequency of the airmass in the aperture 102.
The present invention has been described herein with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.
Page 7 of 9
FIELD OF THE INVENTION
The present invention relates to a loudspeaker enclosure, and more particularly to a loudspeaker enclosure having a noise interference reducing structure.
BACKGROUND OF THE INVENTION
The primary role of the loudspeaker enclosure is to prevent sound waves generated by the rearward-facing surface of the diaphragm of an open driver from interacting with sound waves generated by the forward-facing surface of the diaphragm. Since the forward-and rearward-generated sound waves are out of phase with each other, any interaction between the two in the listening space creates a distortion of the original sound signal generated by the forward-facing surface of the diaphragm. Additionally, since the forward- and rearward-generated sound waves travel different paths, the sound waves arrive at the listener's location at slightly different times, introducing complex echo and reverberation effects that will very likely interfere with the original signal Unfortunately, loudspeaker enclosures can generate significant noise interference disturbing the original sound signal. The rearward-generated sound waves interact with the enclosure generating acoustic and mechanical resonances in the enclosure and acoustic reflections/diffractions from the inside walls of the enclosure which impede the driver's movement - distorting the generation of the original sound signal - and, furthermore, are transmitted through the diaphragm ¨ resulting in a superposition with the original sound signal.
Numerous attempts have been made to reduce the noise interference inside the loudspeaker enclosure as well as within the structure/body of the loudspeaker enclosure such as, for example, selection of various materials used for the enclosure to increase mass and/or stiffness, as well as disposing various materials inside the enclosure to provide internal absorption. Unfortunately, these attempts generally provided only a limited reduction of the noise interference and/or are Page 1 of 9 very expensive to implement.
Furthermore, to ensure proper performance of the driver it is often desired to have a predetermined airload acting on the rearward-facing surface of the diaphragm.
It is desirable to provide a loudspeaker enclosure that has substantially reduced noise interference.
It is also desirable to provide a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
It is also desirable to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference.
Another object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
Another object of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
According to one aspect of the present invention, there is provided a loudspeaker enclosure. The loudspeaker enclosure comprises a wall structure having an opening for enabling transmission of a sound signal therethrough with the sound signal being generated by a diaphragm of a loudspeaker driver disposed inside the loudspeaker enclosure. The wall structure further has an aperture disposed therein. A membrane covers an inside end of the aperture in a substantially Page 2 of 9 sealed fashion.
The advantage of the present invention is that it provides a loudspeaker enclosure that has substantially reduced noise interference.
A further advantage of the present invention is that it provides a loudspeaker enclosure that has substantially reduced noise interference while providing an airload acting on the rearward-facing surface of the diaphragm.
A further advantage of the present invention is to provide a loudspeaker enclosure that has substantially reduced noise interference and is manufactured at substantially reduced cost.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which:
Figures la and lb are simplified block diagrams illustrating a perspective view and a cross sectional view, respectively, of a loudspeaker enclosure according to a preferred embodiment of the invention;
Figures lc and 1 d are simplified block diagrams illustrating a perspective outside and perspective inside view, respectively, of a corner of the loudspeaker enclosure according to a preferred embodiment of the invention; and, Figures 2a to 2d are simplified block diagrams illustrating a cross sectional view of an aperture of the loudspeaker enclosure according to a preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Page 3 of 9 i , Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.
Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.
While the description of the preferred embodiments hereinbelow is with reference to a loudspeaker enclosure having rectangular walls, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for differently shaped loudspeaker enclosures.
Furthermore, while the description of the preferred embodiments hereinbelow is with reference to a sealed loudspeaker enclosure, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for other types of loudspeaker enclosures that produce an acoustic pressure point within the enclosure when interacting with the rearward generated sound waves produced by the driver diaphragm resulting in a noticeable reduction of the noise interference.
Furthermore, while the description of the preferred embodiments hereinbelow is with reference to tuning to the resonance frequency of the loudspeaker enclosure, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable for tuning to other frequencies that produce an acoustic pressure point within the loudspeaker enclosure when interacting with the rearward generated sound waves produced by the driver diaphragm resulting in a noticeable reduction of the noise interference.
Referring to Figures la to ld, a loudspeaker enclosure 100 according to a preferred embodiment of the invention is provided. The loudspeaker enclosure 100 comprises at least one aperture 102 disposed in the wall structure 100A, 100B, 100C thereof. The aperture 102 extends from the inside of the loudspeaker enclosure 100 to the outside. An inside end of the aperture 102 is covered by membrane 106 in a substantially sealed fashion, as illustrated in Figure ld and as will be described in more detail hereinbelow.
Page 4 of 9 , In operation, a sound signal is generated by movement of diaphragm 12 of loudspeaker driver 10 disposed inside the loudspeaker enclosure 100 and transmitted through opening 101 disposed in the wall structure 100A of the loudspeaker enclosure 100. The primary role of the loudspeaker enclosure 100 is to prevent sound waves generated by the rearward-facing surface of the diaphragm 12 ¨ facing the inside of the of the loudspeaker enclosure 100 ¨
from interacting with sound waves generated by the forward-facing surface of the diaphragm 12 ¨
facing the outside.
As is well known in the art, loudspeaker enclosures can generate significant noise interference disturbing the original sound signal. The rearward-generated sound waves interact with the loudspeaker enclosure generating acoustic resonances in the structure of the enclosure and acoustic reflections/diffractions from the inside surface of the loudspeaker enclosure which impede the driver's movement - distorting the generation of the original sound signal - and, furthermore, are transmitted through the diaphragm ¨ resulting in a superposition with the original sound signal. Therefore, the main objective of present day loudspeaker enclosure design is to substantially reduce the noise interference while still providing airload acting on the rearward-facing surface of the diaphragm 12.
This objective is achieved in the loudspeaker enclosure 100 by transmitting acoustic energy generated by the rearward-facing surface of the diaphragm 12 through the aperture 102 to the outside, with the transmission being substantially limited to one direction ¨
i.e. from the inside of the loudspeaker enclosure 100 to the outside ¨ and , preferably, to acoustic energy at a frequency being approximately the fundamental frequency of the entire loudspeaker enclosure 100, i.e. the lowest frequency at which the entire loudspeaker enclosure 100 resonates. The size of the aperture 102 is determined such that the acoustic impedance of the airmass inside the aperture 102 has sufficient stiffness for preventing transmission of acoustic energy therethrough and a resonance frequency being approximately the fundamental frequency of the loudspeaker enclosure 100. The membrane 106 is determined to have a resonance frequency corresponding to the resonance frequency of the airmass inside the aperture 102 to enable transmission of acoustic energy through the aperture 102 at the resonance frequency. Placing of the membrane 106 to cover the inside end of the aperture 102 ensures that the transmission of the acoustic energy is substantially limited to the direction from the inside of the loudspeaker enclosure 100 to the Page 5 of 9 outside. One skilled in the art can readily determine the size of the aperture 102 in dependence upon the loudspeaker driver employed and the volume and the stiffness of the loudspeaker enclosure 100, as well as the size, material, and tension of the membrane 106.
It is noted that, while it is preferred to transmit the acoustic at the fundamental frequency of the entire loudspeaker enclosure 100, it is possible to achieve a reduction of noise interference by transmitting the acoustic energy at other frequencies that produce an acoustic pressure point inside the enclosure when interacting with the rearward generated soundwave of the driver.
Preferably, the aperture 102 is disposed in a corner ¨ detail A - of the loudspeaker enclosure 100, as illustrated in Figures 1 c and ld, and further preferably, is oriented along a line connecting the inside corner with the outside corner, as illustrated in the cross sectional view in plane 104 of Figures 2a to 2d. Placing the aperture 102 in the corner is preferred, since the loudspeaker enclosure 100 is stiffest in the corner and the pressure ¨ mechanical and acoustic ¨ is the highest in the corner. Alternatively, the aperture 102 is disposed at a different location, for example, in proximity to the corner, or has a different orientation, for example, oriented from the inside corner to a location in proximity to the outside corner.
While, it is further preferred to dispose eight apertures 102 in the loudspeaker enclosure 100 with one aperture 102 in each corner thereof, the invention is not limited thereto, but different numbers of apertures are employable, for example, four apertures 102 disposed in the back corners of the loudspeaker enclosure 100. Even a single aperture 102 provides a noticeable reduction of the noise interference.
As illustrated in Figures 2a, a pyramidal shaped corner member 108 substantially conforming to the inside corner of the loudspeaker enclosure 100 is disposed therein and mounted to the inside surface thereof using, for example, an adhesive. A bore forming the aperture 102 is then drilled through the corner member 108 and the loudspeaker enclosure 100 from the inside corner to the outside corner. The corner member 108 provides contact surface 110 for mounting the membrane 106 thereto to cover the inside end of the aperture 102 in a substantially sealed fashion using a suitable adhesive.
Page 6 of 9 =
Optionally, as illustrated in Figure 2b, the cross section of the aperture 102 is increased towards the outside end forming a horn like structure for improving the acoustic impedance match between the air in the aperture 102 and the outside air. The horn like structure is provided, for example, by beveling 112 the outside end portion of the aperture 102. Of course, various other shapes are implementable such as, for example, increasing the cross section from the inside end to the outside end of the aperture 102 in a linear or curved fashion.
Alternatively, as illustrated in Figure 2c, the bore forming the aperture 102 is countersunk 114 to provide the contact surface 110 for the membrane 106.
Further alternatively, as illustrated in Figure 2d, a tube 116 comprising the aperture 102 is disposed in the loudspeaker enclosure 100. The membrane 106 is then mounted to an end portion of the tube 116 using, for example, a suitable adhesive. Preferably, the tube is made of a substantially stiff material such as, for example, a metal.
As is evident, the invention is also implementable by providing an aperture 102 having a cross section other than circular such as, for example, oval or rectangular.
In an exemplary implementation, a loudspeaker enclosure made of Medium Density Fiberboard (MDF) and having a wall thickness of approximately 7mm was used. The invention was implemented using off-the-shelf materials and standard manufacturing methods.
The aperture 102 ¨ having a circular cross section ¨ was provided by drilling a bore with a diameter of 0.71mm (# 70 drill bit) from the inside corner to the outside corner. The contact surface 110 was provided using a corner member 108 made of MDF. The membrane 106 was implemented using a Teflon tape ¨ 3M Type 63 or 60 PTFE. It is noted that the membrane 106 is implementable using various types of sheet materials that have sufficient flexibility and resonate at the resonance frequency of the airmass in the aperture 102.
The present invention has been described herein with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.
Page 7 of 9
Claims
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A loudspeaker enclosure comprising:
a wall structure having an opening for enabling transmission of a sound signal therethrough, the sound signal being generated by a diaphragm of a loudspeaker driver disposed inside the loudspeaker enclosure, the wall structure having an aperture disposed therein;
and, a membrane covering an inside end of the aperture in a substantially sealed fashion.
a wall structure having an opening for enabling transmission of a sound signal therethrough, the sound signal being generated by a diaphragm of a loudspeaker driver disposed inside the loudspeaker enclosure, the wall structure having an aperture disposed therein;
and, a membrane covering an inside end of the aperture in a substantially sealed fashion.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2826710 CA2826710A1 (en) | 2013-09-10 | 2013-09-10 | Loudspeaker enclosure |
| PCT/CA2014/000680 WO2015035503A1 (en) | 2013-09-10 | 2014-09-08 | Loudspeaker enclosure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2826710 CA2826710A1 (en) | 2013-09-10 | 2013-09-10 | Loudspeaker enclosure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2826710A1 true CA2826710A1 (en) | 2015-03-10 |
Family
ID=52664873
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2826710 Abandoned CA2826710A1 (en) | 2013-09-10 | 2013-09-10 | Loudspeaker enclosure |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2826710A1 (en) |
| WO (1) | WO2015035503A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5652801A (en) * | 1994-05-02 | 1997-07-29 | Aura Systems, Inc. | Resonance damper for piezoelectric transducer |
| US20050175206A1 (en) * | 2004-02-06 | 2005-08-11 | Deon Bearden | Loudspeaker assembly having a folded bifurcated vent tube |
| US20100142741A1 (en) * | 2004-05-12 | 2010-06-10 | Jan Princeton Plummer | Loudspeaker |
-
2013
- 2013-09-10 CA CA 2826710 patent/CA2826710A1/en not_active Abandoned
-
2014
- 2014-09-08 WO PCT/CA2014/000680 patent/WO2015035503A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015035503A1 (en) | 2015-03-19 |
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