Loudspeaker enclosure with enhanced bass response

Abstract

A loudspeaker enclosure comprises a housing defining therein a principal volume having a front wall and a substantially smaller minor volume. The minor volume has a rear wall common to the front wall of the principal volume. The common wall defines a port which communicates the minor volume to the principal volume. A speaker mounting opening is defined in a front wall of the minor volume. The speaker mounting opening defines the only opening from the exterior of the housing to the interior thereof.

What is claimed is: 
     
       1. A loudspeaker enclosure comprising a housing defining therein a principal volume having a front wall .Iadd.providing a front boundary of the principal volume .Iaddend.and a substantially smaller minor volume having a rear . .wall.!. .Iadd.boundary .Iaddend.common to the front . .wall.!. .Iadd.boundary .Iaddend.of the principal volume, . .the common.!. .Iadd.said front .Iaddend.wall defining a port communicating the minor volume only to the principal volume, .Iadd.the principal volume front boundary having selected height and width dimensions, the principal volume also being of selected depth in a direction perpendicular to its front wall, the minor volume at its rear boundary having height and width dimensions which are less than and are in directions respectively parallel to the height and width dimensions of the principal volume front boundary, .Iaddend.and a speaker mounting opening defined in a front wall of the minor volume, the mounting opening defining the only opening from the exterior of the housing to the interior thereof, and in which the speaker mounting opening opens essentially directly from the interior of the enclosure to the exterior thereof. 
     
     
       2. A loudspeaker enclosure according to claim 1 wherein the minor volume is substantially centered on the front wall of the principal volume. 
     
     
       3. A loudspeaker enclosure according to claim 1 wherein the port is substantially centered in the rear . .wall.!. .Iadd.boundary .Iaddend.of the minor volume. 
     
     
       4. A loudspeaker enclosure according to claim 1 wherein the minor volume is substantially centered on the front wall of the principal volume and the port is substantially centered in the front wall of the principal volume. 
     
     
       5. A loudspeaker enclosure according to claim 1 wherein the ratio of the minor volume to the principal volume is in the range of from about 0.120 to about 0.250. 
     
     
       6. A loudspeaker enclosure according to claim 1 including a quantity of acoustical packing material in the principal volume over the area of a rear wall of the principal volume and extending at least partially toward the principal volume front wall. 
     
     
       7. A loudspeaker enclosure according to claim 6 wherein the packing material extends only partially toward the principal volume front wall, and including a membrane substantially impermeable to air disposed across the surface of the packing material adjacent said front wall. 
     
     
       8. A loudspeaker enclosure according to claim 1 wherein the principal volume is of generally rectilinear configuration. 
     
     
       9. A loudspeaker enclosure according to claim 1 wherein the minor volume is of generally rectilinear configuration. 
     
     
       10. A loudspeaker enclosure according to claim 1 wherein the principal and minor volumes are both of generally rectilinear configuration. 
     
     
       11. A loudspeaker enclosure according to claim 1 wherein the minor volume has all dimensions thereof smaller than the corresponding dimensions of the principal volume. 
     
     
       12. A loudspeaker enclosure according to claim 1 wherein the ratio of the area of the port to the area of the principal volume front . .wall.!. .Iadd.boundary .Iaddend.is in the range of from about 0.24 to about 0.28. 
     
     
       13. A loudspeaker enclosure according to claim 1 wherein the ratio of the diameter of the speaker mounting opening to the diameter of the port is in the range of from about 0.75 to about 0.90. .Iadd. 14. A loudspeaker enclosure comprising for each loudspeaker mountable to the enclosure, a primary chamber defining a principal interior volume and a secondary chamber defining a minor interior volume substantially smaller than the principal interior volume, the primary chamber having a front wall with outer and inner faces, the inner face forming a front boundary of selected height and width dimensions for the principal volume, the secondary chamber being defined by an elongated housing essentially permanently sealed to the front wall of the primary chamber and projecting beyond one of the faces of the primary chamber front wall, said housing defining a speaker mounting opening which opens essentially directly to the exterior of the enclosure from a front boundary of the minor volume, said housing defining a second simple opening disposed substantially coaxial with the speaker mounting opening at a rear boundary of the minor volume and which opens through the minor volume rear boundary to the principal volume, the second opening providing simple and direct communication between the principal and minor volumes, the minor volume at the second opening having height and width dimensions which are less than and are in directions respectively parallel to the height and width dimensions of the principal volume front boundary. .Iaddend. .Iadd. 15. A loudspeaker enclosure comprising a housing, the housing being comprised, for each loudspeaker mountable to the enclosure, of a principal chamber structure defining therein a principal interior volume of the enclosure and having a front wall defining therein a first simple opening, the principal volume front wall forming a principal volume front boundary having selected dimensions of height and width, the housing also being comprised of a minor chamber structure defining therein a minor interior volume of the enclosure which is substantially smaller than the principal volume, the minor chamber structure being essentially permanently mounted to the principal structure front wall in association with the first opening, the minor chamber structure defining a second simple opening substantially coaxial with the first opening, the one of the first and second openings which is most outwardly of the principal volume comprising a speaker mounting opening which opens essentially directly from the interior of the enclosure to the exterior thereof and which is the only opening from the interior of the housing to the exterior thereof, the minor chamber structure being so mounted to the principal structure that the principal and minor volumes are in direct and simple communication with each other only via the other of the first and second openings, said other of the openings defining a rear boundary of the minor volume at which the minor volume has dimensions of height and width which are less than and are directions respectively parallel to the height and width dimensions of the principal volume. .Iaddend.