Patent Publication Number: US-6704426-B2

Title: Loudspeaker system

Description:
This application is a continuation-in-part of U.S. Ser. No. 09/260,309, now U.S. Pat. No. 6,169,811 filed on Mar. 2, 1999 and U.S. patent application Ser. No. 09/505,553 filed Feb. 17, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     This invention relates to improved loudspeaker systems. In particular the invention relates to improved loudspeaker systems incorporating differential area passive radiators (DAPR) with more than two acoustic surface areas. 
     2. Prior Art 
     A group of prior art devices, relating to the invention, include Clarke U.S. Pat. No. 4,076,097, and Dusanek U.S. Pat. No. 4,301,332. These devices are well characterized in “Augmented Passive-Radiator Loudspeaker Systems, Parts 1 and 2” by Thomas L. Clarke, found in the June and July, 1981 issues of the Journal of the Audio Engineering Society. 
     Another device relating to the invention is found in Geddes PCT WO99/18755. The Geddes device is essentially a bandpass implementation of the Dusanek system. It is characterized in “The Acoustic Lever Loudspeaker Enclosure” found in the January/February 1999 issues of the Journal of the Audio Engineering Society. 
     These prior art devices configure their active transducers such that one side surface area is coupled through a chamber to one of three diaphragm surface areas of an augmented passive radiator (APR), which is also coupled to the outside environment at a second diaphragm surface area of the APR. An augmented passive radiator is defined as a passive dual cone radiator that has one surface area coupled through the main enclosure volume to the active transducer, a second surface area coupled to the outside environment and a third surface area enclosed in a sealed auxiliary chamber. The Dusanek and Clarke active transducers radiate into free space and the Geddes system operates as a bandpass with the second side of the active transducer coupled to a third internal chamber. Even with this difference all three systems still use the closed architecture approach of exposing only one of the three acoustic surface areas of the augmented passive radiator to the external environment while sealing off the two remaining surface areas into isolated internal chambers or, alternatively, not controlling the output of at least one of the two remaining surface areas through a predetermined opening. 
     It is also a limitation of these systems that the active transducer has only one side of its cone interacting with the augmented passive radiator and/or they also isolate the output of one of the surface areas of their augmented passive radiators into a sealed chamber so that only one surface area can generate acoustic output. To state it differently, an augmented passive radiator (or the equivalent acoustic lever as per Geddes) is a closed architecture system with an isolated auxiliary chamber that closes off the output and coupling of one of the two smaller coupling areas of the augmented passive radiator. The prior art closed architecture approaches limit the low frequency output capability and/or require a larger enclosure than the present invention. 
     A further limitation of the Geddes disclosure is that it only discloses the use of an augmented passive radiator in a series bandpass configuration which can be less favorable particularly for low transformation ratio alignments. 
     SUMMARY OF THE INVENTION 
     The present invention provides an enhanced acoustic output through the use of an open architecture application of a differential area passive radiator (hereafter referred to as DAPR) having three substantially separate acoustic surface areas. A large or primary acoustic surface area, a smaller or unitary surface area, and a second smaller or differential surface area. The DAPR can be realized with the combination of two loudspeaker cones of different sizes attached back to back, each having their own surround/suspension. Alternatively the DAPR can be realized with one loudspeaker cone with a surround/suspension at the large end of the cone opening and another surround/suspension at the small end of the cone opening. The front and/or the rear of the DAPR is blocked off to acoustically isolate the areas. The DAPR enhances the output of an active transducer by operating as an acoustic transformer with a coupling ratio of the active transducer diaphragm area to the coupled acoustic surface area of the DAPR and the further ratio of one of the smaller acoustic surface areas of the DAPR to the largest surface area of the DAPR. 
     As disclosed in the parent case this invention advances the art of low frequency output with a three surface area differential area passive radiator in a novel configuration to eliminate the limitations of a closed architecture augmented passive radiator or acoustic lever by using an open architecture configuration of one or more differential area passive radiators. 
     It was shown that the open architecture is created by using a differential area passive radiator that has at least two of its three surface areas coupled to both sides of the active transducer and/or has a first and largest of the differential area passive radiator&#39;s three surface areas output coupled into the listening environment either directly or indirectly through an opening of predetermined characteristics or passive acoustic radiator and a second of the differential area passive radiator&#39;s three surface areas at least partially coupled into the listening indirectly through a passive acoustic radiator or opening of predetermined characteristics. 
     The differential area passive radiator can provide excellent acoustic performance when more than one of its acoustic surfaces has a predetermined, at least partially open, pathway to the external environment. 
     Further disclosed in the parent cases of this invention is the use of a parallel transfer of acoustic energy with the active transducer coupling acoustically in parallel with the differential area passive radiator by being coupled to the differential coupling area of the DAPR as an alternative to coupling in series through the small or unitary diaphragm surface area of the differential area passive radiator. This parallel coupling can offer favorable construction advantages for a given set of alignments, particularly those with a DAPR transformation ratio of less than two to one. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a graphic representation of a prior art full range speaker with an augmented passive radiator as a vent/port substitute. 
     FIG. 2 shows graphic representation of another prior art full range speaker with an augmented passive radiator as a vent/port substitute. 
     FIG. 3 shows a graphic representation of a bandpass implementation of an augmented passive radiator. 
     FIG. 4 shows a graphic representation of a bandpass implementation with two augmented passive radiators. 
     FIG. 5A shows a graphic representation of a basic form of the invention in parallel interaction mode. 
     FIG. 5B shows a graphic representation of a basic form of the invention in series interaction mode. 
     FIG. 6A shows a graphic representation of a basic form of the invention with a vent. 
     FIG. 6B shows a graphic representation of another basic form of the invention with a vent. 
     FIG. 7A shows a graphic representation of the invention with the transducer coupled to a chamber which is coupled to a passive acoustic radiator and one surface of the differential area passive radiator coupled to a second chamber which is coupled to a passive acoustic radiator. 
     FIG. 7B shows a graphic representation of the invention with an alternative series construction to the system in FIG.  7 A. 
     FIG. 8A shows a graphic representation of an embodiment of a woofer system with a highly resistive vent. 
     FIG. 8B shows a graphic representation of an embodiment of a woofer system low resistance, flared vents. 
     FIG. 9A shows a graphic representation of a passive acoustic radiator illustrated as a vent opening. 
     FIG. 9B shows a graphic representation of a passive acoustic radiator illustrated as an extended port. 
     FIG. 9C shows a graphic representation of a passive acoustic radiator illustrated as an lossy resistive vent. 
     FIG. 9D shows a graphic representation of a passive acoustic radiator illustrated as a low loss extended port. 
     FIG. 9E shows a graphic representation of a passive acoustic radiator illustrated as a suspended passive diaphragm. 
     FIG. 9F shows a graphic representation of a passive acoustic radiator illustrated as a series augmented passive radiator. 
     FIG. 9G shows a graphic representation of a passive acoustic radiator illustrated as a second type of parallel augmented passive radiator. 
     FIG. 10A illustrates a graphic representation of a construction of the differential area passive radiator. 
     FIG. 10B illustrates a graphic representation of a construction variation of the differential area passive radiator. 
     FIG. 10C illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 10D illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 10E illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 10F illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 10G illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 10H illustrates a graphic representation of another construction variation of the differential area passive radiator. 
     FIG. 11A depicts a graphic representation of the embodiment of FIG. 7A with one port removed. 
     FIG. 11B shows a graphic representation of a functional equivalent to FIG. 11A but of a different configuration. 
     FIG. 11C shows a graphic representation of a functional equivalent to FIG. 7A but with different passive acoustic radiators. 
     FIG. 11D shows a graphic representation of a functional equivalent to FIG. 11C but of a different configuration. 
     FIG. 12A shows graphic representation of the invention of an improved augmented passive radiator system. 
     FIG. 12B shows a graphic representation of a functional equivalent to FIG. 12A with a different configuration and passive acoustic radiator. 
     FIG. 13A shows the invention with each surface of the transducer coupled to a separate differential area passive radiator and each differential area passive radiator coupled to the other differential area passive radiator. 
     FIG. 13B shows a graphic representation of the invention with one surface of the transducer coupled to a differential area passive radiator and the other to an augmented passive radiator. 
     FIG. 13C shows a graphic representation of a functional equivalent to FIG. 13B but with different passive acoustic radiators. 
     FIG. 13D shows a graphic representation of a functional equivalent to FIG. 13B but of a different configuration. 
     FIG. 13E shows a graphic representation of a functional equivalent to FIG. 13D but with different passive acoustic radiators. 
     FIG. 13F shows a graphic representation of a functional equivalent to FIG. 13B but of a different configuration. 
     FIG. 13G shows a graphic representation of a functional equivalent to FIG. 13F but of a different configuration. 
     FIG. 14A shows a graphic representation of a parallel, two chamber open architecture embodiment of the invention. 
     FIG. 14B shows a graphic representation of a version of FIG. 14A further including a passive acoustic radiator. 
     FIG. 15A shows a graphic representation of a series, two chamber open architecture embodiment of the invention. 
     FIG. 15B shows a graphic representation of a version of FIG. 15A further including a passive acoustic radiator. 
     FIG. 16A shows a graphic representation of the invention with open architecture intercoupled chambers. 
     FIG. 16B shows a graphic representation of the invention with an alternative construction to the system in FIG.  16 A. 
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention. 
     FIG. 1 shows the type of prior art system disclosed in U.S. Pat. No. 4,076,097, granted to Clarke, using an augmented passive radiator. Enclosure  10  contains sub enclosure volumes  4  and  20  and active transducer  11 . Contained between the volumes is an augmented passive radiator  44  with two different diaphragm areas, a larger one  15  and a smaller one  19  mechanically coupled together and with active transducer  11  interacting with the difference area  18  of augmented passive radiator  44 . As can be seen, the surface area  19  of augmented passive radiator  44  is isolated in auxiliary volume  4  and therefore cannot be coupled to the diaphragm  13  of transducer  11  and cannot contribute acoustic output to the system and is limited by the stiffness of auxiliary volume  4 . 
     FIG. 2 shows the type of prior art system disclosed in U.S. Pat. No. 4,301,332, granted to Dusanek, that performs substantially the same as the one in FIG. 1 with the main difference being that transducer  11  is coupled to in series to the small diaphragm surface area  19  of augmented passive radiator  44 . Both of the systems in FIGS. 1 and 2 are full range systems and do not exhibit or teach an acoustic bandpass characteristic. Also, their use of the augmented passive radiator is implemented in a closed architecture with the third undriven, non-radiating diaphragm area ( 18  in FIG. 2) enclosed in an auxiliary volume  4  and cannot contribute to system output or be relieved of the stiffness in volume  4 . This diaphragm area  18  is also isolated from the electro-acoustic transducer. This same limitation is exhibited in the device of FIG. 3 except it is the smaller diaphragm  19  of the augmented passive radiator  44  that is isolated in the sealed stiffness auxiliary chamber  4 . 
     FIG. 3 shows the type of system disclosed in Geddes PCT WO99/18755 can be viewed as a series bandpass version of the augmented passive radiator system. Enclosure  10  contains sub enclosure volumes  4 ,  24  and  24   a  and active transducer  11 . Contained between the volumes is an augmented passive radiator  44   a  with two different diaphragm areas, a larger one  15  and a smaller one  19   a  mechanically coupled together and with active transducer  11  interacting with the small diaphragm area  19   a  of augmented passive radiator  44   a.  Relative to the present and parent patent applications, it can be seen, the surface area  18   a  of augmented passive radiator  44  is isolated in closed auxiliary volume  4   a  and therefore cannot be coupled to either side  21  or  22  of the diaphragm  13  of transducer  11  and also cannot contribute to the acoustic output the system. Also, because of the sealed off nature of the closed architecture, the chamber air stiffness requires that the volume be substantial to achieve reasonable performance. Port  25  enhances output from diaphragm side  21  of transducer  11  but does not enhance output from diaphragm areas  18  or  19   a  of augmented passive radiator  44   a.    
     FIG. 4 is essentially the system of FIG. 3 with port  25  replaced with augmented passive radiator  44  which operationally duplicates the function of augmented passive radiator  44  of FIG.  2 . It is shown here again that subchamber  4  isolates diaphragm  18  from diaphragm side  21  of transducer  11  and also isolates diaphragm  18  in a sealed off relationship from the external environment. 
     FIGS. 5A to  6 B show basic forms of the invention as disclosed in the parent patent. 
     FIG. 5A is bandpass loudspeaker enclosure system  10  incorporating primary enclosure volume  20  and primary enclosure volume  24  with a dividing wall  9  positioned between the two primary enclosure volumes. An electro-acoustic transducer  11  is mounted in an opening  7  on dividing wall  9  and includes movable diaphragm  13  which has a surface area side  21  and a surface area side  22 . Surface area side  21  of movable diaphragm  13  communicates into primary enclosure volume  20  and surface area side  22  of movable diaphragm  13  communicates into said primary enclosure volume  24 . There is a differential area passive radiator  14  that is comprised of large, primary diaphragm surface area  15  and two secondary diaphragm surface areas smaller in acoustic coupling area than primary diaphragm surface area  15 . The secondary diaphragm surface areas include a small or unitary diaphragm surface area  19  and a differential diaphragm surface area  18 . The primary diaphragm surface area  15  and the unitary diaphragm surface area  19  interconnect and include peripheral attachment means  16  and  17 . The differential diaphragm surface area  18  is defined by the differential surface area established between primary diaphragm surface area peripheral attachment means  16  and unitary diaphragm surface area peripheral attachment means  17 . 
     Unitary diaphragm surface area  19  of differential area passive radiator  14  is mounted by peripheral attachment means  17  in opening  5  between the two primary enclosure volumes  20  and  24 . Surface area side  21  of electro-acoustic transducer  11  is pneumatically coupled through the primary enclosure volume  20  to differential diaphragm surface area  18  of differential area passive radiator  14 . Surface area side  22  of electro-acoustical transducer  11  is pneumatically coupled through enclosure volume  24  to unitary diaphragm surface area  19  of differential area passive radiator  14 . 
     The primary diaphragm surface area  15  of differential area passive radiator  14  is mounted by peripheral attachment means  16  in opening  6  in primary enclosure volume  20 . The primary diaphragm surface area  15  of differential area passive radiator  14  communicates from the opening in primary enclosure volume  20  to a region outside of the two primary enclosure volumes. 
     In this embodiment, particularly when the volume of primary enclosure volume  20  is smaller than that of primary enclosure volume  24 , the active electro-acoustic transducer  11  and its diaphragm  13  form a bass reflex mode at a frequency near the upper range of the system by interacting with the differential area  18  of the differential area passive radiator  14 . At all lower frequencies active electro-acoustic transducer  11  and differential area passive radiator  14  are firmly air coupled together and operate in phase. The active transducer drives the differential area passive radiator in a parallel relationship and therefore this is considered the parallel interaction version of the invention. The volume displacement of the system is magnified by the ratio of the diaphragm area of transducer  11  and the diaphragm area of differential diaphragm  18  of differential area passive radiator  14 . If the diaphragm  13  is greater in area than differential surface area  18  then this ratio magnifies the displacement of transducer  11  to a greater displacement in differential area passive radiator  14 . The acoustic volume displacement of the system is further magnified by the ratio of the diaphragm area of transducer  11  and the diaphragm area of diaphragm  15  of differential area passive radiator  14 . 
     FIG. 5B shows another form of the invention that is considered the series interaction version of the invention. Shown is bandpass loudspeaker enclosure system  10  incorporating primary enclosure volume  20  and primary enclosure volume  24  with dividing wall  9  positioned between the two primary enclosure volumes. An electro-acoustic transducer  11  is mounted in opening  7  on dividing wall  9  and includes movable diaphragm  13  which has a surface area side  21  and a surface area side  22 . Surface area side  21  of movable diaphragm  13  communicates into primary enclosure volume  20  and surface area side  22  of movable diaphragm  13  communicates into primary enclosure volume  24 . 
     Included is differential area passive radiator  14  that is comprised of primary diaphragm surface area  15  and two secondary diaphragm surface areas smaller in acoustic coupling area than said primary diaphragm surface area  15 . The secondary diaphragm surface areas include unitary diaphragm surface area  19  and differential diaphragm surface area  18 . The primary diaphragm surface area  15  and unitary diaphragm surface area  19  interconnect and include peripheral attachment means  16  and  17 . The differential diaphragm surface area  18  is defined by the differential surface area established between primary diaphragm surface area peripheral attachment means  16  and secondary diaphragm surface area peripheral attachment means  17 . 
     The small (or unitary) diaphragm surface area  19  of the DAPR  14  is mounted by peripheral attachment means  17  in opening  5  between the two primary enclosure volumes  20  and  24 . The surface area side  21  of the electro-acoustic transducer  11  is pneumatically coupled through primary enclosure volume  20  to differential diaphragm surface area  18  of differential area passive radiator  14 . The surface area side  22  of the electro-acoustical transducer  11  is pneumatically coupled through primary enclosure volume  24  to unitary diaphragm surface area  19  of differential area passive radiator  14 . The primary diaphragm surface area  15  of differential area passive radiator  14  is mounted by peripheral attachment means  16  in opening  6  in primary enclosure volume  20 . The primary diaphragm surface area  15  of DAPR  14  communicates from the opening in primary enclosure volume  20  to a region outside of the two primary enclosure volumes. 
     In this embodiment, particularly when the volume of primary enclosure volume  24  is smaller than that of primary enclosure volume  20 , the driving force of the active electro-acoustic transducer  11  and its diaphragm  13  interact to couple with the smaller diaphragm area  19  of the differential area passive radiator  14  and therefore at low frequencies active electro-acoustic transducer  11  and differential area passive radiator  14  operate in phase. The active transducer drives the differential area passive radiator in a serial relationship and therefore this is considered the series interaction version of the invention. The output of the active transducer  11  is magnified to substantially the same extent as the device in FIG. 5A assuming that the diaphragm area of differential diaphragm area  18  in FIG. 5A is the same effective surface area as the diaphragm area of unitary diaphragm area  19  of FIG.  5 B and the diaphragm area  13  is the same in both FIGS. 5A and 5B. 
     Any embodiments of the invention that use a form of passive acoustic energy radiator may borrow from the group that is known in the industry that include but are not limited to, vent openings, extended port tubes or suspended passive diaphragms. An augmented passive radiator, DAPR, or two suspended passive diaphragms connected back to back with an auxiliary chamber, may also be used as the passive acoustic energy radiator. 
     FIG. 6A is the bandpass loudspeaker enclosure system of FIG. 5A further including a passive acoustic energy radiator  25 , expressed here as an elongated port, communicating from the interior to the outside of primary enclosure volume  24 . With this embodiment the open architecture of the differential area passive radiator  14  contributes significant increases in output. At the lowest frequencies reproduced by the system the open, shared volume  24  allows the surface area  22  of diaphragm  13  of transducer  11  to sum together with surface area  19  of differential area passive radiator  14  to deliver very high acoustic output through passive acoustic energy radiator  25 . 
     FIG. 6B is the bandpass loudspeaker enclosure system of FIG. 5B further including a passive acoustic energy radiator  25 , expressed here as an elongated port, communicating from the interior to the exterior of primary enclosure volume  20 . With this embodiment the open architecture of the differential area passive radiator  14  contributes significant increases in output. At the lowest frequencies reproduced by the system the open, shared volume  20  allows the surface area  21  of diaphragm  13  of transducer  11  to sum together with differential diaphragm surface area  18  of differential area passive radiator  14  to deliver very high acoustic output through passive acoustic energy radiator  25 . 
     An example of the parameters for a system of FIG. 6B reduced to practice is as follows: Specifications for a system as shown in FIG. 6B 
     
       
         
           
               
             
               
                   
               
               
                 Electro-acoustic transducer 11 parameters 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 Diaphragm 13 diameter: 
                 6.5″ 
               
               
                 Free air resonance: 
                 45 Hz 
               
               
                 Moving mass: 
                 0.03 kg 
               
               
                 DC resistance: 
                 6.2 ohms 
               
               
                 Qes: 
                 .27 
               
               
                 Qms: 
                 6.5 
               
               
                 Passive elements 
               
               
                 Differential Area Passive Radiator unitary diaphragm 
                 6.5″ 
               
               
                 diameter 19: 
               
               
                 Differential Area Passive Radiator Primary diaphragm 
                 8.0″ 
               
               
                 diameter: 
               
               
                 Primary Enclosure Volume 20: 
                 2670 cubic inches 
               
               
                 Primary Enclosure Volume 24: 
                 130 cubic inches 
               
               
                 Diameter of port 25: 
                 4″ 
               
               
                 Length of port 25: 
                 15″ 
               
               
                 Differential Area Passive Radiator 14 mass: 
                 0.070 Kg 
               
               
                 Differential Area Passive Radiator 14 free air 
                 40 Hz 
               
               
                 resonance: 
               
               
                   
               
            
           
         
       
     
     These general parameters can be applied as a starting point for all the various inventive embodiments disclosed. 
     FIGS. 7A,  7 B,  8   a  and  8   b  show more forms of the invention expressed in the parent cases. 
     FIG. 7A shows a bandpass loudspeaker enclosure system  10  incorporating primary enclosure volume  20 , primary enclosure volume  24  and primary enclosure volume  90 . A dividing wall  9  is positioned between primary enclosure volumes  20  and  24  and in this embodiment divides chambers or primary enclosure volumes  20  and  90 . Dividing wall  9   a  isolates chamber  90  from chamber or primary enclosure volume  24 . An electro-acoustic transducer  11  is mounted on dividing wall  9  and includes movable diaphragm  13  having a surface area side  21  and a surface area side  22 . The surface area side  21  of movable diaphragm communicates into primary enclosure volume  20  and surface area side  22  of the movable diaphragm  13  communicates into primary enclosure volume  24 . A differential area passive radiator  14  includes primary diaphragm surface area  15  and two secondary diaphragm surface areas, both smaller in acoustic coupling area than the primary diaphragm surface area  15 . The secondary diaphragm surface areas include a unitary diaphragm surface area  19  and a differential diaphragm surface area  18 . The primary diaphragm surface area  15  and unitary diaphragm surface area  19  are interconnected and include peripheral attachment means  16  and  17 . 
     The differential diaphragm surface area  18  is defined by the differential surface area established between the primary diaphragm surface area peripheral attachment means  16  and unitary diaphragm surface area peripheral attachment means  17 . The surface area  21  of the electro-acoustic transducer  11  is pneumatically coupled through primary enclosure volume  20  to differential diaphragm surface area  18  of differential area passive radiator  14 . The surface area side  22  of the electro-acoustical transducer  11  is pneumatically coupled through primary enclosure volume  24  to passive acoustic energy radiator  95  which communicates from the interior to the exterior of primary enclosure volume  24 . The passive acoustic radiator  95  is shown here as a port. Unitary diaphragm surface area  19  of differential area passive radiator  14  is pneumatically coupled through primary enclosure volume  90  to passive acoustic energy radiator  96  which communicates from the interior to the exterior of primary enclosure volume  90 . Passive acoustic radiator  96  is shown here as a port. The primary diaphragm surface area  15  of differential area passive radiator  14  communicates to a region outside of primary enclosure volumes  20 ,  24  and  90 . 
     Another, simplified, description of FIG. 7A is that of a bandpass loudspeaker enclosure system  10  with a transducer  11  operating in a parallel relationship to a differential area passive radiator. The bandpass loudspeaker system  10  includes: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  with three separate acoustical coupling surface areas, the largest, primary acoustical coupling surface area  15 , the differential area acoustical coupling surface area  18 , and the small unitary acoustical coupling surface area  19 ; 
     c) the first acoustical coupling surface  21  of the said vibratable diaphragm  13  substantially air coupled through a first enclosure volume  20  to a first of the three separate acoustical coupling surface areas, here in the parallel case, differential surface area  18  of said at least one differential area passive radiator  14 ; 
     d) a second of the three separate acoustical coupling surface areas, small unitary surface area  19  of said at least one differential area passive radiator  14  being substantially air coupled through a second chamber  90  to the external environment through an acoustic opening of predetermined dimensions or passive acoustic radiator of predetermined characteristics  96 . Opening  96  is shown here as an elongated port but can be of any passive acoustic radiator construction known in the art including those in FIGS. 9A to  9 G; and 
     e) a third and largest of the three separate acoustical coupling surface areas, large primary acoustical coupling area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) said second acoustical coupling surface of the said vibratable diaphragm substantially air coupled into a third enclosure volume  24 . Passive acoustic radiator  95 , shown here as an elongated port couples the output of side  22  of diaphragm  13  to the external environment. Passive acoustic radiator  95  can be of any passive acoustic radiator construction known in the art including those in FIGS. 9 a  to  9   g.    
     In this  7 A embodiment the inventive structure uses the active electroacoustic transducer  11  to drive the differential surface area diaphragm  18  throughout the passband of the system with the ratio of the area of differential diaphragm area  18  to the area of the large or primary diaphragm area  15  being a step up ratio of the system causing an acoustical transformation of the acoustical output of electroacoustical transducer  11 . A further acoustic transformation is caused by the diaphragm area ratio of the acoustic surface area transducer diaphragm  13  to acoustic diaphragm surface area of differential surface area  18  of differential area passive radiator  14 . The transducer is also coupled into chamber  24  which is tuned to a bass reflex resonant frequency determined by the compliance of chamber  24  resonating with the acoustic mass of passive acoustic radiator  95 . This can reduce the required diaphragm displacement of transducer  11  while increasing acoustic output of the system at this reflex tuning frequency. 
     The small or unitary diaphragm surface area  19  of differential area passive radiator  14  is coupled into chamber  90  and which has a bass reflex resonant frequency determined by the acoustic compliance of chamber  90  resonating with the acoustic mass of passive acoustic radiator  96 . If tuned to a frequency at or below the bandpass of the system, this open architecture approach can reduce diaphragm displacement of both the electroacoustic transducer  11  and differential area passive radiator  14  while increasing total system acoustic output at the reflex tuning frequency. Another approach to using the open architecture of chamber  90  through passive acoustic radiator  96  is to tune the mass and compliance of radiator  96  and chamber  90  to a higher frequency either in the upper end of the system passband or the above the passband, in the upper stop band of the system. By doing this the size of chamber  90  may be substantially reduced with a small impact on system performance. Opening  96  may also be constructed to have the predetermined characteristic of increased acoustic resistance. This increased acoustic resistance can damp the reflex tuning to minimize any aberrations in the upper band frequency response and contribute to minimizing acoustic cancellation of the output from diaphragm surface area  19  and diaphragm surface area  15 . A version of FIG. 7A with acoustic resistance in passive acoustic radiator  96  is schematically illustrated with passive acoustic radiator  96   a  in FIG.  11 C. 
     The parallel structure of FIG. 7A may be preferred when the differential area passive radiator ratio is less than two to one due to lower DAPR mass for all ratios less than two to one. When the differential area passive radiator ratio is greater than two to one then the series version of FIG. 7A, shown in FIG. 7B may be preferred due to lower DAPR mass for all ratios greater than two to one. 
     FIG. 7B shows an equivalent but alternative version of the embodiment of FIG. 7A with transducer  11  operating in a series relationship with differential area passive radiator  14 . Shown is bandpass loudspeaker system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  with three separate acoustical coupling surface areas, the largest, large primary acoustical coupling surface area  15 , the differential area acoustical coupling surface area  18 , and the small unitary acoustical coupling surface area  19 ; 
     c) the first acoustical coupling surface  21  of the said vibratable diaphragm  13  being substantially air coupled through a first enclosure volume  90  to a first of the three separate acoustical coupling surface areas, small unitary surface area  19  of said at least one differential area passive radiator  14 ; 
     d) a second of the three separate acoustical coupling surface areas, differential surface area  18  of said at least one differential area passive radiator  14  is substantially air coupled through a second chamber  20  to the external environment through an acoustic opening of predetermined dimensions or passive acoustic radiator of predetermined characteristics  96 . Passive acoustic radiator  96  is shown here as an elongated port but can be of any passive acoustic radiator construction known in the art including those in FIGS. 9 a  to  9   g;  and 
     e) a third and largest of the three separate acoustical coupling surface areas, primary surface area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) said second acoustical coupling surface  22  of the said vibratable diaphragm being substantially air coupled into a third enclosure volume  24 . Restricted acoustic opening or passive acoustic radiator  95 , shown here as an elongated port, couples the output of side  22  of diaphragm  13  to the external environment. Passive acoustic radiator  95  can be of any passive acoustic radiator construction known in the art including those in FIGS. 9 a  to  9   g.    
     All of the attributes of this embodiment are essentially the same as that of FIG. 7A except for the preference of this series configuration being preferable in systems using greater than two to one DAPR transformation ratios. 
     Various restricted openings or portals are known in the art of loudspeakers. These acoustic openings or portals for this invention are of predetermined dimensions and are at least partially acoustically transparent relating to frequency and/or attenuation depending on their characteristics of acoustic mass, acoustic resistance and in some cases compliance. They are generally known as passive acoustic radiators and have been well developed in various forms. 
     As disclosed in FIG. 9 of parent application No.-553, FIG. 8 a  shows a speaker configuration  10  having a resistive opening  41  that may exist from a subchamber  21  as when the subchamber is not perfectly sealed. This resistive opening is generally understood by those skilled in the art to be a passive acoustic radiator with a predetermined characteristic of acoustic resistance. In some system alignments, the resistive leakage may be used to achieve resistive damping to the diaphragm enclosed in the subchamber. This is particularly useful if a transducer is used that exhibits an underdamped characteristic or has output that is desired to be attenuated but not totally sealed off from an external environment. 
     In any of the disclosed systems a subchamber may have a predetermined leakage to the region outside the enclosure with the leakage characterized as an acoustic resistance. This approach can be optimized by use of a predetermined acoustic resistance. 
     As disclosed in FIG. 6 of parent application No.-553, FIG. 8 b  shows a speaker configuration  10  having a flared port  31  exiting from chamber  23  of enclosure  10 . A second flared port  30  is used to intercouple chambers  22  and  23 . Flared ports of this type can be used where ever a passive acoustic radiator is specified and can offer the advantages of lower resistive losses, reduced air turbulence and noise. 
     Various restricted openings or portals are known in the art of loudspeakers. In this invention it would be important to have any of these openings be of predetermined dimensions. These acoustic openings or portals are at least partially acoustically transparent relating to frequency and/or attenuation depending on their characteristics of acoustic mass, acoustic resistance and in some cases compliance. They are generally known as passive acoustic radiators and have been well developed in various forms. Some of the most commonly know are illustrated in FIGS. 9A to  9 G. 
     FIG. 9A shows an opening  111  through a wall or partition  110  that represents prior art passive acoustic radiator commonly referred to as a vent. This would be considered an opening of predetermined dimensions with a characteristic acoustic mass. FIG. 9B shows an elongated pipe  112  mounted through a wall or partition  110  that represents prior art passive acoustic radiator commonly referred to as a port. The terms port and vent are generally used interchangeably in the art. 
     FIG. 9C illustrates an acoustically lossy version of a vent or port opening. As it is known in the art all ports and vents have the characteristic of acoustic mass and acoustic resistance. Acoustic mass is increased by reducing the diameter of a vent/port and/or increasing the length of the vent/port. As it is commonly known in the art, acoustic resistance is increased by introducing an acoustically lossy medium  114  in the opening  111  in partition  110  by reducing the diameter of the vent/port, having an increased number of small diameter vent/ports or to restrict the airflow through a vent/port opening with an acoustically resistive material such as felt, cellular foam, fiberglass or other materials known in the art for acoustic resistance. FIG. 9D shows another embodiment of an elongated pipe  12  having a low loss port opening  111  in partition  110  with flared openings  115   a  and  115   b.  As it is known in the art flared openings can be used to create a lower loss, lower noise port by minimizing ingress and egress turbulence. 
     FIG. 9E shows an opening  115  in a wall or partition  110  that has a passive suspended radiator  113  mounted in the opening  115  suspended by surround/suspension  116  and represents prior art passive acoustic radiator called a passive radiator or passive suspended radiator. In addition to the characteristics of acoustic mass and acoustic resistance that are embodied in other passive acoustic radiators, this passive acoustic radiator also includes the characteristic of compliance. 
     FIG. 9F shows an auxiliary enclosure volume  4  with a differential area passive radiator  14  mounted in an opening  118  in the auxiliary enclosure volume. This represents a series augmented passive radiator wherein a small or unitary diaphragm surface area  19  would be acoustically coupled to the output from an electroacoustic transducer (not shown). See prior art FIG.  2 . The large or primary diaphragm surface area  15  is usually coupled to the external environment and the differential diaphragm surface area  18  is coupled into and isolated in an auxiliary subchamber  4 . 
     FIG. 9G shows an auxiliary enclosure volume  4  with a differential area passive radiator  14  mounted in two different openings  116  and  117  in the auxiliary enclosure volume  4 . This represents a parallel augmented passive radiator wherein the differential diaphragm surface area  18  would be acoustically coupled to the output from an electroacoustic transducer. See prior art FIG.  1 . The large or primary diaphragm surface area  15  is usually coupled to the external environment and the small or unitary diaphragm surface area  19  is coupled into and isolated in an auxiliary subchamber  4 . 
     Any of the embodiments of known passive acoustic radiators, including those shown in FIGS. 9A through 9G, may be interchanged within the embodiments disclosed herein where ever a passive acoustic radiator is specified. 
     FIG. 10A shows a construction of a differential area passive radiator  14  that is comprised of the largest, primary diaphragm surface area  15  and two secondary diaphragm surface areas  18  and  19  smaller in acoustic coupling area than primary diaphragm surface area  15 . The secondary diaphragm surface areas include a small, unitary diaphragm surface area  19  and a differential diaphragm surface area  18 . The primary diaphragm surface area  15  and the unitary diaphragm surface area  19  interconnect and each include peripheral attachment means  16  and  17 . The differential diaphragm surface area  18  is defined by the differential surface area established between the primary diaphragm surface area peripheral attachment means  16  and the unitary diaphragm surface area peripheral attachment means  17 . In most constructions, the effective acoustic area of the different diaphragm surface area  18  is usually calculated by subtracting the small unitary diaphragm surface area  19  from the large primary diaphragm surface area  15 . 
     FIG. 10B shows a construction of a differential area passive radiator  14 , where the large primary diaphragm area  15  is expressed in a flat piston form. This may be of a skinned honeycomb construction for rigidity. 
     FIG. 10C shows a construction of a differential area passive radiator  14 , where the small unitary diaphragm area  19  is expressed as a sealed off portion of the smaller open end of conical loudspeaker cone diaphragm  15 . This is particularly useful when the lowest mass construction and simplicity is a high priority. The DAPR in FIG. 10C is for use in bandpass loudspeaker where a simplified and/or low mass differential area passive radiator is needed with the system including: an enclosure volume, including at least two chambers; at least one active transducer having first and second sides of a vibratable diaphragm both contained within the enclosure volume; at least one differential area passive radiator comprised of: 
     a) a single conical diaphragm with a small diameter end and a large diameter end, 
     b) a surround suspension attached to the small diameter end of the conical diaphragm, 
     c) a surround suspension attached to the large diameter end of the conical diaphragm, 
     d) an intermediate wall structure coupled to the small diameter end of the conical diaphragm for sealing off the inside of the conical diaphragm. 
     FIG. 10D shows a version of the differential area passive radiator  14 , with the large primary diaphragm area  15  is substantially the same as FIG. 10B but with the small unitary diaphragm area  19  captured by open cylinder  120 . 
     FIG. 10E shows a version of the differential area passive radiator  14 , with the large primary diaphragm area  15  expressed as a thin film diaphragm such as polyester, polypropylene or Kapton™ film. FIG. 10F shows a version of the differential area passive radiator  14  with the small unitary diaphragm area  19  also being expressed in a flat piston form, the large primary diaphragm  15  expressed as a flat piston form and mechanical connection means  28  joining the two diaphragms together. These diaphragms may be of a skinned honeycomb construction for rigidity. 
     FIG. 10G shows a version of the differential area passive radiator  14 , with the large primary diaphragm area  15  is substantially the same as FIG. 10A but with the small diaphragm area  19  expressed as an open cylinder. 
     FIG. 10H shows a version of the differential area passive radiator  14 , similar to that in FIG. 10E with the large diaphragm area  15  using at least two thin films  121  and  122  in parallel and being forcibly separated. The separation may be facilitated by a volume of air  123  trapped inside and sealed off from the outside or by other filler material or structural means. 
     FIG. 11A shows the parallel driven differential area passive radiator embodiment disclosed in FIG. 7A except without passive acoustic radiator  95  in FIG. 7A, creating a substantially sealed sub enclosure  24  while still maintaining the inventive open architecture by venting the output of acoustic surface area  19  of differential area passive radiator  14  through passive acoustic radiator  96  shown here as an elongated port. This port may be tuned at the upper end or above the passband or alternatively it can be tuned near the lower end of the passband of the bandpass enclosure system  10 . 
     FIG. 11B is the series driven equivalent of FIG. 11A wherein active transducer  11  is coupled in series through enclosure volume  90  with acoustic surface area  19  of differential area passive radiator  14 . Differential surface area  18  of differential area passive radiator  14  is coupled through enclosure volume  20  on through passive acoustic radiator  96 , shown here as an elongated port, to the external environment. 
     FIG. 11C is the embodiment of FIG. 7A with a different set of passive acoustic radiators. Passive acoustic radiator  95   a  is a flared, low loss port as shown in FIG.  9 D. Low loss ports can give the best performance in enclosure volume  24  wherein active transducer  11  operates through this enclosure volume in the manner of a bass reflex system with a port tuning frequency near the low frequency cutoff of the bandpass enclosure system  10 . FIG. 11C further illustrates a lossy resistive vent as passive acoustic radiator  96   a.  A lossy vent is used in this location of coupling small unitary diaphragm area  19  of differential area passive radiator  14  through enclosure volume  90  to the external environment. In one approach, this resistive vent  96   a  may be tuned to a frequency at the upper end or above the passband of the bandpass enclosure system  10 . This higher frequency tuning of a lossy vent can reduce the effects of stiffness in enclosure volume  20  throughout the passband such that it can be reduced in size for a given performance compared to the sealed off chamber in prior art augmented passive radiator or acoustic lever systems. 
     An alternative description of FIG. 11C is generally described as a bandpass loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  within the enclosure system having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18  wherein at least two surfaces areas are of different sizes; 
     c) the first acoustical coupling surface  21  of the vibratable diaphragm  13  being substantially air coupled through a first enclosure volume  20  to a first of the three separate acoustical coupling surface areas, differential surface area  18  of the at least one differential area passive radiator  14 ; 
     d) a second of the three separate acoustical coupling surface areas, small unitary surface area  19  of the at least one differential area passive radiator  14  is substantially air coupled through a second chamber  90  to the external environment through a restricted opening or passive acoustic radiator  96   a  of predetermined characteristics; and 
     e) a third and largest of the three separate acoustical coupling surface areas, primary surface area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) the second acoustical coupling surface  22  of the said vibratable diaphragm being substantially air coupled into a third enclosure volume and ported to the external environment through passive acoustic radiator  95   a,  expressed here as a flared, low loss elongated port. 
     FIG. 11D is a parallel version of the embodiment in FIG. 11C with the differential area passive radiator  14  now being driven from active transducer  11  by coupling in series with diaphragm surface area  19  of differential area passive radiator  14 . Differential surface area  18  in this series version is coupled through enclosure volume  20  to the external environment through passive acoustic radiator  96   a,  shown here as a resistive vent. 
     The embodiments of FIGS. 11D and 11C may operate with the passive acoustic radiators  95  and  95   a  eliminated as in FIGS. 11A and B. 
     The differential area passive radiator system is considered to be driven in the parallel mode when the primary coupling between the active transducer  11  and differential area passive radiator  14  is through the small, unitary surface area  19 . It is considered to be driven in the parallel mode when the primary coupling from the active transducer  11  is to differential surface area  18  of the differential area passive radiator  14  (or differential area passive radiator  44  in the case of FIGS. 12A and B.) 
     It has been discovered by the inventor that the parallel mode can offer superior performance due to lower moving mass with available diaphragms when the system ratio through the differential area passive radiator is two to one or less. Relating this to FIG. 11A, a bandpass loudspeaker  10  including at least one differential area passive radiator  14  and at least one active transducer  11  with a vibratable diaphragm  13 . The at least one differential area passive radiator  14  includes a small surface area  19 , a differential surface area  18  and a large surface area  15 . The differential area passive radiator  14  is operated with an acoustic transforming ratio of equal to or less than two to one, meaning that the ratio of the large surface area  15  to the smaller surface area that the diaphragm  13  is coupled to (in this case  18 ), is equal to or less than two to one. The at least one transducer  11  with said vibratable diaphragm  13  acoustically is coupled through an isolated enclosure volume  20  to the differential surface area  18  of said at least one differential area passive radiator. 
     FIG. 12A shows an enhanced, parallel DAPR system utilizing the open architecture of the invention. Enclosure  10  contains sub enclosure volumes  4  and  20  and active transducer  11 . Contained between the volumes is a DAPR  44  with three different diaphragm areas, a large primary surface area  15  and a smaller unitary surface area  19  mechanically coupled together and with active transducer  11  interacting with the differential surface area  18  of DAPR  44 . As can be seen, the surface area  19  of DAPR  44  is no longer completely sealed into and confined to sealed auxiliary volume  4  due to passive acoustic radiator  120  shown in this embodiment as a lossy vent opening. This lossy vent opening can be tuned to a higher frequency than the resonant frequency of the DAPR and can allow the reduction in size of auxiliary volume  4  while maintaining substantially the same system performance. 
     Alternatively FIG. 12A can be described as, a loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  44  within the enclosure system having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18  wherein at least two surfaces areas are of different sizes; 
     c) the first acoustical coupling surface area  21  of the said vibratable diaphragm is substantially air coupled through a first enclosure volume  20  to a first of the three separate acoustical coupling surface areas, differential surface area  18  of the differential area passive radiator  44 ; 
     d) a second of the three separate acoustical coupling surface areas, the small unitary surface area  19  of the at least one differential area passive radiator  44  is acoustically coupled through a second chamber  4  to the external environment through a restricted opening or passive acoustic radiator  120 , shown here as a resistive vent of predetermined characteristics; and 
     e) a third and largest, primary surface area  15  of the three separate acoustical coupling surface areas of the at least one differential area passive radiator  44  is acoustically coupled to the external environment. 
     When using the passive acoustic radiator or resistive vent tuned to a frequency above that of the resonant frequency or passband of the DAPR it can further improve the performance of the system if the passive acoustic radiator is placed on the far side of the enclosure opposite the differential area passive radiator as illustrated in FIG.  12 A. 
     FIG. 12B shows an enhanced, series DAPR system that performs substantially the same as the one in FIG. 12A with the main difference being that transducer  11  is coupled in series to the small diaphragm area  19  of DAPR  44 . Here passive acoustic radiator  120   a,  shown here as an elongated port, vents the acoustical energy from diaphragm area  19  of passive radiator  44  to the external environment. In one version of this embodiment this passive acoustic radiator can be tuned below or above the resonant frequency or passband of the DAPR to further augment output and reduce diaphragm displacement in the passband or to relieve stiffness of auxiliary chamber  4  and therefore allow its volume to be reduced. 
     Alternatively FIG. 12B can be described as, a loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  44  within the enclosure system having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18  wherein at least two surfaces areas are of different sizes; 
     c) the first acoustical coupling surface area  21  of the said vibratable diaphragm is substantially air coupled through a first enclosure volume  24  to a first of the three separate acoustical coupling surface areas  19  of the differential area passive radiator  44 ; 
     d) a second of the three separate acoustical coupling surface areas  18  of the at least one differential area passive radiator  44  is acoustically coupled through a second chamber  4  to the external environment through a restricted opening or passive acoustic radiator  120   a,  shown here as an elongated port of predetermined characteristics; and 
     e) a third and largest primary surface area  15  of the three separate acoustical coupling surface areas of the at least one differential area passive radiator  44  is acoustically coupled to the external environment. 
     Both FIGS. 12A and 12B can substitute any of the passive acoustic radiators in FIGS. 9A to  9 G for the illustrated passive acoustic radiators  120  and  121 . 
     Also, both FIGS. 12A and 12B can be considered closed architecture, augmented passive radiator systems that have been significantly improved by converting them to an open architecture, differential area passive radiator system by opening up auxiliary chamber  4  with a passive acoustic radiator. 
     FIG. 13A shows a bandpass loudspeaker enclosure system  10  incorporating primary enclosure volume  20 , primary enclosure volume  24 , and primary enclosure volume  80 . Dividing wall  9  is positioned between primary enclosure volumes  20  and  24 . Electro-acoustic transducer  11  is mounted on dividing wall  9  and includes movable diaphragm  13  which has surface area side  21  and a surface area side  22 . The surface area side  21  of movable diaphragm  13  communicates into primary enclosure volume  20  and surface area side  22  of movable diaphragm  13  communicates into primary enclosure volume  24 . There are first and second differential area passive radiators  14  and  84  which include large primary diaphragm surface areas  15  and  85  and two secondary diaphragm surface areas smaller in acoustic coupling area than the primary diaphragm surface areas. The secondary diaphragm surface areas include small unitary diaphragm surface areas  19  and  89  and differential diaphragm surface areas  18  and  88 . The primary diaphragm surface areas  15  and  85  are interconnected to unitary diaphragm surface areas  19  and  89  and include peripheral attachment means  16 ,  17 ,  86 , and  87 . 
     The differential diaphragm surface area  18  is defined by the differential surface area established between primary diaphragm surface area  15  peripheral attachment means  16  and secondary diaphragm surface area peripheral attachment means  17 . The differential diaphragm surface area  88  is defined by the differential surface area established between primary diaphragm surface area  85 , peripheral attachment means  86 , and secondary diaphragm surface area peripheral attachment means  87 . The surface area side  21  of electro-acoustic transducer  11  is pneumatically coupled through primary enclosure volume  20  to differential diaphragm surface area  18  of DAPR  14 . The surface area side  22  of electro-acoustical transducer  11  is pneumatically coupled through primary enclosure volume  24  to differential diaphragm surface area  88  of second DAPR  84 . The unitary diaphragm surface area  19  of differential area passive radiator  14  and the unitary diaphragm surface area  89  of differential area passive radiator  84  are pneumatically coupled to each other through primary enclosure volume  80 . The primary diaphragm surface areas  15  and  85  of first and second differential area passive radiators  14  and  84  have one surface area side communicating outside of all three primary enclosure volumes  20 ,  24 , and  80 . 
     FIG. 13B is a bandpass loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  which has a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  within the enclosure system having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18  wherein at least two surfaces areas are of different sizes; 
     c) the first acoustical coupling surface  21  of the vibratable diaphragm  13  being substantially air coupled through a first enclosure volume  20  to a first  18  of the three separate acoustical coupling surface areas of said at least one differential area passive radiator  14 ; 
     d) a second, small unitary surface area  19  of the three separate acoustical coupling surface areas of the at least one DAPR  14  is acoustically coupled into a second chamber  80   b  and from the second chamber to the external environment through at least a first passive acoustic radiator  96  of predetermined acoustical characteristics; and 
     e) a third and largest of the three separate acoustical coupling surface areas, primary surface area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) said second acoustical coupling surface  22  of the said vibratable diaphragm  13  substantially air coupled into a third enclosure volume  24 . The at least a first passive acoustic radiator  96  has a predetermined characteristic of acoustic mass. The third enclosure volume  24  is coupled to an augmented passive radiator  84  differential surface area  88  with one surface area  89  coupled to a fourth enclosure volume  80   a.  Second surface area  88  of augmented passive radiator  84  is coupled to vibratable diaphragm surface side  22 . Large diaphragm surface area  85  of the augmented passive radiator  84  is coupled to the external environment. The small diaphragm surface area  89  of differential area passive radiator  84  is coupled through enclosure volume  80   a  to the external environment through passive acoustic radiator  195 . Passive acoustic radiator  96  can be tuned above the passband of the bandpass system  10  allowing reduction of the size of chamber  80   b.  Passive acoustic radiator  195  can be tuned above the passband of the bandpass system  10  allowing reduction of the size of chamber  80   a.  Both passive acoustic radiators may also be tuned in or near the lower end of the passband to increase the acoustic output of the system. There may also be a mixture of tuning one higher and the other lower with the passive acoustic radiator  96  usually being tuned to the higher of the two frequencies. 
     If chamber  80   a  were to remain sealed without passive acoustic radiator  195 , then  84  would operate as a closed architecture augmented passive radiator. By opening the chamber  80   a  to the external environment with passive acoustic radiator  195  this portion of the system is “converted” to an open architecture differential area passive radiator. 
     FIG. 13C is essentially the same configuration as that of FIG. 13B with the exception of passive acoustic radiators  195   a  and  96   a  both being shown as lossy vents with a predetermined dominant characteristic of acoustic resistivity. The passive acoustic radiators of FIGS. 13B and C may be mixed and matched differently or any known passive acoustic radiator including those from FIGS. 9A to  9 G may be utilized. Also, passive acoustic radiators  195  and  195   a  can be omitted as in FIG.  13 A. 
     If chamber  80   a  were to remain sealed without passive acoustic radiator  195   a  then  84  would operate as a closed architecture augmented passive radiator. By opening the chamber  80   a  to the external environment with passive acoustic radiator  195   a,  including an acoustically resistive characteristic, this portion of the system is “converted” to an open architecture differential area passive radiator. 
     FIG. 13D is a series version of FIG. 13B illustrating a bandpass loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  within the enclosure system having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18  wherein at least two surfaces areas are of different sizes; 
     c) the first acoustical coupling surface  21  of the vibratable diaphragm  13  being substantially air coupled through a first enclosure volume  20  to a first, smaller unitary surface area  19  of the three separate acoustical coupling surface areas of said at least one differential area passive radiator  14 ; 
     d) a second  18  of the three separate acoustical coupling surface areas of the at least one differential area passive radiator  14  acoustically coupled into a second chamber  80   b  and from the second chamber to the external environment through at least a first passive acoustic radiator  96  of predetermined characteristics; and 
     e) a third and largest of the three separate acoustical coupling surface areas  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) said second acoustical coupling surface  22  of the said vibratable diaphragm  13  being substantially air coupled into a third enclosure volume  24 . The at least a first passive acoustic radiator  96  has a predetermined characteristic of acoustic mass. The third enclosure volume  24  is coupled to an DAPR  84  a first small unitary surface area  89  with one surface area  88  coupled to a fourth enclosure volume  80   a.  Second surface area, small unitary surface area  89  of DAPR  84  is coupled to vibratable diaphragm surface side  22 . Large diaphragm surface area  85  of the DAPR  84  is coupled to the external environment. The small unitary diaphragm surface area  89  of differential area passive radiator  84  is coupled through enclosure volume  80   a  to the external environment through passive acoustic radiator  195 . In one preferred embodiment passive acoustic radiator  96  can be tuned above the passband of the bandpass system  10 . In one preferred embodiment passive acoustic radiator  195  can be tuned above the passband of the bandpass system  10 . 
     If chamber  80   a  were to remain sealed without passive acoustic radiator  195 , then  84  would operate as a closed architecture augmented passive radiator. By opening the chamber  80   a  to the external environment with passive acoustic radiator  195  this portion of the system is “converted” to an open architecture differential area passive radiator. 
     FIG. 13E is essentially the same configuration as that of FIG. 13D with the exception of passive acoustic radiators  195   a  and  96   a  both being lossy vents with a dominant acoustically resistive characteristic. The passive acoustic radiators of FIGS. 13D and E may be mixed and matched differently or any passive acoustic radiator may be utilized including those from FIGS. 9A to  9 G. Also, passive acoustic radiator  195   a  can be omitted while the invented system will maintain superior performance to that of the fully closed architecture prior art systems. 
     If chamber  80   a  were to remain sealed without passive acoustic radiator  195 , then back to back passive cone structure  84  would operate as a closed architecture augmented passive radiator. By opening the chamber  80   a  to the external environment with passive acoustic radiator  195   a,  this portion of the system is “converted” to an open architecture differential area passive radiator. 
     FIGS. 13F and G are a mixture of the attributes of  13 B, C, D, and E.  13 F is a parallel/series hybrid with transducer  11  driving differential diaphragm  18  of differential area passive radiator  14  in parallel mode with transducer  11  driving small unitary diaphragm surface  89  of augmented passive radiator  84  in series mode. Item  89  operating as an augmented passive radiator due to the closed architecture of auxiliary chamber  80   a.  Another way to view FIG. 13F is that of being equivalent of FIG. 11C except for the substitution of an augmented passive radiator  84  as a substitute passive acoustic radiator for passive acoustic radiator  95   a  in FIG.  11 C. The augmented passive radiator includes the fourth chamber  80   a  as its auxiliary sealed chamber. 
     FIG. 13G is and equivalent system but just the inverse of FIG. 13F with transducer  11  driving small unitary diaphragm surface  19  of open architecture, differential area passive radiator  14  in series mode and transducer  11  driving differential diaphragm surface  88  of closed architecture augmented passive radiator  84  in parallel mode. 
     FIG. 14A is another embodiment of the open architecture bandpass invention which consists of a bandpass loudspeaker enclosure system  10  including: 
     a) a total of two chambers  20  and  24  within the enclosure system; 
     b) at least one electro-acoustic transducer  11  within the enclosure system  10  having a vibratable diaphragm  13  with a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     c) at least one differential area passive radiator  14  within the enclosure system  10  having three separate acoustical coupling surface areas including: 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18 ; 
     d) a first acoustical coupling surface  21  of the said vibratable diaphragm  13  being substantially air coupled through the first chamber  20  to a first of the three separate acoustical coupling surface areas, the differential acoustical coupling surface  18 , of said at least one differential area passive radiator  14 , and 
     e) a second of the three separate acoustical coupling surface areas, the small unitary acoustical coupling surface area  19  of said at least one differential area passive radiator  14  being acoustically coupled to the external environment, 
     f) a third and largest of the three separate acoustical coupling surface areas, the primary acoustical coupling surface area  15 , of said at least one differential area passive radiator  14  acoustically coupled to the external environment, 
     g) said second acoustical coupling surface  22  of the said vibratable diaphragm  13  being substantially air coupled into the second chamber  24 . 
     In this parallel embodiment of the bandpass loudspeaker enclosure  10  system of FIG. 14A the first of three separate acoustical coupling surface areas of the differential area passive radiator  14 , which is the one acoustically coupled to the transducer diaphragm  13 , is the differential acoustical coupling surface area  18 . 
     FIG. 14B is essentially the same as that of FIG. 14A with the further addition of passive acoustic radiator  95  exiting chamber  24  to the external environment. 
     FIG. 15A is the series equivalent of the parallel version of the bandpass loudspeaker enclosure system in FIG. 14A with entails a bandpass loudspeaker enclosure system  10  including: 
     a) a total of two chambers  90  and  24  within the enclosure system; 
     b) at least one electro-acoustic transducer  11  within the enclosure system  10  having a vibratable diaphragm  13  with a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     c) at least one differential area passive radiator  14  within the enclosure system  10  having three separate acoustical coupling surface areas including 
     a small unitary acoustical coupling surface area  19 , 
     a large primary acoustical coupling surface area  15 , and 
     a differential acoustical coupling surface area  18 ; 
     d) a first acoustical coupling surface  21  of the said vibratable diaphragm  13  being substantially air coupled through the first chamber  90  to a first of the three separate acoustical coupling surface areas, the small unitary acoustical coupling surface  19 , of said at least one differential area passive radiator  14 , and 
     e) a second of the three separate acoustical coupling surface areas, the differential acoustical coupling surface area  18  of said at least one differential area passive radiator  14  being acoustically coupled to the external environment, 
     f) a third and largest of the three separate acoustical coupling surface areas, the primary acoustical coupling surface area  15 , of said at least one differential area passive radiator  14  acoustically coupled to the external environment, 
     g) said second acoustical coupling surface  22  of the said vibratable diaphragm  13  being substantially air coupled into the second chamber  24 . 
     In this series embodiment of the bandpass loudspeaker enclosure  10  system of FIG. 15A the first of three separate acoustical coupling surface areas of the differential area passive radiator  14 , which is the one acoustically coupled to the transducer diaphragm  13 , is the small unitary acoustical coupling surface area  18 . 
     FIG. 15B is essentially the same as that of FIG. 14A with the further addition of passive acoustic radiator  95  exiting chamber  24  to the external environment. 
     FIG. 16A is that of a bandpass loudspeaker enclosure system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  with three separate acoustical coupling surface areas, the largest, large primary acoustical coupling surface area  15 , the differential area acoustical coupling surface area  18 , and the small unitary acoustical coupling surface area  19 ; 
     c) the first acoustical coupling surface  21  of the said vibratable diaphragm  13  substantially air coupled through a first enclosure volume  20  to a first of the three separate acoustical coupling surface areas, here in the parallel case, differential surface area  18  of said at least one differential area passive radiator  14 ; 
     d) illustrating the novel open architecture aspect of this embodiment, a second of the three separate acoustical coupling surface areas, small unitary surface area  19  of said at least one differential area passive radiator  14  being substantially air coupled through a second chamber  90  to third chamber  24  through an acoustic opening of predetermined dimensions or passive acoustic radiator  95   b  of predetermined characteristics. Opening  95   b  is shown here as an elongated port but can be of any passive acoustic radiator construction known in the art including those in FIGS. 9A to  9 G; and 
     e) a third and largest of the three separate acoustical coupling surface areas, large primary acoustical coupling area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) again, illustrating the novel open architecture aspect of this embodiment, said second acoustical coupling surface of the said vibratable diaphragm substantially air coupled into a third enclosure volume  24  and acoustically intercoupled through passive acoustic radiator  95   b  into chamber  90 . 
     When operated in the parallel mode, structure of FIG. 16A may be preferred when the differential area passive radiator ratio is less than two to one due to lower DAPR mass for all ratios less than two to one. When the differential area passive radiator ratio is greater than two to one then the series version of FIG. 16A, shown in FIG. 16B may be preferred due to lower DAPR mass for all ratios greater than two to one. 
     FIG. 16B shows an equivalent but alternative version of the embodiment of FIG.  16 A. Shown is bandpass loudspeaker system  10  including: 
     a) at least one electro-acoustic transducer  11  with a vibratable diaphragm  13  having a first acoustical coupling surface  21  and a second acoustical coupling surface  22 ; 
     b) at least one differential area passive radiator  14  with three separate acoustical coupling surface areas, the largest, large primary acoustical coupling surface area  15 , the differential area acoustical coupling surface area  18 , and the small unitary acoustical coupling surface area  19 ; 
     c) the first acoustical coupling surface  21  of the said vibratable diaphragm  13  being substantially air coupled through a first enclosure volume  90  to a first of the three separate acoustical coupling surface areas, small unitary surface area  19  of said at least one differential area passive radiator  14 ; 
     d) a second of the three separate acoustical coupling surface areas, differential surface area  18  of said at least one differential area passive radiator  14  is substantially air coupled through a second chamber  20  to a third chamber  24  through an acoustic opening of predetermined dimensions or passive acoustic radiator of predetermined characteristics  96   b.  Passive acoustic radiator  96   b  is shown here as an elongated port but can be of any passive acoustic radiator construction known in the art including those in FIGS. 9 a  to  9   g;  and 
     e) a third and largest of the three separate acoustical coupling surface areas, primary surface area  15  of said at least one differential area passive radiator  14  acoustically coupled to the external environment; 
     f) said second acoustical coupling surface  22  of the said vibratable diaphragm being substantially air coupled into a third chamber  24  and acoustically intercoupled through passive acoustic radiator  96   b  into chamber  20 . Restricted acoustic opening or passive acoustic radiator  95 , shown here as an elongated port, couples the output of side  22  of diaphragm  13  to the external environment. Passive acoustic radiator  95  can be of any passive acoustic radiator construction known in the art including those in FIGS. 9 a  to  9   g.    
     All of the attributes of this embodiment are essentially the same as that of FIG. 16A except for the preference of when this configuration is operated in a series mode being preferable in systems using greater than two to one DAPR transformation ratios. 
     Many further variations will be obvious to one skilled in the art such as the type of diaphragm structures that can be used in all areas of diaphragm use. For example the diaphragms can be composed of a thin film, loudspeaker cones, a flat panel or other diaphragms used in the loudspeaker art. These may also be mixed between any of the diaphragm types and forms. Any of the chambers in the enclosure systems may or may not have acoustic absorption material placed inside them. Active transducers used in the systems described can be used in many orientations to achieve the equivalent result. Ratios of diaphragms, volumes and tunings can cover a broad range to achieve the desired result with the invention. Many prior art systems can be incorporated into the invention to create hybrids from systems known in the art such as Isobarik types, push-pull, negative spring systems and others known to one skilled in the art. Many substitutions for the passive acoustic energy radiator are known in the art such as various versions of vents or ports, that can be either straight or flared, and also various versions of what are known as passive radiators, drone cones or auxiliary bass radiators. As is shown there are also many variations of constructions that can realize the performance of the component specified in the invention as the A differential area passive radiator. These can be standard loudspeaker cones, or any object with a surface area that can be pneumatically driven in the manner taught by the invention. It should also be obvious to the skilled in the are that the main enclosure  10  can take what ever form required to establish the bounding surfaces of the specified sub enclosures and chambers. 
     It is evident that those skilled in the art may now make numerous other modification of and departures from the specific apparatus and techniques herein disclosed without departing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques herein disclosed and limited solely by the spirit and scope of the appended claims. 
     It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been shown in the drawings and filly described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiment(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made, without departing from the principles and concepts of the invention as set forth in the claims.