referring to fig1 ˜ 5 , a combination speaker enclosure mounting structure is shown comprised of two spherical enclosures 1 each formed of a meshed member 11 , a face panel 12 , and a back shell 13 , and a fastener 2 joining the spherical enclosures 1 . each spherical enclosure 1 has two crossed openings 14 and 15 formed in the face panel 12 and the back shell 13 at two opposite sides , for example , the top and bottom sides , two receptacles 16 and 17 respectively disposed on the inside corresponding to the crossed openings 14 and 15 , a tapered surface portion 141 corresponding to one crossed opening 14 , and a plurality of vertical stop rods 18 respectively suspended inside the crossed openings 14 and 15 . the fastener 2 is comprised of a first locating plate 21 , which comprises a plurality of locating pegs 211 radially protruded from the periphery and a plurality of axially extended screw holes 212 , a second locating plate 22 , which comprises a plurality of locating pegs 221 radially protruded from the periphery and an axially extended center screw hole 222 , a ball socket 24 , which comprises an axially extended center through hole 252 , an annular top flange 25 extended around the center through hole 252 , and a plurality of mounting holes 251 equiangularly spaced in the annular top flange 25 , a ball 23 received in the center through hole 252 of the ball socket 24 between the first locating plate 21 and the second locating plate 22 , a washer 26 supported between the second locating plate 22 and the ball socket 24 , a fixed stem 231 perpendicularly extended from the periphery of the ball 23 and inserted through the center through hole 261 of the washer 26 , a tie screw 27 threaded into the center screw hole 222 of the second locating plate 22 and a bottom screw hole ( not shown ) of the stem 231 to fix the ball 23 , the ball socket 24 , the washer 26 , and the second locating plate 22 together , a cushion 28 supported between the ball 23 and the first locating plate 21 , a spring washer 29 supported between the cushion 28 and the first locating plate 21 , and a plurality of tie screws 30 respectively threaded into the screw holes 212 of the first locating plate 21 and the mounting holes 251 of the ball socket 24 to fix the first locating plate 21 to the ball socket 24 . referring to fig6 and 7 , the first locating plate 21 and the second locating plate 22 are respectively inserted through the bottom crossed opening 15 of one spherical enclosure 1 and the top crossed opening 14 of a second spherical enclosure 1 into the corresponding receptacles 17 and 16 , and then the two spherical enclosures 1 are rotated relative to each other in reversed directions to force the locating plates 21 and 22 into friction engagement with the respective receptacles 17 and 16 . when rotating the spherical enclosures 1 relative to each other , the locating pegs 211 and 221 will be stopped at the respective vertical stop rods 18 inside the corresponding crossed openings 14 and 15 to limit the angle of rotation between the spherical enclosures 1 . further , when rotating the spherical enclosures 1 relative to each other , the locating pegs 221 of the second locating plate 22 are moved over the tapered surface portion 141 of the corresponding spherical enclosures 1 , thereby causing the fastener 2 to be tightly fastened to the spherical enclosures 1 , and therefore the two spherical enclosures 1 are secured together . after installation of speakers ( not shown ) in the spherical enclosures 1 , electric connectors 3 and ribbon cables 31 are installed to link the speakers and to connect the speakers to the audio source . further , because the ball 23 can be rotated in the ball socket 24 , the user can adjust the angular positions of the spherical enclosures 1 . although particular embodiments of the invention have been described in detail for purposes of illustration , various modifications and enhancements may be made without departing from the spirit and scope of the invention . accordingly , the invention is not to be limited except as by the appended claims .