loudspeaker enclosure 201 via a port tube 203 for any upward orientation of disk 205 as compared with the structure shown in fig1 the potential for other detritus to enter enclosure 201 through the port structure is slightly reduced but still possible referring to fig3 and 3 a a first embodiment of the present invention is shown according to this first embodiment a port tube 308 extends outwardly from an enclosure 301 a port tube opening 310 is covered by a port cover 309 which incorporates a flow guide 306 for reduced turbulence as disclosed in u s pat nos 5 517 573 and 5 809 154 mounting bosses 309 a which are small compared to the perimeter of port cover 309 are used to support port cover 309 the dimensions of port cover 309 are chosen such that the total cross sectional area of an exterior opening 311 around the perimeter of port cover 309 is significantly greater than the cross sectional area of port tube opening 310 as is well understood by those skilled in the art a port structure with a large cross sectional area at its outermost end serves to reduce turbulence and loss the dimensions of port.