| 摘要 |
1352883 Headsets INDUSTRIAL PATENT DEVELOPMENT CORP 19 April 1971 [18 March 1970 5 June 1970] 24291/71 Heading H4J A pair of headphones for four channel listening has two receiver transducers in each headphone. In a first embodiment, two housings 20, 22 of moulded plastics material are pivotally mounted by pins (24, 26), Fig. 1 (not shown), on a resilient support (16) through which conductors may be threaded. Each housing 20, 22 has an inwardly facing opening 28 covered with a perforated disc 32. Each housing 20, 22 carries two speakers 40 and 42, 44 and 46 secured by plastics backing foam 48, 50, 52, 54. Speakers 40, 42 face each other and are spaced apart by the diameter of the opening 28. In use, the support (16) extends across the top of the user's head and the speakers 40, 42 are on a common axis extending from front to rear. Speakers 44, 46 are similarly arranged. Stereo separation between the speakers in each housing 20, 22 is improved by a reflective membrane 66 adjustable by a threaded screw 62. An alternative headphone (Fig. 4) comprises an enclosure 70 in which are two backto-back moving coil speakers 76, 78. A wall 84 of sound-insulating foam separates the speakers 76, 78 and divides an opening 72 having an earpiece 74. In use the loud-speakers 76, 78 are on a common axis extending from front to rear. In another embodiment, two housings 112, 114 (Fig. 5) are pivotally mounted on a support 116 through which conductors may be threaded. Foamed plastics layers 119, 122 are provided. Each housing 112, 114 has two speakers 126, 128, one on each side of an opening and in use the axes of all the speakers 126, 128 are generally parallel with the support 116, which is worn across the back of the head. The opening has louvres 132 (see also Figs. 6, 7, not shown). An opening 134 in the foamed plastics layer 122 is for surrounding an ear. Stereo separation between the speakers 126, 128 is enhanced by an adjustable V-shaped membrane 136 of stretchable material. |
