sound without increasing the height of the structure a still further advantage of the angled projection according to the present invention will have is that any sound reflected off the angled projection will be reflected back into the work area from which it emanates rather than upwardly towards the ceiling from whence it can be reflected to another work area this is especially true when the face of the angles projection is essentially planar in the vertical direction and for this reason the essentially planar face is the preferred embodiment the effectiveness that a screen according to the present invention can have is shown by test results which show that it can achieve a noise isolation class prime rating of 22 when tested in accordance with general services administration pbs c 2 test procedures this value is a single number rating which provides an evaluation of sound attenuation between two areas which are acoustically related by one or more paths of sound any nic 39 rating above 20 makes possible a reduction in certain space acoustical components without sacrificing what is generally regarded as necessary speech privacy in open plan designs referring now to fig4 there is shown a second and preferred embodiment of the acoustical room divider screen 10 of the present invention this embodiment uses an angled projection 49a 49b on each side of the screen 10 this embodiment is useful where sound may be generated or received on either side of the screen 10 in addition to attenuating sound which is directed at the front of the angled projection sound which is reflected off the ceiling or otherwise present will also be attenuated by the rear side of the angled projection or by the top if the top is a flat structure this substantially increases the.