Abstract: Therapeutically active compounds of the formula: ##STR1## wherein the variables are defined in the specification are provided.

Abstract: A loudspeaker is provided for high-quality stereophonic loudspeaker systems intended to be positioned on the floor close to a vertical wall of a room. The aim is to reduce distortion due to that part of the reflected sound which arrives from substantially the same direction as the direct sound. Therefore the sound radiating surfaces and the loudspeaker casing are so arranged that the reflected sound from the floor and the wall arrives substantially in phase with the direct sound up to at least 800 Hz.The loudspeaker has a casing with a side wall (2), a top wall (4) and a bottom wall (6). A loudspeaker unit (7) in the side wall (2) is the sound source for at least the range from 50 to 150 Hz. A loudspeaker unit (9) mounted in a horn-type casing structure close to the bottom wall (6) is the sound source for at least the range from 300 to 800 Hz.

Abstract: A loudspeaker is provided for high-quality and particularly stereophonic sound reproducing systems positioned close to a wall of a room. To reduce distortion due to that part of the reflected sound which arrives from substantially the same direction as the direct sound, the positioning of the sound radiating surfaces is such as to make the reflected sound from the wall arrive substantially in phase with the direct sound throughout a large frequency range, while at higher frequencies the reflected sound is attenuated by a sound absorber.The loudspeaker has a casing with a rear wall (5a). Loudspeaker units arranged to be the sound source for mid-range (12b) and/or high (14a) frequencies has the sound radiating surfaces (12b, 15a) at short distance (D2, D1) from the plane of the rear wall (5a) and facing slantwise forwards.

Abstract: A loudspeaker has a rectangular casing providing a frontal wall in which are mounted a plurality of speaker mechanisms responding to differing frequency ranges. The high frequency speaker is oriented so that the axis of radiation is inclined upwardly and to one side of the normal to the front wall. In the preferred embodiments a lower frequency speaker, such as a low and midfrequency speaker, is similarly oriented but to a slightly lesser angle of inclination. The front wall has a conically concave portion the axis of which is similarly inclined, to accommodate the lower frequency speaker, and the high frequency speaker is mounted on the conical wall portion. Some embodiments also have a separate low frequency speaker. Two such speakers are located, widely spaced laterally from each other, adjacent the wall of a room with the left hand speaker radiating to the right and the right one radiating to the left.

Abstract: A loudspeaker combination comprises a rectangular casing having mounted on its top wall a midfrequency speaker and two or more high frequency speaker devices. The midfrequency speaker is oriented generally upwardly with an angle of declination of less than 45.degree. from the vertical. The high frequency speakers are oriented generally horizontally, with a slightly upward inclination. The axis of the midfrequency speaker and of at least one of the high frequency speakers are slanted sideways in the same general direction. This latter speaker or speakers radiates at least substantially one-half of the total high frequency sound energy of the loudspeaker combination. The remaining high frequency speaker or speakers radiate in different directions, preferably toward an adjacent wall or walls. In one embodiment the midfrequency speaker device also radiates low frequency sound; in another, a separate low frequency speaker device is provided.