Abstract: To mount a loudspeaker from one side only against a resonance panel, typically in a panel of an automotive vehicle on which the rear is, practically, inaccessible, the loudspeaker basket is formed with a holding ring having an outer thread; a mounting ring with an inner thread is secured to the holding ring, the mounting ring being formed with resilient laterally projecting gripper fingers so that, after loose preassembly of the mounting ring on the holding ring and the loudspeaker, the preassembly can be snapped through a loudspeaker opening in the panel, and the speaker then tightened against the panel by engaging the resiliently projecting gripper fingers, now behind the panel, with the rear panel surface, and screwing the loudspeaker tight. An attachment tool in the form of a bail, which can engage in recesses formed at the face of the loudspeaker, for example in holes of a sound panel, is preferably used to facilitate insertion and tightening.

Abstract: To permit mounting automobile radios and other accessories on support panels of different thicknesses with a single fitting element which determines the position of the accessory in an opening formed in the panel, the fitting element is formed with a front wall from which lateral wall portions extend at approximately right angles, the lateral wall portions being formed with an overlapping edge to engage around the edge of the opening in the support wall of the automobile; the accessory attached thereto is clamped to the front wall by spring elements which engage a tapered, serrated holding surface, the serrations being staggered in a direction extending between the overlapping edge and the front wall of the fitting element so that the spring elements, typically spring wires, will hold the fitting element, and hence the accessory by engagement with that serration which fits against the rear surface of the support wall of the automobile, in the light of its thickness.