Process for assembly between a crystal, on the one hand, and on the other hand a bezel comprising a notch for housing said crystal, for the use of said crystal in a timepiece as a vibrating element radiating and diffusing an acoustic signal emitted from a vibration source, such as a striking work, music box, or suchlike, and transmitted to said bezel, and/or to a case middle, characterised in that: - in order to increase the sound level, there is determined an appropriate number of unconnected junction zones intended to form together the only mechanical connection for the transmission of vibrations from said bezel to said crystal, to limit the attachment of said crystal to said bezel to said junction zone or zones, so as to permit free vibration of most of the periphery of said crystal, in a peripheral space between said crystal and said bezel outside said junction zones, without impeding said free vibration of said crystal, and outside which junction zones said crystal is at a distance from said bezel, - said peripheral space is closed, at least outside the surfaces where said crystal and said bezel are joined by said junction zone or zones, in a sealed manner with sealing means, said sealing means including at least one flexible gasket or a silicone joint or similar, and/or at least one elastic membrane or an elastic sealing strip, deployed between said bezel and said crystal and not impeding the vibrations of the latter, - said junction zone or zones are created from an assembly formed of a said crystal and of a said bezel, or by restricting direct contact surfaces between said crystal and said bezel by the peripheral removal of material from said crystal and/or from said bezel, and/or by the insertion between said crystal and said bezel of at least one support block forming a mechanical connection for transmission of vibrations between said crystal and said bezel only at said junction zone, and moving one away from the other outside these points, and there is selected for said support block a material which transmits the vibration of said bezel to said crystal without damping said vibration, and which is a material or ceramic or the same material as said crystal, - said crystal is secured on said bezel by pressure and clamping at each junction zone in order to transmit to said crystal every vibration communicated to said bezel; - in said peripheral space outside said junction zone or zones, said crystal is kept at a distance from said bezel in order to permit vibrations of said bezel 32) there without interference. - in order to increase the sound level, there is determined an appropriate number of unconnected junction zones intended to form together the only mechanical connection for the transmission of vibrations from said bezel to said crystal, to limit the attachment of said crystal to said bezel to said junction zone or zones, so as to permit free vibration of most of the periphery of said crystal, in a peripheral space between said crystal and said bezel outside said junction zones, without impeding said free vibration of said crystal, and outside which junction zones said crystal is at a distance from said bezel, - said peripheral space is closed, at least outside the surfaces where said crystal and said bezel are joined by said junction zone or zones, in a sealed manner with sealing means, said sealing means including at least one flexible gasket or a silicone joint or similar, and/or at least one elastic membrane or an elastic sealing strip, deployed between said bezel and said crystal and not impeding the vibrations of the latter, - said junction zone or zones are created from an assembly formed of a said crystal and of a said bezel, or by restricting direct contact surfaces between said crystal and said bezel by the peripheral removal of material from said crystal and/or from said bezel, and/or by the insertion between said crystal and said bezel of at least one support block forming a mechanical connection for transmission of vibrations between said crystal and said bezel only at said junction zone, and moving one away from the other outside these points, and there is selected for said support block a material which transmits the vibration of said bezel to said crystal without damping said vibration, and which is a material or ceramic or the same material as said crystal, - said crystal is secured on said bezel by pressure and clamping at each junction zone in order to transmit to said crystal every vibration communicated to said bezel; - in said peripheral space outside said junction zone or zones, said crystal is kept at a distance from said bezel in order to permit vibrations of said bezel 32) there without interference.