A device for housing a sound-emitting transducer including a housing and a cap. The housing has a chamber defined by a cylindrical sidewall and an endwall with apertures. The cap mounts to the housing, and has apertures that can register with the apertures in the endwall. A groove is formed between the cap and teeth formed at its circular outer periphery. The cap's circular lip is inserted into the groove by deforming the cap slightly. Thus, relative movement is permitted between the cap and housing for registering and de-registering the apertures on the cap and housing. This controls the volume of the sound-emitting transducer.