| First thing I would try is a single dot of Elmer's White Glue applied in the exact center of the dome, on the outside. The dot would be the size of a round wooden toothpick, cut off at the beginning of the taper. Dipped in the glue, the end of the toothpick will form a bubble of the exact size needed. This stuff is removable, with alcohol as the solvent. The commercial name is Poly Vinyl Acrylic or PVA.
If this addresses most of the problem apply a dot on the inside of the dome in the center. These dots will remain slightly visco-elastic, essentially forever, and will exhibit their final properties after about eight hours drying time. This dot should affect the hemispherical ringing of symmetrical, odd order modes. These are unnatural sounds, mostly providing a hiss to all other natural, asymmetrical sounds that occur within the various frequency ranges that excite the even order symmetrical hiss.
If this is all mostly satisfactory but you notice a slightly latent character to the transients, a small circle of MicroScale Gloss Paint from your local railroad hobby store, applied over the dot and in a radius about 3 to 4 mm around the dot, with a small, fine haired, well drained brush will repair the transients without allowing the symmetrical standing waves to reform. You can also apply a 3 to 4 mm wide band of this stuff on the suspension of the dome, right at the outer perimeter of the free material, before it enters whatever form of clamp is used.
If none of the above works you are doomed. Even my full treatment is not enough to completely remove the metallic scrape that a metal dome can apply to sounds. But, these are the horrid metal domed tweeters found in some inexpensive direct radiator systems... like the ones in my Buick!!!!! |