It is all to do with waterfall...driver resonance is what messes up treble. Soft domes treated with damping material on the fabric work well.
It is often a fight between on one hand stunning brochure quality frequency response plots versus a not so perfect treble rolled off above 12 Khz. If you let the frequency reponse plot dominate your design choice then you inevitably end up with a metal or very stiff type tweeter and that is how you get a waterfall with resonance.
Most people know as a rule of thumb that soft dome tweeters are smoother than metal ones...now you know why.
It is often a fight between on one hand stunning brochure quality frequency response plots versus a not so perfect treble rolled off above 12 Khz. If you let the frequency reponse plot dominate your design choice then you inevitably end up with a metal or very stiff type tweeter and that is how you get a waterfall with resonance.
Most people know as a rule of thumb that soft dome tweeters are smoother than metal ones...now you know why.