What are the types of audio loudspeaker terminals?

All dome materials have advantages and disadvantages. The three properties designers look for in domes are light weight, stiffness and lack of coloration/ringing. Exotic materials like titanium and berylium are light and stiff but can have ringing problems. Material like silk will ring less but can be heavier and not as stiff. It is all about trade offs. There are good tweeters and bad tweeters made with all types of dome materials. While there is a lot more to driver construction than just dome material, dome material alone can go a long way toward selling speakers, so sellers often use the most exotic dome materials and dress up tweeters with fancy lenses or covers - often without regard for other complexities. Some dome tweeters will have exotic designs such as putting a fixed wave guide (also known as a phase plug) in the middle of the dome. The theory behind this is it now gives the tweeter material two points of suspension for less cone break up or distortion and more detail.