Why did dome midrage and planar speakers disappear?

[Feanor]

Thanks! That was very helpful. I am trying to build another speaker and have some Dynaudio midrange domes lying around. So I thought if they are no good then I shouldn't be using them.

Thanks~

Not no good! They might be very good indeed used properly. My only point is that cone drivers are the favored design these days for the midrange versus dome midranges.