@rauliruegas , I think we may have different definitions of point and line source.
A point source is a driver that is smaller in all dimensions than the shortest wavelength it is to reproduce. I line source is a driver that is larger in at least one dimension than the largest wavelength it is to reproduce. There are drivers that can be line sources at higher frequencies and point sources at lower frequencies. There are only two drivers that are line sources from zero hertz to over 20kHz. The first is an infinitely tall one and the second is a tall or long one that both ends terminate at fixed barriers like a floor, ceiling or wall. It is impossible for a driver to be both full frequency line source and full frequency point source. It is actually very bad for a speaker the swap radiation characteristics mid audio band as the power projection is very different and will cause frequency response aberrations that vary with distance.
Both my ESL and subwoofer systems end at fixed barriers. My system is line source from zero to as high as the ESLs will go which is probably not higher than 18 kHz. Roger West won't publish that spec. I am toying around with inserting a ribbon tweeter to go from 12 kHz up. This would relieve the main amp from having to deal with the crazy impedance curve of ESLs up there and give me a little more flexibility. I will have to biamp it and add a second digital crossover.