I am not so sure. The raison d'être of these designs is controlled and relatively narrow horizontal dispersion across a wide span of the frequency spectrum. That is achieved in the 90 by using multiple HF, MF and LF drivers and DSP. In the 50, there is a similar arrangement for the MF and LF ranges but , in the 50, they use an adjustable (and cheaper) acoustic lens for HF. This is perfectly reasonable and the limitation is simple: One cannot re-aim the controlled dispersion to another MLP without rotating the speaker, as one does with almost any other speaker on the market.