Hi Ojdeteos,
Yes, its a little obscure how the reviewer puts it ;) but my understanding is..
"Tidal is unusual in that it manufactures electronics as well as speakers. Perhaps for this reason, the Sunray can be configured a number of ways, including with its active external crossover and extra channels of amplification."
< Can be configured as you wish--basic, passive bi-amp (internal crossover), OR active bi-amp utilizing Tidal's LPX (external crossover) plus additional amp/s--but of which I believe is available separately at extra cost.
"The crossover isn't necessary for using the speakers, but it comes with them nonetheless."
< I think its the internal passive crossover that the reviewer made mention of here, and that it could be by-passed when driven in basic full range mode w/single stereo or mono amps.