Tarkuz, don't PAs come with passive crossover networks?
For speaker systems that need to be set up quickly by only a few people, be very compact, and provide simple audience coverage (without lots of sub-bass), a loudspeaker system with passive crossovers will be suitable.
For applications that require high levels of sub-bass and a high degree of efficiency, the active crossover is used. Note that the use of active crossovers will increase the expense of a sound system significantly.
