Passive PA speaker
The advantage of choosing a passive PA speaker system is that you can set the system amplifier on the rack of the cabinet and completely control the speaker. Many modern power amplifiers (such as LAB PLM12K44 and RAM S6004DSP) contain advanced built-in DSP which allow you to adjust the whole system in the audience hall seat. If it is a large system, it is really save you a lot of time for installation and adjustment. You don't need to supply power for each speaker. There is no complex power distribution system. If you use a strong enough power amplifier, it is not so difficult as you imagine that add the speaker to the system.
Advantages of passive PA speaker
The centralized commercial power amplifier
rack provides a central point for speaker controlling.
A single passive speaker is generally cheaper than a single active speaker.
Passive speakers are usually lighter than the similar active speakers.
Don't need to supply power to every speaker, so the installation time and wiring can be shortened for large systems.
Complex DSP on some power amplifiers can provide advanced parameter adjustment.