Begin with the signal path.
Your music source feeds an amplifier, which drives the loudspeakers. Some products bring parts of that chain together; others keep them separate.
Passive keeps amplification separate.
The passive models use an external amplifier. The panels of the Final 1300, Final 1500 and Final 1700 take an external bass for low frequencies; the Final 3200, Final 3300 and Final 3900 use full-range panels.
Integrated bass adds a bass loudspeaker.
The Final 1550 and Final 1750 combine an electrostatic panel and a bass driver. They still use an external amplifier. Confirm the current versions with your dealer.
Integrated amplification brings it all inside.
The Final 1570 and Final 1770 incorporate bass, amplification and DSP. Your dealer can explain the source connections and volume control needed for the version you are considering.
