Using an NP electrolytic is OK if you need a large value cap (>47uF) for a woofer low-pass filter.
A good manufacturer will take into account the ESR of capacitors when designing crossovers.
There will be a deviation from the intended design if a film cap is substituted for an electrolytic, and it may or may not translate into an improvement.
i am willing to take that gamble.
lol
seriously I don’t know how much ESR a cap will have for this application.
those ALCAP caps say they are low loss as well.
so I’m guessing the designer wanted the cap not to alter the capacitance across all frequencies
That little black “cylinder “ is an inductor
Part of a notch filter with a resistor and a capacitor for the bass , it’s a really thin wire probably 0.16 mm and 2.0mh
Used a lot in many ProAcs
A friend of mine has the original R1. He played them too loud and damaged the xover. A couple of buddies of mine are audio techs and measured all the components and drew the diagram. The speakers were restored and sounded great. Then I too found a pair of cabinets WITHOUT the xover so I built new xovers according to the schematic. They sound great!