i have two 4 ohm single voice coil subs wired in series for an 8 ohm load will my 4 ohm passive crossover still work right or would you need an 8 ohm crossover now? and can you run 2 subs through the same crossover?
yes it would still work but one thing worth noting is that passive crossovers are partial to the ohm load of the speaker they are connected to and if say , you are using a 4ohm crossover for a speaker that presents an 8 ohm load then the crossover point would be different i believe in your case the crossover point would be raised to a higher frequency.