How does a passive audio crossover get affected by two speakers

>>1132551
Two of the same speakers? Half the impedance expected by the crossover?
Give us details anon, parts, specs, objectives

>>1132551
https://en.wikipedia.org/wiki/Low-pass_filter#Electronic_low-pass_filters

for passive filters,The cutoff frequency is 1/RC

In series you'd be doubling the resistance R
so you'd be reducing the cutoff frequency effectively lowering the crossover point by half
(ie 100hz instead of 200hz)

Besides that it should work perfectly fine.

If you put them in parallel you'll double the crossover point, however you have to be careful, lowering the impedence can draw more current than your amp can supply (and 'possibly' more than the inductors in your crossover)

>>1132551
and this is for a super simple crossover.
a lot have measures to negate the affects of both the points mentioned above.