Re: H/U xover vs. passive comp xover
the HU filters are applied before any amplification, whereas the passives are post-amplifier.
if you have 2 way components, this is a 2 way crossover (highs, and lows)
for the HU filter, this would use 2 channels, 1 for high, 1 for low.
the passives only need 1 channel -- the output is split* later.
That said, if you have a subwoofer or midbass, you can use the HU's filters to blend the component set and woofer together, while using the passive crossovers to blend the tweeter and midrange together.
This arrangement is common and favorable -- the components typically are no where near as loud as the woofers for bass and they don't really contribute to the bass (and can even reduce the bass) and the bass is often stressful, increasing distortion.
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