Or, how about going fully active? Buy a digital cross-over from the very high quality likes of Xilica (without costing a fortune), and make slopes, Q’s, delays, gains etc. on the fly, from the listening position. You’ll need extra amps for each pair of drivers/frequency section, sure, but they needn’t be as expensive being freed of looking into a more or less heavily driven passive XO and instead firing directly into the driver. Slopes up to 48dB/octave, without the added complexity of a passive design, and with the filtering done pre-amplification on signal level there’s no meddling with a full-wattage input (into the filter) and fluctuating filter values.
I'm using a fully active set-up myself with a Xilica digital XO (36dB/octave L-R for mains and 36dB/octave Butterworth high-pass on the subs), and it's a sonic delight.
I'm using a fully active set-up myself with a Xilica digital XO (36dB/octave L-R for mains and 36dB/octave Butterworth high-pass on the subs), and it's a sonic delight.