Amplifier XO simulation in WinISD

[Iwont Tell]

Hello, I'm a newbie with a crossover-related problem.

I'm trying to design a speaker+sub combo around the crossovers of my Yamaha DSP-A2 amp. Is it OK to use Butterworth filters and Q=0 in WinISD to approximate the filtered output of the amp? Or are the other provided filter types closer? What Q-values would be probable?

Here's what I have come up with so far:

Represented are a 10" vented subwoofer with a LP filter of 18db/oct, the same woofer in a closed box with a HP filter of 12dB/oct as a reference, and a Tangband driver in a 4 litre vented enclosure tuned to 66Hz, also with the w12dB/oct high-pass. The last one is the reddish curve.

TIA!

I:-T