Mark,
I actually have xover-pro and I've played with it a couple of times. How do you go about selecting the order and type of crossover? Is there something in the drivers' frequency responses that you can just tell by looking at them? Or do you perform multiple iterations using different orders?
The first thing is to pick drivers whose roll off just need a little touching up.
Look carefully at the frequency response graphs of the drivers. Be careful of Far eastern manufacturers, they are prone to embellishing their data.
Carefully look at the roll offs and see what the order of the roll offs are bearing in mind that the order may change. For instance it is common for tweeter to start with a first order roll off and change to second or even third order.
The next thing is to look for cone break up modes, to see if you will need a notch filter.
After you look at all that then you get an idea where the crossover needs to be. I like to have tweeters down at least 24db by Fs.
So if you have a woofer rolling off second order and a tweeter rolling off first order, the you need a first order low pass filter and a second order high pass filter to make a symmetrical crossover.
You need to make sure the combined slopes have identical orders.
Start by choosing orders and setting a frequency and orders, and then substituting components as required to flatten the response. Always experiment with and without woofer zobel networks.
If you need to change orders you can change the Q of the filters by adding resistance to the inductors in high pass filters, and to the capacitors in the low pass filters. Xover Pro does not let you add series resistances to inductors and caps, but you can cheat by adding it to the internal resistance of the components, and remembering to place what you add to the circuit when you build it.
You can only pad tweeters and mids not woofers. So you can not choose a woofer with higher sensitivity then your mids and tweeter. You use the L-pad program for this.
Always check the phase responses and see if the drivers are closest in phase with reverse polarity or not. Always check for best output a crossover with both polarities in the finished speaker. It is a good sign in a design if phase aberrations at crossover are 90 degrees or less. Remember however that flat frequency response trumps everything. The trick is getting to that point with the least violence to phase and time.
It will take you a while to get the hang of it.
Remember final voicing is done by ear, but when you get experience your design will get you very close.
