The woofer's sensitivity is 90dB and the tweeter is 93dB, with all else equal, I would just need to offset the tweeter by -3dB. However, I read an article somewhere that spoke about the human perceived loudness of 3dB at varying frequencies. If I remember correctly, the lower frequencies were perceived as being a more dominant change due to not only hearing it but feeling it as well, which a microphone can't pick up during testing.. So would I want to change anything? I'll have to dig up that article again. There was some known rule that it called for, like +3dB on upper frequencies by default.
You probably need to change quite a lot. I think you have a lot more design work.
Although going active makes driver selection a little easier. Correct driver selection is still important. So you still can not pick driver and woofer out of the air randomly.
The thing I think you have forgotten is the baffle step. This is the frequency at which your speaker goes from a half space radiator to a full space radiator. In other words it transitions from monopole to omnipole. This is calculated from the width of the front baffle. Below this point a 6 db boost needs to be applied to the woofer.
I would make a passive model of your crossover first. This will guide you in your mini dsp application.
The other thing is you will need to place a cap between the HF amp and the tweeter, to remove any residual DC offset from the amp, and more importantly protect the tweeter from any thumps, like turn on thumps.
The other thing you might consider is using two woofers and making this a 2.5 way. You will need three amps. A huge advantage of going active is that you can get BSC right, as it is hugely affected by room and placement. My front three all have active BSC, and this makes a massive contribution to realistic reproduction, especially speech. You will need to double enclosure volume as driver VAS is doubled. This will give you are much better and more powerful speaker.
I don't know what drivers you are using, but if the woofer has a big break up mode peak above crossover, you will need a passive notch filter between amp and speaker. This is because if you speaker has a 6 to 10 db break up mode above crossover, then your amps signal to noise ration will be effectively severely downgraded, and you will hear hiss you otherwise would not.
If you are going to use different amps for woofer and tweeter then you need to check the phase response of the amps on a dual channel o-scope driven from an oscillator. You can not assume the phase angle of amps of different design will have a zero phase angle.
Those issues are the ones I can think of now, but I'm sure their are more.
I'm in the UK now, and I'm just off to drive to Greenwich to get the boat to London to see my nephew. It is a glorious day, and we should have good high water on the Thames.
