I've never personally had any luck with overlapping points because the hump in frequency sounds unnatural to me. Not every application has this hump so I do understand the need for certain installs. I prefer to underlap and use low crossover points and shallower slopes on the sub to integrate it with the front stage.

 

If everything is in phase and within the polar response of the driver then you should never have to do that. Putting a 1/2 octave gap or so between drivers helps maintain phase cohesion and intended acoustical x-over point when setting the electrical x-over point and when one driver plays at a much higher level than the other such as when the subwoofer is 20 db more than the midbass.

 

It depends on how things are summing , you can , it may or may not sound better.

The overlap can make the phase wraps sum more blurry like a low order slope would, which may or may not be beneficial. I’m always of the mind if it sounds better than go for it , but I would at least exhaust all efforts as to why a proper alignment isn’t working. Or choose an alignment that does work would be better yet.

Instead of overlap I would look at a raised/lowered crossover point with a shallower slope to try to get the sound right

 

If all else fails I use LR -24 between sub and midbass and 80 LPF on sub and 100 HPF on midbass. Midbass to midrange I might do LR -18 with matching crossover points but no overlap. Midrange to tweeter I might do LR -12 and matching crossover points. Works for me at least, usually.

 

You won’t get cancellation if drivers are inphase at the crossover points, if you do you need to visit phase and/or time alignment ??

 

Thanks to all of you. I've read and considered all of these responses. I think I'm just going to have to try a bunch of different things, and see for myself. I think each of these suggestions might work great... or terribly, completely based on the system which these things were being used with...