I need some help-I know a little about bass,but i need more midrange /main speaker design info!

when i search for midrange design,speaker position,and phase i get a whole lot of hifi nonsense,'phase control on ur plate amp' 'blah blah our speakers are phase perfect' etc etc.

I need-
-phase info regarding comb filtering,distance between woofers
-'overlap' with low order crossovers and effects -low vs high roll off filtering
-other issues such as horizontal positions of speakers vs vertical,dispersion etc

( + your personal experience, LR 24db/octave filters LOOK GOOD in theory,but how do they compare to the simplicity of certain systems with 1st order)

The only one i could find was ESP's phase guide but its so in depth i was scared off and left it for later when i feel like doing some study.\\\

No need to write much,just links will do!

Im sure Adrian will have a link or 3 for me,its just i cant find them yet!

According to my memory,the JBL pdf file available at PI speakers was mainly Pro usage ,not so much home speaker design and phasing etc...

Cheers all
Mike.e *wanting to learn more midrange*