Turning the door into a proper speaker enclosure is one of the most important part if you want any midrange/midbass performance out of your speakers. Clean sound is one thing. Soundstage is next level stuff that basically puts you in a world of music. Time alignment basically is a head unit or sound processor tuning option that delays time timing which the speaker plays so every soundwave from each speaker in your car reaches your ear at the same time. If you do it right, it will be like a concert on your dash where you can seperate every musician and instrument in their proper locations with the singer dead center along with the drums feeling like they are outside past your windshield sweeping across your dash with a drum solo very loudly where it thumps your chest(thats midbass nothing to do with subs)
