the best one is a completely custom one, modeled with all relevant data. dimensions of the room, location of the single most important target listening position, exact performance goal, location of the enclosure (if limited to one spot or another), exact maximum enclosure external dimensions, amplifier power, speaker system it is mating up to/blending in with. every single thing affects the next and all affect the type of enclosure it will take to get what you are asking for. if you want to move forward with this project, the engineer i point all of my customers to is pwkdesigns.com. go ahead and check out some of his videos on his youtube channel. specific to your inquiry...i'd check out anything regarding his listening room system. his service minimum charge is $50. that takes forever. $60 gets red status and speeds things up to about 3 days or so. $80 and he'll pinch the loaf he's working on at that moment and get the design done. i'll help you get the correct information to him at no charge, just promise to get your review up on the forum as soon as you have sufficient listening time behind you.