Get an SPL meter first. There is no substitute for just building a ton of different boxes, different sizes, different tunings, different port sizes,all different orientations in your car. You'd be amazed what any given sub can do and the variety of different types of response you can get...even same box just pointed a different direction can be dramatic.
That is the thing, I have designed close to 10 different boxes for this sub, but with me being OCD, I just can not make a commitment on just one. But, you're right, the only way I will know for sure is to build different ones and see how it couples with my car. I've designed many ported boxes, tapered tline variants, and a rear loading horn.
About the tapered tline variant... when I had another set of subs, I sent off a design request to a VERY popular enclosure designer. Of course, one of the questions asked on the form was max outside dimensions. Well, what I got back was a design for a tapered tline variant for these subs using the exact max dimensions. Now, for someone who supposedly weighs your vehicle cabin geometry pretty high up in the design, how did he arrive to the exact dimensions that I gave him? This makes me question whether he actually takes cabin geometry as a major factor, but more so, the max box dimensions' geometry. Shortly after I got the design I sold the subs because I wanted to try something different, so I never built the box.
This peaked my interest and after looking at his design that I
bought, I tried to figure out how he designed it. After playing with google sketchup, I have his process of designing this alignment down perfect. For any max dimensions given, I can design this t line variant exactly the way he does. It's all about angles, 45 degrees from each corner are landmarks for every panel in the box. There are different angles for the mouth that will give you whatever kind of taper ratio you want, you can either increase or decrease the angle. I sketched up the max dimensions for my box without looking at the lengths of his internal walls, 45's etc. When I was done, I had the same EXACT lengths/ internal dimensions that he had to a 1/100's of an inch.
Anyways, going back to what you said, I think I might try this alignment first in multiple tries at different enclosures just to see how it goes. People SWEAR by the guy's work. So hopefully my questions will be answered when I hear it. Is this as simple as I thought, and the guy just gets backed up on requests and is lazy, so he uses a quick 10 min method? Is this method for real? Or am I full of shi
t and not even be in the ballpark. It could be any of these, but we'll see.