Why? They sound exactly the same.

It's driving it that I'm worried about. I plan to bridge two channels
of an amp and run it into 4 ohms. I guess if the dual coils are both 2
or 8 ohms, I could wire it to look like 4.

Go with the dual 2 ohm version of the Type-R and it will be all good.


and in a sealed enclosure.



I think he was referring to the specific sub/box combo that Alpine
makes, which I believe is ported.

It may be. I got out of retail before Alpine made prefab Type-R boxes.



I was planning to buy a Q-Logic box, because I'm too lazy to make my
own, and too cheap to pay someone else to make a custom box. Are
Q-Logic boxes OK, or do they suck?

They suck. You can find prefab all MDF boxes for a single sub for about
$50.

Paul Vina