Ghost:
Love ya bro, but our base defense is NOT the Under. And it is certainly not the 4-3 over cover 4 of Narduzzi.
It's the Parcells 3-4. Okie front, cover 3.
I defer to your greater wisdom, GS. Could you elaborate on some of the differences between those? (Doesn't have to be in this thread - I'm just genuinely curious.)
With your blessing bro I'd make a new thread going into it with pictures etc. Let me know. For now the cliffs notes version is this:
Parcells 3-4 is a 2-gap front. "DE's" are really DTs, "OLBs" are DE's that can drop into coverage. Against the run, every player in the front 7 is responsible for 2 gaps, and the "OLBs" are the force players versus the run. It's a 5-2 defense but the 2 DE's can drop making them technically OLBs.
4-3 Over Cover 4 (as narduzzi runs it) aka the "Miami" 4-3 is a single gap front. The 4 linemen have only one gap responsibility, and have to immediately pressure that gap. Everyone in the front 7 fills a gap on the line, and forces the ball carrier to run sideways via a technique called "spilling" where the safety to that side comes down as the force player. The cover 2 version is the same, except the Cornerback is the force player.
The 4-3 Under Cover 3 as from Pete Carroll is somewhat a combo of both the above. On one hand, the 4 DL are responsible for one gap. On the other hand, they SAM linebacker and the Weak DE (elephant/LEO) use a "box" technique against the run. What this means is like their 3-4 counterparts, they are the run force players, setting the edge and pushing the ball carrier back into the teeth of the defense.
The Bear front is the same as the Under front, but the Strong DE slides over one gap, and the NT plays a 2-gap 0 technique.
A note on all of these: changes in coverage in each of these three effect the change in who can be the force player.
A second note: Miami runs about 5 different fronts, not including their blitz packages. We are a jack of all trades master of none. It's a CLASSIC sign of a staff that is green. I've said it for three years that we run way way way too much, and thus none of it works well, and is easily exposed by BCS level coaches.