I get this question a lot from guys, and I guess things are not making sense, so I'm going to try and set the record straight with this post. First off, we must understand, that everything is done for a reason. Solo and Special Coverages are overloaded zones pushed to the passing strength to help with 3x1, 3x2 and 4x1 offensive sets. So let's take a look at what each coverage is, and why each coverage is needed.
Solo, often referred to by old-school Quarters coverage guys as "Poach" is basically Blue (2 read) to the number one and number two receivers on a trips side. In the TCU 4-2-5, the read side corner, strong safety (SS) and free safety (FS) will all play blue coverage to the number one and two receivers. The number three receiver strong is handled by both the read side linebacker and the away side safety. The weak side corner will cover the single receiver man-to-man, and the away side linebacker (LB) will take the running back in man coverage also.
Here are the individual rules:
Corner: All of 1 vertical/Swing deep of 2
FS: All of 2 vertical; 2 not vertical and in, rob curl to post of 1, 2 not vertical and out, man 1.
SS: Curl/Flat/Swing deep of 3.
LB: Strong hook, short wall 3.
Corner: Man #1.
WS: Deep 1/2, all of 3 vertical.
LB: Man #2.
Pros of Solo Coverage
Right off the bat you can see that the simplicity of the coverage is that the read side needs no new teaching (with the exception of the wall off technique by the read side linebacker). This is nothing more than the simple "X-out" concept many loaded zone coverages employ. The away side is also a relatively simple assignment as well, since kids have been playing man-to-man since they were first put on playgrounds. Also, the run support to the read side is very solid, with the SS still being in a great position to force the football from his normal alignment.
Cons of Solo Coverage
The weak side run support is the biggest issue I know of with Solo coverage. The WS is put in a bind in that if the number three receiver goes vertical, he MUST honor that release, leaving the force player late to the party on the away side. However, you must remember, the read side is always set to the wide side of the field when the ball is on a hash, so there is not much room for the offense to maneuver to the single receiver side. In the middle of the field though, I would say this could be a recipe for some big gains, particularly if your opponent is used to sending its receivers vertical. The other issue is the WS's ability to get over the number three receiver when he is running vertical. Another tough issue, is when the vertical of three becomes a corner route. There is some much needed seven-on-seven time with Solo coverage. Another issue that arises is that most times the single receiver in a trips set is the best receiver of the bunch, and if they pit him against your corner, you could see some mismatches based on personnel.
Another con is flood routes to the read side. Depending on how you declare receivers vertical, you can be caught in a pinch if you are not careful. The flood route is as dangerous as one may think, but does take some work to perfect.
What Solo isn't, Special is. That's about as simple as you can put it really. Special is an excellent 3x1 coverage, that is also an "X-out" concept, however this time the manned receiver is on the read side instead of the away side.
Corner: Man #1.
FS: All of 3 vertical; 3 not vertical and in, rob curl to post of 2; 3 not vertical and out, man 2.
SS: All of 2 vertical, swing deep of 3.
LB: Strong hook, all of 4 vertical.
Corner: Play call (can play sky/cloud,bronco etc).
WS: Play call.
LB: Depends on call.
The away side has a ton of freedom. You can do any of the following options.
TCU would refer this as cover five, however in my system when the corner is the flat player, then we simply tag it Cloud. In cloud, the corner is the flat player, and is also the swing deep of two player. The WS then becomes the deep 1/2, all of one vertical player with the away side LB playing the weak hook to curl, and has all of number two vertical.
Sky is simply the opposite of cloud for the WS and weak corner. I like Sky coverage because it has safety run support, and I prefer to have my safeties force instead of my corners.
You can run blue coverage to this side as well, but you do have a rough time defending the curl from blue coverage, so I only recommend this if your opponent does not attack the curl area, or if you on a hash.
Bronco is a better option than Blue, because you can tighten the WS's alignment to assist in supporting the run. Bronco is played many ways, I simply man the corner on the number one receiver and the WS will take all of number two vertical or out.
Solid is the way to truly get 3x1 teams out of trips. In Solid you can run Solid Backer, Solid Smoke, or Solid Cobra. All three are shown below.
As you can see, the defense is taking advantage of a three-on-two match up and attacking the offense with this match up. Solid coverage is one of my favorites because the offense does not expect this from a zone look on the backside of a 3x1 formation.
Pros of Special Coverage
The top reason I like Special is the fact I can cover my opponents best receiver with two players. You can mix and match either having the safety over the top, or the corner, thereby keeping your opponent's quarterback (QB) guessing as to which player is responsible for what zone.
The addition of Solid coverage on the away side is another great reason to play Special Solid. Attacking the offense is what the defense should ALWAYS have in mind, and Solid does just this.
The weak side run support in Special is much better than Solo because either the corner or WS has deep help to their side. This frees this player up to attack the line of scrimmage (LOS) on run looks, as well as helping to play the cutback on runs to the strong side.
Cons of Solo Coverage
The cons most often come to the read side. The read side run support is tricky at best. The SS should be the force player, but can easily be influenced by the release of the number three receiver. The FS and read side LB can alleviate this somewhat, but the run support to that side takes some work.
The cross-training of the SS as a corner also takes some work, but is not as tedious as many may thing. However, this does add to the complexity of the coverage.
So, looking at what both these coverages are and aren't, really shows why both are a compliment to each other. The biggest reason to run both, is quite easy, run support. I did not run much Special for fear of the complexity and did just fine, however flood routes and away side runs did take their toll on my team. I would have benefited from installing Special, to combat the problems that are inherent to Solo coverage.
Yes, both coverages take time to implement, and I recommend installing Solo first, as it is an easier coverage install. However, I do think, as the season rolls along, you should have Special installed by your third game at the latest. This is just my opinion, and obviously the earlier the better.