Canceling a series of linked jabs into fb

I’ve never had any trouble canceling normals into specials until I tried Roses cr.lp, cr.lp, cr.lp xxx lk.Soul Spiral. I got no problem doing cr.lp xxx lk.Soul Spiral or doing similar combos such as Seth’s cr.jab,cr.jab, xxx mk.legs or sagats cr.lp xxx TU. For whatever reason though, adding in the additional cr.lp’s seems to kill my ability to cancel the third. Any tips for getting the hang of doing this more consistently?

You’re probably chaining the jabs instead of linking them

Rapid-fire light attacks are so turbo-licious because they are “chain cancelable.” This means you can cancel one of them into another one before the first one’s animation is actually finished. Unlike many other types of cancels in SF, this can be done even on whiff (the first attack missed, did not connect at all, neither hit or block). A light attack that was chained into (the previous light attack was chain canceled to it) loses its ability to special cancel or super cancel.

(Note that only some and not all light attacks can be chain canceled. It’s different from character to character.)

Rose cr.lp, cr.lp, cr.lp xx lk spiral
Rose’s cr.lp is chain cancelable, which is why you couldn’t do the special cancel at the end. In order to preserve the special cancelability of the last light attack in a series of them like that, you need to “link” the last two together: in this case, the second into the third. This means that instead of chain canceling the second into the third, you actually need to let the recovery animation of the second one finish, and then get the third one to connect while your opponent is still stuck in his hit-stun animation (or block-stun animation). What this comes down to in real terms is that you’ll need to delay your third input (press of the jab button) a split-second instead of just pushing it again right away. Basically you need to time it, you can’t mash.

Let’s take a quick look at your other two examples to see why those were working for you.

Seth cr.lp, cr.lp, xx mk legs
The move that you’re special canceling is the You’ve been linking the second cr.lp into it.

Sagat cr.lp xx TU
There’s only one light attack happening so of course no chain cancel could ever take place, and the single cr.lp can always special cancel just fine.