A narrower air stream hitting the bowl will produce denser vapor. The SSV has this in spades with the small exit opening in the heater cover. Because of this, SSV hits are more dense (higher vapor/air ratio) than the DBV, with its wider opening. The vapor/air ratio is not nearly as high with the Extreme, due to the cyclone bowl's large size, and the fact that it's so easy to stir up the herb in that bowl with your hits. Load the elbow screen and hits are denser, since you're packing the herb in the screen and it stays put, instead of moving around as it does in the bowl.
where the ssv for example is a straight shot through all of the bud at once?
Not all of it. You get that more with the DBV. With the SSV your air stream is narrow and doesn't cover the whole bowl. You can either load a large amount, giving the air stream a deep bed of herb to vaporize (in one spot), or load less and move the bowl around during the hit, exposing more herb to the hot air stream.
