Yep a sub crawl is no replacement whatsoever for a sub with builtin EQ. But you will see that in time Pirate, and eventually when you get a sub like the 1200R after countless disappointments you will understand what me and Iggy are talking about.
Most rooms have a very skewed response curve, and simply finding the best spot to place the sub will most definitely not fix the sound curve. Especially when your placement is limited to only 3 positions.