You know, I've recently given some thought on some of the advice given as part of this thread. It has struck me that the key to volume at the crown is to put the rollers/round brush "on base" as opposed to "off base", as explained in the link provided by Temptasia. I've been experimenting, and I find that this really does make a big difference, both with rollers and with the round brush. I used to not pay attention to how close to my scalp I was putting my round brush while drying. Now that I pay attention to making sure that it's "on base", I get much better results. Same with rollers, and I get less roller lines that way.