How to do a really good carpeting job around subs?

Referring to this picture: https://www.the12volt.com/installs/6.htm  done by the12volt himself...

How do you get such a nice carpeting job around the subs? I realize that they are flushmounted and I know how to do that (use two baffles) but how did he get the carpeting to look so smooth around that circle opening to the sub? Doesn't carpeting crinkle and get messy when you try to go around a circle? With vinyl, you can stretch it so you don't have this problem, right?

I really love this and I had planned on doing carpeting around my subs but I want it to look this good!!! :)

Thanks!

Cut out the center of the circle about 2" away from the edge and cut seams into the edge of the remaining 2 " of carpet. Install the subs and the sub will hold the carpet down and allow for a smooth carpet installation.

cutting seams will make "flaps" right? won't these flaps overlap with one another causing bulges? (that was why I mentioned cutting out very small wedges - no overlapping but this would require great skill to make sure the wedges aren't too big and show the MDF through them)

any idea what kind of carpet that is? it looks too plush to be the cheap automotive carpet and not plush enough to be normal household carpeting... is there something in between? it doesn't look like tweed, although I think I might end up using tweed cuz it looks really good.

:)