Took the grille insert that @mbarvo made and turned it into two parts to make it easy to change the pattern of the grille to the infill select. You'll want to go to the original (https://www.printables.com/model/583162-magnetic-grille-for-drop-bmr1-nearfield-speakers) and download the mount file as I made no changes to those.
When printing you'll want add the inside and outside files at the same time, this should hopefully center them together. All you'll need to do is change the print settings for the inside object to not print a bottom and top layer. After that you can mess with whatever infill design you want. I uploaded some print files to hopefully make the process a little easier.
The author remixed this model.
Took the grille insert that @mbarvo made and turned it into two parts to make it easy to change the pattern of the grille to the infill select. I also simplified the model.