Quoted from red-line:
The instructions will probably tell you to layer it acrylic - grill - light box - speakers. Instead, layer it acrylic, light box, grill, speakers.
The instructions actually describe all of the different acrylic mounting methods.
A general rule is if the acrylic is clear or mirrored and it has etched detail in it, the more etched detail area there is, the better it looks if you DO NOT have the grill directly behind it. If you have a clear acrylic like the Ghostbusters Slimer or a heavenly etched mirror acrylic like South Park or Family Guy......if you can't mount the grill behind the light frame, there really isn't any need to buy the acrylic design because it will look like crap with the grill right behind it. It actually just makes the design blend in with the grill and it's barely visible.
I guess some people are afraid of kids sticking gum or pennies in the speaker holes if the grill isn't there closing up the speaker hole, but even adding some washers as spacers to go between the back of the design and the front of the grill is better than having the grill directly behind that type of design.
The LotR design looks good mounted in the standard method (as it doesn't really have that much etched detail), but it looks much better if mounted in the 3D method.Acrylic mounting (resized).jpg