Or especially avoid corners where low frequencies love to ‘gather around and hang out’ hence why bass traps for listening rooms or studios are placed there.
Speaker cab tilted or off the ground takes away some thump of the lower frequencies also.
I butchered up a perfectly fine Bag End cab which was closed back and ported. I cut what Waldo described above, left enough for an Earcandy 8ohm stereo/4ohm mono switch plate, about 4inches wide. It’s more opened than closed. Works perfectly!!