No problem, as you can see its incredibly easy to make.
If you cannot weld, don't fret, you can still make one. You need to purchase a structural adhesive and glue it together. You'd have to clean the metal very very well though, and rough up the mating surfaces with emery cloth (don't use sandpaper, miniscule particles of sand will embed in the mild steel).
Another option is to take two pieces of 2"x2" angle iron, and drill a 1/2" hole in the same place on each, then mount them on the wall with four screws each, one directly above the other, with the top one upside down, with about an inch apart, so the post of the mic arm can fit between both of them. That wouldn't look as professional, but it would work just fine.