To be honest, I recorded the first demo of my first band (20+ years ago) using a open-back combo placed in a bathroom and MIC'd FROM BEHIND USING THIS EXACT MIC POSITION. Sounded great (AFAIR...).
That pic was from a while back, if I get some spare time after work this weekend, ill set it up again and make some purple pleather chair impulses
or even just see what it sounds like.. im curious now too