I've previously recorded vocals in my walk-in wardrobe.
With all the hanging clothes and doors closed and couple of blankets, it makes a fairly dead "booth", but I got a new large diaphragm condenser mic and thought I'd make my own reflection filter also.
I wanted to make it as lightweight as possible for balance and minimise strain on the required bracketry. I was able to use three materials: coreflute, aluminium flatbar and acoustic foam.
I only finished it today so I haven't had a chance to try it. Hope to re-do some vocal tracks this week.