Mo, the first question obviously is whether the holy water was Catholic, Orthodox or what. I've pondered this a few minutes and don't have a technologically oriented suggestion because I've never heard of such significant changes occurring. Incidentally,"remarkable improvement in soundstage" isn't really how I would describe it. There's a relatively subtle overall expansion of ambience throughout the room, the effect of which becomes really noticeable when the surround mode is suddenly switched off and the soundstage collapses to the front.
