New business idea: begin making shiny boxes that don’t even claim to do anything. The marketing plan writes itself. We won’t lie. We’ll just make sure the small print is very small indeed.
1) Whether you want reduced jitter, increased soundstage or a more (or less) “digital” sound, Placebo Audio’s products will do exactly what you expect them to. This makes for an entertaining read on the extent of the issue.
3) Placebo Audio’s products are designed to have no detectable impact on frequency response. Or anything else.
4) There’s a lot of literature on this. Within the specific field of consumer audio, you might try this. If you’d prefer something a little more clinical, you might prefer this study on the placebo effect in hearing aids.
5) The laws of physics do not apply to these products (unless you expect them to).
6) Your ears will say “I dunno”. Your brain, which can’t hear at all, will think it knows better.
Proper Discord 
Are the details to subtle for conventional measurements, or too subtle? Or is the distinction to subtle?
Oh bugger. Thanks for catching that. Fixed now.
I dunno. I like the idea of verbifying “subtle” (is “verbifying” a real word? If it’s not then “verb” should certainly be verbified). If we could subtle some conventional instruments then who knows what we could achieve in creating new evidence.