Adriaan - now that you mention it, I recall that a piano/harpsichord player I dated when the world was young made a point of differentiating her perfect pitch from her perfect ear - my bad.
Mark - I knew there was some dubbing, but never knew what - though I guess it makes sense that if you're dubbing a Dead performance, you'd start w/the vocals.
I also love Dylan's singing - and Neil Young, and Kristofferson, and all those 90-year-old blues and bluegrass and old-timey cats that still do it, wavering but real. What can I say? It does it for me more than polish does.
Peter