THE most sonically dissappointing (lp) you own of great music?

I agree with mapman! I recently picked one up at a yard sale, I was blown away with the quality. Inside the booklet revealed the secret, apparently King Biscuit recorded several live events using state of the art mobile studio gear, all I know is the quality jives with the explanation. I will be looking for more King Biscuit recordings! 

That's GREAT!

Although this kind of goes against the original post?

Cheers!

Todd Rundgren's "Nearly Human".  A unique album combining songs that are about as good as popular music gets with SQ that's  about as bad as modern recording gets.

Most studio albums by R.E.M.