Well, I do know that Peter's fussiness about microphones was legendary. Pre-concert sound checks took hours and hours - I've seen some. Despite his perfectionism, my PP&M CDs, especially the ones of the early albums, are awful. It sounds like they're lisping on every cut.
Mary's singing sounds especially lispy on the early albums. Perhaps I should say, "Mary's thinging thounds ethsthpecially lithpy."

Get your sound advice from somebody else.

-Joe-