Does anyone know the concert pitch tuning of a twelve-string guitar? Is it a lower pitch than the six-string guitar? I notice that if I play from the same chord diagrams for songs that use a twelve-string guitar on a six-string guitar, they don’t sound right. In other words, a C chord on a six-string becomes (hypothetically) an A chord on a twelve-string.This has always bothered me. Another thing: what is the preferred key for harmonica to play folk and blues? I used to have a harmonica in the key of C, but couldn’t seem to get the right sound for blues. THANKS!