what is the difference between straight harp and cross harp?
Nope, just different ways of playing the diatonic harmonica. In straight harp, or first position, you're playing in the key of C on a C harmonica. ... In cross harp, or second position, you're playing in the key of G on a C harmonica, and the low octave scale is -2 -3″ -3 4 -4 5 -5 6.