What does “w/” mean? [closed]
The B strings tuned w/ low E 7th fret harmonic-(6th string,7th fret).
The shorthand w/ is used to mean with.
2 pieces toast w/ gravy
Is a shorter way of writing "Two pieces of toast with gravy."
The B strings tuned w/ low E 7th fret harmonic-(6th string,7th fret).
means "The B strings tuned with low E, 7th fret harmonic . . ."
Edited to add: As Denis de Bernardy correctly notes in the comment below, w/o means the opposite: without.