First tune the 6th string to a D using the MIDI
note below.
6th string
D tuning note
When using the basic
tuning method for standard tuning, you would play the 5th
fret on the 6th string and tune the 5th string open to that.
In Drop D tuning, you are going to play the 7th fret on the
6th string, then tune the 5th string open to that. From there,
you will tune everything the same as standard tuning. You could
also tune the rest of the stings using harmonics.
Basic
relative tuning for Drop D
Page 1, getting into Drop D from standard guitar tuning
