|A technique used by acoustic guitarists like Michael Hedges and Ani DiFranco is the slap harmonic (S.H.). It’s a sharp, percussive harmonic chord made by reaching over the top of the neck with the right hand (see Photo 1) and slapping the strings with the middle or index finger, whichever is more comfortable for you (see Photo 2). This technique works best at the locations of the natural harmonics (the 12th, 7th and 5th frets) and it is usually used in open tunings.
Make sure that you are tuned to DADGAD and try a slap harmonic on the 12th fret:
1. Line up the middle or index finger of your right hand directly over the 12th fret. It must be aligned perfectly with the fret wire.
2. Now, keeping parallel to the fret, lift your finger away from the strings.
3. Finally, strike directly above the 12th fret with a sharp snap of the wrist, pulling away as soon as you make contact with the strings. You don’t need to strike hard to make the harmonics sound and only slightly harder to produce the percussive sound of the strings snapping against the fret.
Following the steps above will produce a chord that has a very different sound than fretted chords, or chords produced by the other types of harmonics. Since it takes only your right hand to perform slap harmonics, this technique is useful when you want to create a two-part texture. If your right hand slaps harmonics on the lower strings, your left hand is free to tap notes. Try this example (still in Dsus4 tuning) of slapped chords supporting a tapped melody.