# How do you make the cool sound by touching the string with your index finger?

I watched a guitarist on YouTube, and he fingerstyles and arranges his music for covers. I was watching one of his videos, and he was playing, then he took his index finger and tapped the string above the soundhole up along the neck and it made a really cool sound. I don't know how he did it.

This is the song he was playing when he did it. You might know what I am trying to ask.

• Are you asking about the sounds at 0:43 in the video? Nov 24, 2020 at 16:52
• @Aaron - between 0:39 and 0:43, I guess.
– Tim
Nov 24, 2020 at 17:30

He didn't "tap" the string with his index finger. He placed his index finger on the string at a specific location and plucked it with the other finger(s) of his right hand. This uses the principle of harmonics as Tim pointed out. There are several places (in theory an infinite number) where you can excite a harmonic. On the open string the most common ones are at the 12th, 7th, 5th and between the 3rd and 4th frets. When you fret a note these same harmonics can be excited by touching the string at some fraction of the length between the bridge and fret, 1/2, 1/3, 1/4, 1/5, 1/6, etc. These can be excited by touching the string and plucking it or gently tapping at these nodal locations.

• +1, better answer, because it points out the several nodes on a string. Nov 24, 2020 at 21:16
• @MichaelCurtis - I expected that to be picked up on. OP is a beginner, and asked specifically about that video. I didn't expand on purpose!
– Tim
Nov 25, 2020 at 7:56
• Harmonics can also be used for tuning. For most of the strings, the 5th fret harmonic on the lower string is the identical note to the 7th fret harmonic on the one above. (4th and 5th fret for the G-B step). Nov 25, 2020 at 12:52
• To continue, there are two places you can produce the 1/3 harmonic, two the 1/4 (because the "third" place will produce the 1/2 harmonic), and so on. Nov 25, 2020 at 15:24
• Very true. Any node will do it.
– user50691
Nov 25, 2020 at 16:12

It's all down to harmonics. By touching (gently) the string being plucked exactly half way along its speaking length, it produces a note an octave higher.

You can sample this by touching an open string above its 12th fretwire. Then play that string.The note will come out an octave higher. Two hands will help initially, but this guy is using a finger to touch, and another to play. That's because his other hand is occupied fretting the note concerned. Watch how each note played is touched at its halfway point.