Science of a Harmonic?

[Misanthrope189]

Hey,
I was just thinking about artificial, and natural harmonics. I know how they're created, but does anyone know the science of why, when you pick the note, and immediately mute it with your finger, it squeals like that? I envision all the energy created by stressing the string with the pick wanting to be released into the tone, but when you immediately mute the string, the lost harmonic just kinda rings out...kinda like if you're revving a good engine, and you're around 6 thousand or more rpms, and you floor it for a second, and then immediately get off the pedal, the engine kinda goes vrrrrmmmmmmmmm eeeeeeeeemmmmmmmm! and sorta makes a noise like that...where it was just given all that energy and then released...sorry for the bad analogy.

Science of harmonics?

Cheers,
Nick

[LesPaulCustom]

Re: Science of a Harmonic?

The point on a string at which a harmonic is/can be produced is called a node.

This is basically where the string has no vibration due to the elipitical arc created by the string as it is moved.

This is how I understand it anyway [img]images/icons/grin.gif[/img]

[Hotrodder]

Re: Science of a Harmonic?

Real basic answer here.

When you strike a string to make it vibrate it does not vibrate in just one wave length pattern, it vibrates in many patterns. Now if you hold you finger above say the 7th fret it stops all the vibrations except for one, that is the harmonic you hear.

In the below very bad picture lets say A is the 7th fret so when you place your finger there you stop the blue wave but not the red wave so you hear a harmonic.

[Ninja Guitar]

Re: Science of a Harmonic?

BTW, any 4th fret harmonics or artificial harmonics produced at the 4th fret of the note being fretted is always slightly flat. I learned that from my trumpet playing days, cause there are a few certain notes in a perticular harmonic range that naturally are a little flat.

[Ace]

Re: Science of a Harmonic?

OK, here is the way I understand it. A string vibrates at a certain frequency, given it's tension and length. For example, let's say you are playing a note that is at 220Hz, or cycles per second. When you place your finger in the middle of the vibrating string, say the twelveth fret of the open string, you cut the vibrating length in half, giving you a note twice as high in pitch. That is why when you play the harmonic at the twelveth fret and fret the note, they are both one octave higher than the open string. Remember when you go up an octave you double the frequency. Likewise when you interupt the strings vibration someplace else in it's length, you get different pitch changes, like at the 7th fret you jump two octaves, and so on. The more even the number you divide by, the easier it is to get the harmonic, that's why the 12th fret harmonic is easy and the 1st fret is hard. Hope this helps...

[Newc]

Re: Science of a Harmonic?

Here's the simple answer:

When you pinch the note to create a pinch harmonic, you are greatly shortening the oscillation of the string, thus greatly increasing the sounded pitch of the note to the point that it becomes a harmonic.
This is also why a fretted note that is pinched at the body (when picking) will have different pitches when you pick along the string in different places (ala Billy Gibbons).

Newc