Harmonics?

Ok, this is going to sound pretty stupid, but...

What exactly are, harmonics?

I mean, I've never seen an exact definition of what they are, and maybe I might alreaady know but not know the name, or whatever...

I'd simply like a simple explanation of what they are. If anyone is willing to, of course.

Ah wonderful Wiki :)

Harmonic - Wikipedia, the free encyclopedia

hope it helps :P

As a summarised definition, a harmonic is an overtone produced when a stringed instrument is plucked at a "node point". In plain English, it means that on a guitar, for example, the player can use the fretting hand to lightly touch a string at a certain point, which will produce a clear, bell-like sound. This is a harmonic.

Here is a link to a quick instructional recording for your (un)enjoyment, thrown together with the help of my electric guitar.( I apologise for the poor sound; harmonics have a very different sound when subjected to distortion.) The first note is an ordinary fretted one, but this is followed by a series of random harmonics. After that, there's a tune you might recognise, first played solely with harmonics and next without.

Maybe I should have tuned my guitar before I recorded.

It's worth mentioning that brass instruments ('cept the sax) depend entirely on using the "harmonic series". The basic tube gives a set of notes corresponding to the series, then by adding extra lengths of tube (using the valves) the fundamental can progressively be lowered, bringing a new set of notes into play.

Woodwinds rely on harmonics to 'overblow' their octaves (and higher) - in the case of the clarinet, at the 12th. (Being a cylindrical bore, the clarinet sounds no even-numbered harmonics for practical purposes).

Some oboe pieces have notes with the 'harmonics' sign noted above them (little circle like a degree sign), applying from f#-c at the top of the treble clef - these notes are normally played on the 2nd harmonic (octave) but they can also be played at the third (a 12th) - like G would be fingered as a low C but vented at the 12th. Timbre is different.

The oboe is a complex acoustic system, the harmonic richness is why multiphonics are fairly easy. The clarinet can produce a few chords too. (Not sure about flute and bassoon).