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Artificial Harmonics

You know those "diamond head" notes? In an orchestral Score I saw it on the string instruments. What does it mean?

Oh... Any of you play a string instrument such as Violin, Viola, Cello or Double Bass? Perhaps you people can give a better answer to my question.
.

Re: Artificial Harmonics

Reply #1 –
Those are, as your heading indicates, harmonics. A string vibrates not only as a whole, but as two halves, three thirds, four fourths, etc. - all simultaneously. By touching it at the right points, you can isolate these "upper partials" or "upper harmonics" of the string and cause them to sound instead of the string's fundamental note. "Natural harmonics" are those made on an unstopped string; "artificial harmonics" are made on a string that's been stopped by another finger. String players usually make artificial harmonics by placing the first finger down and then touching the string with the fourth finger at a place one/fourth of the way between the stopped note and the bridge. This produces a harmonic two octaves above the stopped note. It has a very pure, ethereal sound, without vibrato.

Harmonics can be used on any stringed instrument. Guitar and harp harmonics are especially beautiful - they sound like distant ringing bells. Guitarists also commonly use harmonics to tune, as the first harmonic on one string is the same pitch as the second harmonic of the string directly below, allowing the two strings to be tuned to a unison (much easier to hear than a fourth). This works for all strings except between B and G.

Probably a lot more than you wanted to know....

Cheers,

Bill

Re: Artificial Harmonics

Reply #2 –
Quote from: William Ashworth –
Probably a lot more than you wanted to know....

Actually Bill, you are quite wrong (for me) - previous explanations of this have just been "it's a requirement to play the harmonic note" or "it's the harmonic note two octaves higher than written". 
I was going to answer Kristopher in a like way - but decided not to in case someone else with better knowledge answered - and you did.

Thanks from me - I'm glad to have the additional information.

Rich.

Re: Artificial Harmonics

Reply #3 –
William Ashworth's reply was quite correct.  The only thing to add is the point(s) on a string that don't vibrate at certain harmonics where you can touch the string to create them is/are called (a) nodes.
Since 1998

Re: Artificial Harmonics

Reply #4 –
I would venture to say that not only is the pitch different (typically 1 or 2 octaves higher as the other comments describe) and not only vibrato-less by necessity, but also a different timbre, with few partials left, since stopping the string by touching it at a node (integral fraction of the string length free to vibrate) blocks off any partials lower than itself and typically leaves only residual amplititude of partials higher than itself.  The waveform comes close to being a pure sine wave on guitar, probably closer to a sawtooth wave with somewhat rounded peaks on a bowed string stopped by touching a node.

Re: Artificial Harmonics

Reply #5 –
Ahh...! Now I understand about those notes now but does it affect the sound of the string instrument? William, You once said about the harmonic playing two octaves higher, right?

This gives me another question to ask: "sul ponticello". Does it mean play near the bridge of the string instrument or play some octave higher? How does this relate to Artificial Harmonics?

Re: Artificial Harmonics

Reply #6 –
"Sul ponticello" means to play near the bridge. It has no relationship whatever to artificial harmonics except that both are specialized techniques for playing stringed instruments. The sound of sul ponticello is thin and brittle, unlike harmonics, which are clear and ringing. The only thing the sounds have in common is that they both tend to be soft.

Playing in harmonics does change the pitch (sul ponticello doesn't). Maybe a little more explanation is in order.

When you hear most instruments (the flute is an exception), you are actually hearing a composite tone. You are hearing the basic pitch the instrumentalist is playing, but you are also hearing higher notes. These notes are caused by the string (or the air column, in a wind instrument) vibrating in sections as well as in the whole. Since pitch is determined by the length of the vibrating body, the sections that are vibrating separately produce higher pitches than the sounding body as a whole. The two halves of the string produce tones an octave above the basic pitch (the "fundamental"); this is called the "first harmonic" (or "first partial," or "first overtone"). Similarly, each third of the string produces tones an octave and a fifth higher than the fundamental (the "second harmonic"); each fourth of the string produces tones two octaves higher ("third harmonic"); and so on. The characteristic sound of each instrument (its "timbre") is caused by the particular pattern in which it emphasizes the different harmonics: a clarinet, for example, emphasizes the fundamental and the second harmonic, with most of the others at least present up to about the fifth harmonic (two octaves and a fifth above the fundamental). Flutes emphasize the fundamental so strongly that the others are hardly there at all, which is why they sound so pure.

OK. Now: when you touch a string in the middle, you prevent it from vibrating as a whole. So the fundamental disappears, and the lowest tone you hear will be the first harmonic - an octave above the fundamental. Similarly with the other points where you can touch the string to produce harmonics. Touching it a fourth of the way along prevents anything lower than the third partial from sounding, so the lowest pitch you hear is two octaves above the string's open sound. Warren mentioned that the points where the string is touched are called "nodes." They are called that because the lines of vibration come together there, so that point is standing still. You can actually see this if you look at a string vibrating at a harmonic interval. (You don't have to keep touching the string, by the way: once you have lifted your bow, or stopped plucking, you can and should lift the finger off the node. The string will keep vibrating in the pattern of harmonics that has been set up.)

(Incidentally, overblowing a wind instrument does the same thing as touching a string partway along: it causes the air column to vibrate in sections. This is how winds get into the higher octaves.)

As Milton suggests, the timbre changes when you remove the fundamental; it becomes less complex, which is why harmonics are typically thought of as "bell-like" (they are really flute-like, but never mind). When a string player is playing sul ponticello, he or she is actually making the sound more complex, instead - because the string is being activated close to its end, thereby emphasizing the higher partials, which are produced by the shorter sections of the string. So sul ponticello is "scratchy" and artificial harmonics are "bell-like."

.....and that's quite enough acoustics theory for one night. Hope this has helped....

Cheers,

Bill

Re: Artificial Harmonics

Reply #7 –
Ahem...
Verbatim "sul ponticello" means "on the bridge", but of course you can not play exactly on it. :-)

Moving the excitation position (either bowing, picking, plucking, hammering...) along the instrument resonant (standing) wave changes the sound of the instrument because you change the "filtering" effect of the instrument. This alters the proportions of the partials.
Some instruments are more sensitive to this.

For example, in the piano the hammering is typically done in the best place to reduce the 7th harmonic that's notoriously out of tune and not very pleasing.
In the harp, unless I use the nails, the difference is minimal.
In the violin there is precisely the "sul ponticello" playing mode.
...

Re: Artificial Harmonics

Reply #8 –
You might want to check out the attachment in this tip.  All of the notes at new tempos are the appropriate harmonic from the first C below the bass staff.
Since 1998

Re: Artificial Harmonics

Reply #9 –
Quote
clarinet, for example, emphasizes the fundamental and the second harmonic, with most of the others at least present up to about the fifth harmonic

Bill,
the clarinet has a sound reminiscent of a square wave, indeed that's how it's synthetized with "subtractive" synthesys (analog synts), and a perfect square wave contains only odd harmonics.
Of course the clarinet sound is not a perfect square wave so a small quote of even harmonics are present, but the second one is almost non existent.

For example see:
http://209.85.135.104/search?q=cache:UVELiffYz6wJ:www.phys.unsw.edu.au/music/clarinet/E3.html+clarinet+sound+spectrum&hl=en&ct=clnk&cd=1&gl=it

Cheers
Maurizio

Re: Artificial Harmonics

Reply #10 –
All of what you say is accurate, Maurizio....but a little complicated for a beginner....

You are correct about the actual meaning of the Italian, as of course you would be. However, as you also note, for a string player sul ponticello doesn't actually mean on the bridge - though there is the occasional modern score that calls for that.

Thanks for clarifying the clarinet timbre. I wrote that post late at night and was trying to simplify, and in the process I forgot about the lack of all odd-numbered partials in the instrument.  As to the harp - the timbre certainly doesn't change very much. But I do notice that the sound is purer when plucked in the center - near the center node, where you normally make artificial harmonics (to get back to the original topic) - than it is when plucked near either the bridge or the soundboard. Plucking near the ends of the string produces a dulling of the sound, which I have always attributed to a greater excitation of the higher harmonics and a corresponding drop in intensity of the fundamental, though I could be wrong. This is true, anyway, of the Celtic harp. I don't play concert harp, so I can't judge.

Anyway - fascinating topic. I'm surprised we haven't heard from brass players yet; they are more familiar with the upper reaches of the harmonic series than anyone else.

Cheers,

Bill

Re: Artificial Harmonics

Reply #11 –
Hey Bill,
it's me that must thank you for all your detailed explications.
I simply tried to adjust the small imperfections... trying not to add some myself.

Quote
Plucking near the ends of the string produces a dulling of the sound, which I have always attributed to a greater excitation of the higher harmonics and a corresponding drop in intensity of the fundamental, though I could be wrong.

You're perfectly right.
If you pluck the string in the middle point you're exciting the string in the only anti-node of the fundamental so you have the highest relative level of the fundamental.

Quote
I don't play concert harp, so I can't judge.

Nor do I. You know: $$$$$$$!
Only "celtic" harp with gut strings.
My daughter sometimes lowers only partially some levers to get what she calls "sitar" sound.

About unusual ways to play strings, nobody wrote about the "col legno" ("with the wood": using the wooden part of the bow) or "con sordina" ("with mute").
The latter I used very often while practicing violin to save my neighbours' ears...

Even more off topic is Rossini's ouverture from "Il signor Bruschino" in which the second violins are instructed to tap the bow on the music stand.
Then there is Ethan Winer's "A Cello Rondo"... :-))))
http://www.ethanwiner.com/video/index.html

But all these things are explicitly written on staff or, at most, abbreviated ("con sord." etc.) so there are no odd symbols to learn or add to NWC. ;-)

Cheers
Maurizio

Re: Artificial Harmonics

Reply #12 –
Quote from: William Ashworth –
Anyway - fascinating topic. I'm surprised we haven't heard from brass players yet; they are more familiar with the upper reaches of the harmonic series than anyone else.

True, but our interest is somewhat differently founded than the string players...

For the string player harmonics are an effect, for us they are the basis of our playing.  Yet the beginning brass player is taught nothing about it other than increasing the tension in the lips to raise the pitch of the notes we can play on the valves/slide.

However, if you want to hear the change in timbre caused by the loss of harmonics as we go up the harmonic series consider the bass trombone.  In its lowest register the sound is full and gutsy.  Lots of power.  Take the same instrument up a few partials (harmonics) into the middle of it range and the sound becomes sweeter and more lyrical, push up a bit further and you start becoming more flute like, the sound thins out and seems somehow purer.

Or consider high trumpet players like Maynard Ferguson (RIP).  They get so high they no longer need valves to provide the different notes 'cos the harmonics they are using are so close together the instrument no longer "slots"*.  The sound is more whistle like than trumpet like...

*When a brass instrument "slots" it is "settling" into the harmonic.  Increase the tension in the lips, maybe add some air velocity, the horn naturally sounds the next harmonic.  The better the horn, the more closely the slot is in tune.  The very best horns allow you to "move" around the slot on your lips making lip trills and rises and falls easier while not losing the natural feel of finding the harmonic you're wanting to use.  Easier to do than to describe...

I've talked rather more fully on the relationships of the harmonic series in a recent post on glissando: https://forum.noteworthycomposer.com/?topic=6552.msg44697#msg44697
I plays 'Bones, crumpets, coronets, floosgals, youfonymums 'n tubies.

Re: Artificial Harmonics

Reply #13 –
And of course the "opposite" of sul ponticello is sul tasto which means over or near the fingerboard, applying equally to bowed strings and guitar.  There is one way to play literally "on the bridge", but only in France, and only while standing sur la pont d'Avigon!  ;)

Re: Artificial Harmonics

Reply #14 –
Lot's of very good answers, but can you apply an artificial harmonic to every instrument? Like a Tuba or a Trombone or even a bassoon?

Re: Artificial Harmonics

Reply #15 –
G'day Kristopher,
I notice from your profile that you're 13, so rather than hand you all the answers on a platter I thought I'd ask you what you think.

You've read the responses.  As a result you should have some good information to add to what you already understand.  So, having a better insight in how at least some instruments function what do you think?

What kind of instruments lend themselves to artificial harmonics?  What kind do not?  Why?  Are the answers absolute or is there some "grey"?

Think about how you might cause the harmonics to occur.
I plays 'Bones, crumpets, coronets, floosgals, youfonymums 'n tubies.

Re: Artificial Harmonics

Reply #16 –
Okay Lawrie. The reason why I ask wether or not other instruments are able to play artificial harmonics is because I play the flute and IF I played a G or other notes (just basically blowing it flawlessly) I get nothing but just a column of air with no nice flute sound, So by just playing a brass instrument flawlessly you may get nothing but a strange sound, correct? :-)  I'm basically asking wether or not artificial harmonics can create different sounds or effects to an instrument.



You're Right, Lawrie, I should start putting in what I understand FIRST and then receive the real answers from others.

Re: Artificial Harmonics

Reply #17 –
G'day Kristopher,
Quote from: Kristopher –
(just basically blowing it flawlessly)

What do you mean by this?  Are talking about fingering a note and blowing into the mouthpiece instead of across it?

In any instrument you must create a vibration of some kind in order to transmit energy.  This energy transmission we call sound.  In the case of your flute, if you don't create a vibration in the air column at an audible frequency there will be no sound.  The physics of having a vibrating air column will naturally result in harmonics (multiples of the fundamental).  The number of, order and energy in each harmonic will affect the timbre of the sound.

IIRC a flute has few energetic harmonics thus the sound is "pure".  I.E. close to a pure sine wave.  OTOH a brass instrument is rich in energetic harmonics and thus the characteristic brass sound.

So again, with which instruments can you create artificial harmonics.  It will already have natural ones...
I plays 'Bones, crumpets, coronets, floosgals, youfonymums 'n tubies.

Re: Artificial Harmonics

Reply #18 –
I'm totally confuse about all this! I'm like lost in a maze or something. But don't get confuse too... There are times where one doesn't know what the other is talking about. But I now I understand about the topic.

You're a kind person...

Re: Artificial Harmonics

Reply #19 –
G'day Kristopher,
don't be confused, just break the things down into little pieces that you can understand.  Then think about how those pieces relate to build up the bigger picture.

You asked about which instruments can have artificial harmonics?  Obviously stringed ones can and you know this because you referenced it in your initial post.  So, finger a note and touch the string at a node point and voila an artificial harmonic.

What is this actually doing?  Think about it.  By fingering the note you are setting the fundamental frequency but by touching the string on a node point as well you are preventing the string from vibrating at any frequency that doesn't have a node at that point.

So, if you touch the string a quarter of its length from the point where you set the length with the fingering you will stop the fundamental (1st harmonic), the second harmonic and the third harmonic from sounding.  The 4th harmonic will sound.  What about the 5th, 6th 7th and 8th?

I'll let you off the hook, the 8th harmonic will also sound because it also has a node at that point.  The 5th, 6th and 7th do not so they will be damped (not sound).

So, armed with this information, what other types of instrument can you think of that you might be able to do some equivalent thing too?
I plays 'Bones, crumpets, coronets, floosgals, youfonymums 'n tubies.