Andreas Preuss

How important is the overtone range to the sound of a violin?

Recommended Posts

Since a few days now I am trying to put in words what is going around in my head. And no matter how I try to formulate it, it looks like half missing the point. 

Anyway.

So, what do overtones do to the sound? 

Are overtones the only important factor for the so called projection? 

Or is it rather a certain 'mixture' of overtones which makes the sound stick out? 

And then how does it relate to details in the making process? 

Comoaring instruments with Strad arching to instruments with Stainer arching makes clear that arching shape has a fundamental influence on the the timbre.

.Second there is the string angle which regulates the vertical force on the top. However does a smaller angle (less than 180) make more overtones? Or eventually overtones in the wrong frequency range?

Then, maybe the material itself. If we would use another material the violin wouldn't sound the same.

Share this post


Link to post
Share on other sites

Overtones are very important for coloration, completeness, and presence of tone.

This is also part of the players technique.  Overtones change with bowing tech, and give the difference between bright, brassy, brilliant, flutey, rich, warm, etc.

Also, these help us hear and project articulations.

Share this post


Link to post
Share on other sites

I think Don did an experiment with string angle over the bridge. From what I remember, only extremes made a discernable difference. 

Share this post


Link to post
Share on other sites

'String angles' doesn't equal 'overtones'

However, slightly more tension in a system will tend to send more energy into higher frquency vibrations.  But there are many factors.  Balance is the aim.  We want a result that puts the player in a good position to take the sound anywhere desired.

Share this post


Link to post
Share on other sites

If overtones are defined as sound vibrational energy emitted at frequencies greater than the fundamental frequency

of the note being discussed then most of the sound of the violin is composed of overtones.

So I would say overtones are all important to the sound of the violin.

The lower notes on the g string are known to have almost no energy at the fundamental frequency and

are hence literally nothing but overtones.

Share this post


Link to post
Share on other sites
1 hour ago, donbarzino said:

If overtones are defined as sound vibrational energy emitted at frequencies greater than the fundamental frequency

of the note being discussed then most of the sound of the violin is composed of overtones.

So I would say overtones are all important to the sound of the violin.

The lower notes on the g string are known to have almost no energy at the fundamental frequency and

are hence literally nothing but overtones.

From what I've heard, the G string's fundamental isn't even heard anyways. 

Share this post


Link to post
Share on other sites
14 minutes ago, Andreas Preuss said:

All frequencies above 3000Hz

That's not the correct definition of "overtones".  Nevertheless it is an interesting question: What is the importance of sound output over 3000Hz?

Share this post


Link to post
Share on other sites

Are not overtones the harmonics that are produced from a fundamental note? We talk about the pure sound of a Strad but most of us have never had the first hand experience. It seems that the harsh metalic and sometimes "loud" sound is produced in the 2,000-3,500 Hz range where the human ear is very good at hearing sound.  Also, it appears that some of the harmonics for each note are not pleasing to the ear and produce a disonant sound with the rest of the harmonics. It is like playing a cord with a bad note included. The overall energy output from the violin is not that great, and yet it can be heard above the entire orchestra. Why? Because the energy produced by the harmonics in the upper range is stronger and can be heard above the entire orchestra. The human ear fills in the fundemental note if needed as is seen by the G string note which actually has a weak level when compared to the second harmonic. I have wondered if it would be better to understand why cheap violins sound so bad and then eliminate the cause of the bad sound. All of this is part of the process of understanding what makes a good violin. 

Share this post


Link to post
Share on other sites

"Sympathetic tones" might be a better description of what happens.  You introduce a forcing signal when you draw the bow.  This vibration induces a wide range of responses from the strings and mechanical structure of the violin.  This response is heavily influenced by both construction and technique.  Taken together these effects produce a "chorus" that is perceived as color and projection.  Understanding what we like in a chorus is a very good question.

Share this post


Link to post
Share on other sites

It's a little complicated because several different things give the same appearance to our ears, and these things interact in our experience of sound.  And some of what's important is not intuitive and a bit mathematical.

1) a physical resonance at a frequency will tend to also resonant at integer multiples of the frequency.  So a string has a very 'high q' fundamental resonance.  The frequency of this resonance is related to the time it takes a disturbance of the string to shoot up and down its length.  But if stimulated by white random energy, the string will end up resonating not just at the fundamental frequency, but at a number of integer multiples of the frequency also.  These are called partials, overtones, or harmonics.  

2) Sound only actually travels through the air as fluctuating air presure. And all the sounds present add together at once to fluctuate the presure in sometimes very complicated ways.  The complication is that this adding together can obscure information about the original sound source.  Just as 2+2 and 1+3 both add to 4, different original sound sources can add to the same complicated fluctuation of air presure.  So here comes the not so intuitive math part.  A simple sine wave flucuation of air presure is what you get if you sound just the fundamental of something.  And any smooth sine wave fluctuation of air presure will appear to us as pure simple pitch with its frequency based on the time it takes for that sine wave to comple one cylce.  Any more complicated periodic fluctuations of presure will still be sound to us, with its fundamental based on the time the complicated presure wave takes to complete a full cycle.  However, such a sound will seem to us like a fundamental combined with overtones. 

There is a strange mathematical result behind this. It turns out that any complicated periodic wave can be duplicated by adding together the right balance of a fundamental and its harmonics.

3) We can't readily hear certain differences. If we take 5 different pitches that are interger multiples of a fundamental, and then use ideal sine wave generators to play some balance of these together in perfect phase, then these will add together in the air and fluctuate the presure in a particular way.  And if take an ideal speaker, it could create this same flucuation in the air directly in one motion, rather than by combining the separate motions.  If all was done ideally, we wouldn't be able to distinguish the two ways of generating the same flucuations. 

*********

The last bit is that our ear more or less dissects complicated sounds into a combination of simple sounds.  These won't neccesarily be in an ideal harmonic series.  Instead, these will be the simplest collection of pure tones the ear could extract to add up to the total sound heard.  The ear then has to try and understand how these components go together.  Are they all from one sound, or from several?

If the patern of simple sounds form a good harmonic series (that is they fall into simple integer multiples), then the brain will tend to put those simple sounds back together as partials of that harmonic series, and the fundamental of that series will tend to be 'heard', even if it isn't physically present.  So the ear splits sounds in components, then puts them back into an impression of tone if they're harmonically related. 

But the ear also tends to recognize the relatedness of component sounds even when they aren't ideally harmonic.  Many real physical systems tend to create overtones above a fundamental that are somewhat distorted from the ideal harmonics. You can hear this for example in the overtones of an old oxidized piano string, and many other situations. 

Also, as you go higher and higher in an ideal harmonic series, the paritals get close together, in fact, in each octave above a fundamental the partials get twice as dense.  So you go up a few octaves and the partials are micro tonally placed. 

So now we've some distinctions in the terms. While casually interchangeable, we can say harmonics more refer to the ideal interger multiple frequencies above a fundamental, and overtones more refers to the actual component tones over the fundamental of a real sound. 

**********

We can see that many things add to the ear's challenge in identifying overtones.

The ear likes to recognize the 'relatedness' and 'not relatedness' of the overtones it hears.  If there is a lot of high frequency content that the ear can identify, that's pleasing and 'harmonious'.  I there's a lot of high frquency it can't identify, that's brash or ugly.  If there isn't a lot of high frequencies, that's dull.

 

Share this post


Link to post
Share on other sites
20 hours ago, David Beard said:

'String angles' doesn't equal 'overtones'

However, slightly more tension in a system will tend to send more energy into higher frquency vibrations.  But there are many factors.  Balance is the aim.  We want a result that puts the player in a good position to take the sound anywhere desired.

Thinking about extreme string angles we can see how it changes, I think. Nobody would set up an instrument with a 180 degree string angle because it wouldn't sound. 

On the other hand there was a period in French violin making where most violins had a very low neck overstand resulting in a smaller angle at the bridge. Most of those instruments seem to have a nasal sound. But in the end 'nasal' is just a product of how overtones are composed,

Balance is an interesting thought. But without knowing what to balance against what else it looks rather like walking in the dark to me. 

 

Share this post


Link to post
Share on other sites
2 hours ago, Marty Kasprzyk said:

That's not the correct definition of "overtones".  Nevertheless it is an interesting question: What is the importance of sound output over 3000Hz?

Anything above the fundamental note is defined as overtone. But it seems that our ears are most sensitive to overtones in the range above 3000 Hz.

Share this post


Link to post
Share on other sites
17 minutes ago, Andreas Preuss said:

Anything above the fundamental note is defined as overtone. But it seems that our ears are most sensitive to overtones in the range above 3000 Hz.

An overtone is a note above the fundamental but in its harmonic series, and it is usually heard along with  the fundamental (other than cases like harmonics, where the fundamental is damped in order for the overtone to be heard alone), so it’s more like a secondary tone to the fundamental.

Another example besides that of a vibrating string is the art of throat singing. The singer makes a fundamental sound from the throat or back of the mouth, and by modulating the shape of the middle and front of the mouth, a diverse palate of overtones can be emphasized. Really good Tuvan singers can excite multiple overtones at once. 

Share this post


Link to post
Share on other sites
1 hour ago, Andreas Preuss said:

 

i was sometimes wondering if not a pinch of disharmonic overtones creates the distinctive 'sizzle' in good sounding instruments.

i wonder if there was any research done on this.

Due to the way bowed strings work, all overtones are absolute harmonics of the fundamental.  Excepting if the bowing is such that something other than the usual Helmholtz motion happens.  And there can be other minor things like white noise from string friction as it slips, and torsional movement.

At the higher frequency overtones, it's really hard to hear what note the overtone is, and sounds more like sizzle or jangle, or perhaps a sharpness to the edges of the other parts of the note.

If you want to find out how important overtones are (whatever frequency you happen to think is important), try equalizing out that frequency range from a solo violin recording.  It's extremely easy to do.

Share this post


Link to post
Share on other sites

For what it is worth I think that the overtone range means everything to the sound of a violin. 

For many years I thought the analogies of string instruments to the human voice were a little over the top 

but if you listen carefully to Maria Callus  you can hear she has a texture to her sound that is exceptional.  I would call these  overtones.And I know that certain instruments have similar sounds that really make the  mark . These sounds really do hit the spot and certain instruments can reproduce this sound.

Share this post


Link to post
Share on other sites
8 hours ago, Don Noon said:

Due to the way bowed strings work, all overtones are absolute harmonics of the fundamental.  Excepting if the bowing is such that something other than the usual Helmholtz motion happens.  And there can be other minor things like white noise from string friction as it slips, and torsional movement.

At the higher frequency overtones, it's really hard to hear what note the overtone is, and sounds more like sizzle or jangle, or perhaps a sharpness to the edges of the other parts of the note.

If you want to find out how important overtones are (whatever frequency you happen to think is important), try equalizing out that frequency range from a solo violin recording.  It's extremely easy to do.

I have done that. 

But speaking of filters, wouldn't it be more logical to think of the violin body as a filter rather than an amplifier for certain frequency bands? 

On the very high end of overtones we get to notes which don't belong to the scale of the base note or not?

Share this post


Link to post
Share on other sites
1 hour ago, Andreas Preuss said:

IBut speaking of filters, wouldn't it be more logical to think of the violin body as a filter rather than an amplifier for certain frequency bands? 

On the very high end of overtones we get to notes which don't belong to the scale of the base note or not?

The violin body is not an amplifier, and mostly not a filter either... it's a transducer, converting string vibration energy into sound energy.  Some frequencies transduce well, others not so much.

Yes, in the higher frequencies, overtones tend to deviate from "notes" as we define them... but only because of our 12-note scale, which has compromises in frequency.  The string overtones are still exact harmonics of the base frequency.

Share this post


Link to post
Share on other sites

I know that the textbooks tell us that a bowed string is harmonic. But have accurate measurements over a wide range of fundamental frequencies ever been made in order to confirm exact harmonicity? 

Share this post


Link to post
Share on other sites
5 minutes ago, JohnCockburn said:

I know that the textbooks tell us that a bowed string is harmonic. But have accurate measurements over a wide range of fundamental frequencies ever been made in order to confirm exact harmonicity? 

I guess that is a question which should be directed to Fan Tao of D'Addario.

In any case it seems that certain strings enhance a certain overtone range more than others the reason for which one string might work well on one violin but not on another.

Share this post


Link to post
Share on other sites

The "inharmonic" content seems to come from two things -- the fact that a string isn't an "ideal" string, and the method by which the string is excited.  An interesting question might be Is a "pure sound" in violin speak the one that's the least inharmonic?  Maybe, because a pure sound seems to come from the least pressing that will still excite the string sufficiently, which might translate to less interference from the bow and therefore more of an ideal string motion.  A good experiment that probably actually hasn't been done would be to record the purest violin sounds you can find and maybe just the most interesting you can find, and then compare the inharmonic content there to what you see in less striking violins/playing.  Is less more?  Four shots from a 44?

Share this post


Link to post
Share on other sites

Before you all start thinking about harmonicity and how to put it in or take it out I suggest you take a look at the actual frequencies of the harmonic sequence compared to the notes of the musical scale. Because I suspect you are making assumptions that are incorrect.

Hint: on trumpet, which is a theoretically harmonic instrument,  there are fingerings up only to the 7th harmonic (4th octave), after which the fingering chart turns to finding the closest harmonic to the real note you want, and then bending the harmonic pitch over to the nearest real note. Past a certain point,  there's not precise correspondence between harmonics and the notes of our scale except at octaves of the fundamental. That is, the higher harmonics are all, by the incorrect definition being used in this thread, "inharmonic"--out of tune with the musical scale.

One reason that older instruments may be considered more beautiful in tone quality is because their output drops rapidly at a much earlier point (as measured in Hertz) than modern ones, and the truncation cuts out many more of those out-of-tune harmonics.

(You can't believe your FFT program: most or all of them display theoretical frequencies, calculated, rather than frequencies as measured, for the higher harmonics according to the developer of one computer program for pianists with whom I had this discussion. From various sources I gather that FFT programs aren't designed to extract the kind of detailed information we hope that they extract, and do a lot of averaging and interpolating)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.