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#2223114 - 01/30/14 12:15 PM Re: Simultaneous partials in a string: reality or myth? [Re: DoelKees]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: DoelKees

OK, then, I'll say some more stuff, but I get the feeling I already said it. The motion of the "ideal string" taught in high-school can be completely described as the sum of in infinite number of harmonic vibration modes. The motion of a real string can not. A piano is more than a single string and is quite complicated. Partial analysis is a useful approximation but... etc. as I posted already.

Kees


Well stated. This argument is getting stale.

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#2223145 - 01/30/14 12:59 PM Re: Simultaneous partials in a string: reality or myth? [Re: pyropaul]
UnrightTooner Offline
4000 Post Club Member

Registered: 11/13/08
Posts: 4914
Loc: Bradford County, PA
Originally Posted By: pyropaul
Originally Posted By: UnrightTooner


It is an easy thing to create an electronic square wave generator, and there is no need to superimpose an infinite number of sine waves at exact intregal frequencies (partials) and at exactly the same amplitude to do so.

Do you see my point?


I do see your point, but it doesn't mean that the electronic square wave is not composed of partials. All of analog electronic communications uses this fact, whether you believe it or not.

.....


Hmmm... if I take a log and cut it and split it into cord wood, does that mean the log was always made of cord wood?
_________________________
Jeff Deutschle
Part-Time Tuner
Who taught the first chicken how to peck?

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#2223154 - 01/30/14 01:19 PM Re: Simultaneous partials in a string: reality or myth? [Re: UnrightTooner]
pyropaul Offline
Full Member

Registered: 11/16/10
Posts: 174
Loc: Montreal
Originally Posted By: UnrightTooner
Originally Posted By: pyropaul
Originally Posted By: UnrightTooner


It is an easy thing to create an electronic square wave generator, and there is no need to superimpose an infinite number of sine waves at exact intregal frequencies (partials) and at exactly the same amplitude to do so.

Do you see my point?


I do see your point, but it doesn't mean that the electronic square wave is not composed of partials. All of analog electronic communications uses this fact, whether you believe it or not.

.....


Hmmm... if I take a log and cut it and split it into cord wood, does that mean the log was always made of cord wood?


No, it was made of quarks. You just didn't divide into fundamental units.

Why do you think computers emit radio frequency interference? Part of the reason is that their square wave clocks emit harmonics that are in that part of the spectrum. Anyway as Prout said, this is getting stale. I'm an electronic engineer by trade so I just use this stuff quietly, irrespective of whether others believe it or not.

Paul.


Edited by pyropaul (01/30/14 01:20 PM)

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#2223163 - 01/30/14 01:31 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
UnrightTooner Offline
4000 Post Club Member

Registered: 11/13/08
Posts: 4914
Loc: Bradford County, PA
Paul:

In a former life I had an FCC technician license. smile
_________________________
Jeff Deutschle
Part-Time Tuner
Who taught the first chicken how to peck?

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#2223228 - 01/30/14 03:41 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
Mark R. Offline
1000 Post Club Member

Registered: 07/31/09
Posts: 1960
Loc: Pretoria, South Africa
Well, now suddenly Kees submits the argument that a piano has multiple strings...

But still, nobody as yet has shown where the "approximation" of partial analysis falls short in a real string, nor has anyone shown that real partials (modes) cannot co-exist in a real string.

Until such time, I'll stick with the understanding that a real, vibrating string does contain partials, and that the string's motion is exactly the sum of those partials. They might be damped at different rates, they might be bounded by one slightly non-rigid termination of varying impedance, etc.etc., but together they still constitute the whole motion. (What else would the motion be made up of, if not its constituents?)

This understanding certainly seems to be good enough for tuning the dang thing, even for Kees doing his spectrograms on it.

Many fascinating responses to my opening post, I thank you all.
_________________________
Autodidact interested in piano technology.

1922 49" Zimmermann, project piano.
1970 44" Ibach, daily music maker.

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#2223231 - 01/30/14 03:48 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.


http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

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#2223235 - 01/30/14 04:03 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1701
Loc: Vancouver, Canada
[quote=Mark R.
But still, nobody as yet has shown where the "approximation" of partial analysis falls short in a real string,/quote]
I did show that (subtract partials and see), noone reads what I write it seems.

Kees

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#2223251 - 01/30/14 05:02 PM Re: Simultaneous partials in a string: reality or myth? [Re: prout]
Withindale Offline
1000 Post Club Member

Registered: 02/09/11
Posts: 1936
Loc: Suffolk, England
Originally Posted By: prout
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.

http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

Well worth the effort of wading through the math.... or reading about the results of the simulations, e.g:

Observations made on real signals show that the pressure and soundboard motion spectra, including the bridge, have a denser and richer content than the strings. The simulations help here to understand these differences and identify the additional spectral components.

QED.


Edited by Withindale (01/30/14 06:41 PM)
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

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#2223257 - 01/30/14 05:19 PM Re: Simultaneous partials in a string: reality or myth? [Re: Withindale]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: Withindale
Originally Posted By: prout
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.

http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

... or read about the results of the simulations, e.g:

Observations made on real signals show that the pressure and soundboard motion spectra, including the bridge, have a denser and richer content than the strings. The simulations help here to understand these differences and identify the additional spectral components.

QED.

Sorry Ian, I don't get your point. I am, at the moment, training in a flight simulator, something I have to do every six months for a week. When I completed my initial training on this particular jet, I did my first flight in the real airplane with a full load of paying passengers. I guess the governments of the world have confidence in the fidelity of simulations to describe perceived reality.

This paper has interested me over the last few months because it helps me to understand the complexity of the interactions that go on in a piano when a key is pressed. My own simulations at home are an attempt to quantify some of those complexities. I do this for fun.

Edit: It doesn't make my playing any better, but it does help me to better understand the results of my tunings.


Edited by prout (01/30/14 05:20 PM)

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#2223264 - 01/30/14 05:50 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
This discussion seems to have moved from physics to metaphysics. I have always thought that knowledge is a good thing, and that what constitutes knowledge is an understanding of how something in the physical world can be described. That description is, by its nature, a simulation of the perceived reality, since the description itself does not exist outside my mind. Am I missing something here?

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#2223294 - 01/30/14 07:18 PM Re: Simultaneous partials in a string: reality or myth? [Re: prout]
Withindale Offline
1000 Post Club Member

Registered: 02/09/11
Posts: 1936
Loc: Suffolk, England
Originally Posted By: prout
Originally Posted By: Withindale
Originally Posted By: prout
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.

http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

... or read about the results of the simulations, e.g:

Observations made on real signals show that the pressure and soundboard motion spectra, including the bridge, have a denser and richer content than the strings. The simulations help here to understand these differences and identify the additional spectral components.

QED.

Sorry Ian, I don't get your point.

Thank you for the link to that paper, Prout. My point was that you don't have to wade through all the math in detail, though it helps to see how the authors built their model. The last two sections describe their results and conclusions.

The quote says that the sound of a piano is more than just the sum of the partials produced by its strings and, as you'll know, it goes on to talk about soundboard resonances excited by the initial transients.
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

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#2223299 - 01/30/14 07:34 PM Re: Simultaneous partials in a string: reality or myth? [Re: Withindale]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: Withindale
Originally Posted By: prout
Originally Posted By: Withindale
Originally Posted By: prout
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.

http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

... or read about the results of the simulations, e.g:

Observations made on real signals show that the pressure and soundboard motion spectra, including the bridge, have a denser and richer content than the strings. The simulations help here to understand these differences and identify the additional spectral components.

QED.

Sorry Ian, I don't get your point.

Thank you for the link to that paper, Prout. My point was that you don't have to wade through all the math in detail, though it helps to see how the authors built their model. The last two sections describe their results and conclusions.

The quote says that the sound of a piano is more than just the sum of the partials produced by its strings and, as you'll know, it goes on to talk about soundboard resonances excited by the initial transients.


I was particularly interested in the initial longitudinal wave and its effect on soundboard displacement downward which was consequently 'pulled up' by the the arrival of the transverse wave.

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#2223302 - 01/30/14 07:42 PM Re: Simultaneous partials in a string: reality or myth? [Re: Withindale]
pyropaul Offline
Full Member

Registered: 11/16/10
Posts: 174
Loc: Montreal
Originally Posted By: Withindale
Originally Posted By: prout
Originally Posted By: Withindale
Originally Posted By: prout
An excellent paper on the complexities of string motion and coupling on a grand piano. Well worth the effort of wading through the math.

http://hal.archives-ouvertes.fr/docs/00/78/75/51/PDF/RR-8181.pdf

... or read about the results of the simulations, e.g:

Observations made on real signals show that the pressure and soundboard motion spectra, including the bridge, have a denser and richer content than the strings. The simulations help here to understand these differences and identify the additional spectral components.

QED.

Sorry Ian, I don't get your point.

Thank you for the link to that paper, Prout. My point was that you don't have to wade through all the math in detail, though it helps to see how the authors built their model. The last two sections describe their results and conclusions.

The quote says that the sound of a piano is more than just the sum of the partials produced by its strings and, as you'll know, it goes on to talk about soundboard resonances excited by the initial transients.


Indeed, but at no point does it say that the partials in a real piano are not real. The model is an attempt to explain the real partials that are actually present - these are not abstractions, they are really there.

Paul.

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#2223369 - 01/30/14 10:40 PM Re: Simultaneous partials in a string: reality or myth? [Re: prout]
Ed McMorrow, RPT Offline
1000 Post Club Member

Registered: 12/09/12
Posts: 1957
Loc: Seattle, WA USA
Prout,
Thanks for linking the paper. I am reading it but it will take some time to fully grok it.

Discussing competing models can reach the absurdity of "number of angels on the head of a pin" at times. All models contain approximations and simplifications. I hope our fellow PW posters realize that. The real test is how useful a model is for making predictions.

I would like a better explanation of the mechanisms creating "Phantom Partials". Conklins work on I find very muddy. It could be my weak math abilities are the hindering point.
_________________________
In a seemingly infinite universe-infinite human creativity is-seemingly possible

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#2223426 - 01/31/14 01:12 AM Re: Simultaneous partials in a string: reality or myth? [Re: Ed McMorrow, RPT]
Withindale Offline
1000 Post Club Member

Registered: 02/09/11
Posts: 1936
Loc: Suffolk, England
Originally Posted By: Ed McMorrow, RPT
All models contain approximations and simplifications.... The real test is how useful a model is for making predictions.

Precisely. Choose a model, or develop one, that is suitable for the purpose. One may work for tuning, another for "improving" tone.

Interestingly, the authors of the paper consider their model as a crude skeleton of the instrument, but they go on to say:

However, even in its imperfect form, we believe that the model could be used as a companion tool for piano making. In this context, investigating the influence of soundboard modifications on the radiation of sound and on string-bridge coupling appear as potentially fruitful examples.
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

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#2223468 - 01/31/14 05:16 AM Re: Simultaneous partials in a string: reality or myth? [Re: pyropaul]
Mark R. Offline
1000 Post Club Member

Registered: 07/31/09
Posts: 1960
Loc: Pretoria, South Africa
Originally Posted By: pyropaul
Originally Posted By: Withindale
The quote says that the sound of a piano is more than just the sum of the partials produced by its strings and, as you'll know, it goes on to talk about soundboard resonances excited by the initial transients.


Indeed, but at no point does it say that the partials in a real piano are not real. The model is an attempt to explain the real partials that are actually present - these are not abstractions, they are really there.

Paul.


And that, Ian, was all this thread was about.

"Q.E.D."
_________________________
Autodidact interested in piano technology.

1922 49" Zimmermann, project piano.
1970 44" Ibach, daily music maker.

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#2223481 - 01/31/14 06:49 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: Mark R.
Originally Posted By: pyropaul
Originally Posted By: Withindale
The quote says that the sound of a piano is more than just the sum of the partials produced by its strings and, as you'll know, it goes on to talk about soundboard resonances excited by the initial transients.


Indeed, but at no point does it say that the partials in a real piano are not real. The model is an attempt to explain the real partials that are actually present - these are not abstractions, they are really there.

Paul.


And that, Ian, was all this thread was about.

"Q.E.D."

I guess I may have missed the obvious point of the thread. For me, the behaviour of the vibrating string must contain all the information needed for us to hear what we hear. Even resultant tones, which supposedly are constructed in our brains, still require the base pitches necessary. My point has always been that, at any moment in time, there is only one thing that can be measured, and that is the amplitude of something. Somehow our brains reconstruct the variations in amplitude and allow us to hear all the noise, partials, whatever, that actually exist, if you will, in the vibrating string, and the mathematics of a quantized sample, can also simulate with some fidelity, that vibrating string and allow us to appreciate its complexity.

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#2223483 - 01/31/14 07:20 AM Re: Simultaneous partials in a string: reality or myth? [Re: prout]
Withindale Offline
1000 Post Club Member

Registered: 02/09/11
Posts: 1936
Loc: Suffolk, England
Originally Posted By: prout
My point has always been that, at any moment in time, there is only one thing that can be measured, and that is the amplitude of something.

Yes. See Fig 12 in the paper: actual and simulated hammer acceleration, string displacement, bridge acceleration at string end, soundboard acceleration, sound pressure. As a simple minded exercise compare the plots of string displacement with those of sound pressure.
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

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#2223503 - 01/31/14 08:35 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
Mark R. Offline
1000 Post Club Member

Registered: 07/31/09
Posts: 1960
Loc: Pretoria, South Africa
All,

This thread has been somewhat confused by mingling different issues, e.g.
* actual string motion (as a sum of actual, real partials),
* decomposing a sound into partials and reconstituting it from them
* modelling these things mathematically
* the difference between the string's vibrational modes (partial envelope) and the actual sound generated by the soundboard (soundboard anisotropy, coupling at the bridge, etc.)

All I really wanted to find out is whether it's possible for a string to make a motion consisting of several simultaneous and real partials - preferably without the need to "disassemble".

Kees, I did read what you wrote, but I didn't necessarily understand its pertinence to the topic. (That may well be my shortcoming, not yours!)

For example:
Originally Posted By: DoelKees
A "sine wave" with a time dependent amplitude is not a sine wave. It does not even have a well-defined frequency.


And yet, notes on a piano, in spite of being time dependent, all exhibit rather well-defined frequencies, at each partial. I mean, we've been talking about these exact pitches in the temperament threads for ages. So what did you aim for with the above statement?

Or this one:

Originally Posted By: DoelKees
I assure you if you reassemble all the partials and resynthesize the sound you do not get the original sound back: just the part that is well approximated as a sum of partials.

This is really all old well-known stuff, investigated in depth in the literature. For example there is a sound synthesis method from the '80-ies by Rodet where you explicitly split the sound into something that is modeled by partials + a residual that can't be modeled like that.


It might be "old" and "well-known" to you. At least to me and Paul, non-analysable vibrations are a novelty. Also, you posted the above in a thread on string motion (not sound). Are we to understand that the mechanical motion of a real string cannot be fully described by partial analysis either? If so, I'd really like to understand this better.

Anyhow, I don't want to belabor any points, nor cause you too much trouble. I've had some partial answers wink , so for my part, this thread can go into decay. smile
_________________________
Autodidact interested in piano technology.

1922 49" Zimmermann, project piano.
1970 44" Ibach, daily music maker.

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#2223539 - 01/31/14 09:56 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1701
Loc: Vancouver, Canada
Mark,

The fact that if you remove the "partials" from the piano sound you do not get silence, demonstrates the presense of non-periodic components in the piano sound. I don't really know what to say about "a string by itself". The strings I have in my closet do not vibrate at all, know what I mean?

I don't want come over as a smart-ass know-it-all, but it is a technical topic with a large scientific literature that I am somewhat familiar with as that was my trade in the past. I think a physics forum is the place to discuss it. You can ask questions on http://www.physicsforums.com/: there are certified "experts" there that are extremely helpful for understanding at all levels.

Kees

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#2223555 - 01/31/14 10:21 AM Re: Simultaneous partials in a string: reality or myth? [Re: DoelKees]
ando Offline
3000 Post Club Member

Registered: 11/23/10
Posts: 3546
Loc: Melbourne, Australia
Originally Posted By: DoelKees
Mark,

The fact that if you remove the "partials" from the piano sound you do not get silence, demonstrates the presense of non-periodic components in the piano sound. I don't really know what to say about "a string by itself". The strings I have in my closet do not vibrate at all, know what I mean?

I don't want come over as a smart-ass know-it-all, but it is a technical topic with a large scientific literature that I am somewhat familiar with as that was my trade in the past.


Kees, I really think it would be better if you came across as a "smart-ass-know-it-all" than how you are currently coming across. I've read every post you've made on this matter and the one thing that is consistent is your refusal to back your position with detailed arguments. It's all shrouded in riddles, obfuscations and statements about how much you know about the subject, and how all answers can be found elsewhere. I don't consider this to be a healthy style of discussion. It's essentially holding yourself at arm's length from the discussion so you can't be properly challenged. I would much rather see a substantive justification of your opinion than worry about issues of modesty. So how about it? This is the place to discuss it. It is being discussed right here, right now.

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#2223561 - 01/31/14 10:28 AM Re: Simultaneous partials in a string: reality or myth? [Re: ando]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1701
Loc: Vancouver, Canada
Originally Posted By: ando
Originally Posted By: DoelKees
Mark,

The fact that if you remove the "partials" from the piano sound you do not get silence, demonstrates the presense of non-periodic components in the piano sound. I don't really know what to say about "a string by itself". The strings I have in my closet do not vibrate at all, know what I mean?

I don't want come over as a smart-ass know-it-all, but it is a technical topic with a large scientific literature that I am somewhat familiar with as that was my trade in the past.


Kees, I really think it would be better if you came across as a "smart-ass-know-it-all" than how you are currently coming across. I've read every post you've made on this matter and the one thing that is consistent is your refusal to back your position with detailed arguments. It's all shrouded in riddles, obfuscations and statements about how much you know about the subject, and how all answers can be found elsewhere. I don't consider this to be a healthy style of discussion. It's essentially holding yourself at arm's length from the discussion so you can't be properly challenged. I would much rather see a substantive justification of your opinion than worry about issues of modesty. So how about it? This is the place to discuss it. It is being discussed right here, right now.

No thanks.

Kees

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#2223665 - 01/31/14 01:47 PM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
TimR Offline
3000 Post Club Member

Registered: 08/17/04
Posts: 3187
Loc: Virginia, USA
In one sense I think BDB is right.

Of course a piano tone contains a summation of many frequencies above the fundamental. I'm not sure partial is the best term, but eigenvector while more precise is less understandable.

But the minute we talk about a wave we're talking about a visual representation, not of the sound, but of a mathematical equation.

For example. A limp string vibrating at low amplitude would produce something close to a sine wave. What does that really mean? Can you see a sine wave with a stroboscope? No, what it means is that if you took one point on that string, and measured the displacement over time, and produced a graph of the displacement over time, THE GRAPH would look like a sine wave. Not the string.

A square wave could theoretically be produced by summing the sine waves from several strings. But nowhere would a strobe show anything square looking.
_________________________
gotta go practice

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#2223957 - 02/01/14 01:28 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
Mark Cerisano, RPT Online   content
1000 Post Club Member

Registered: 01/24/10
Posts: 1134
Loc: Montreal, Quebec, Canada
Hi Y'all,

At the risk of dumbing down the conversation, I am posting a link to a video I made describing, in my own way, the harmonic series. As Kees said, it is defined by humans, for humans. And since I am a human teaching humans how to tune, I thought I would create this video to speed things up.

Some of it you might find it interesting, although it doesn't really move this conversation forward. Only to say that, as a practical application, I don't see the benefit of answering the question, although it is still interesting.

My video on the harmonic series, from the perspective of teaching a beginning piano tuning student so they may understand other aural tuning concepts that are built upon this subject, e.g. coincidental partials, etc.

http://youtu.be/dCmy6N3DnV8

Comments welcomed.

P.S. go right to the last section to hear me singing the harmonic series on one pitch.


Edited by Mark Cerisano, RPT (02/01/14 01:29 AM)
_________________________
Mark Cerisano, RPT
www.howtotunepianos.com

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#2224004 - 02/01/14 05:18 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark Cerisano, RPT]
Withindale Offline
1000 Post Club Member

Registered: 02/09/11
Posts: 1936
Loc: Suffolk, England
Good explanation, Mark.

A question; when tuning and listening for, say, the second partial do you filter out its "coincident" partials - the fourth, sixth, eighth, and so on?

In other words do you listen to it as a pure tone (second partial only) or a composite tone (even numbered partials together)?

And what about the fundamental and other partials?
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

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#2224114 - 02/01/14 10:36 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark R.]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: Mark R.


All I really wanted to find out is whether it's possible for a string to make a motion consisting of several simultaneous and real partials - preferably without the need to "disassemble".



A single audio speaker, producing a sound containing multiple partials, would have its piston moving slowly in and out at f1, and imposed on that motion is a simultaneous motion at the higher partials. This can, in fact, create a Doppler frequency shift on the higher partials as the large scale motion of the piston at f1 occurs. One more reason to use multiple drivers. Can one assume that this same phenomenon occurs on a string? Looking at an analogue waveform of the sensed vibrations clearly shows this type of amplitude variation.

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#2224119 - 02/01/14 10:52 AM Re: Simultaneous partials in a string: reality or myth? [Re: Withindale]
Mark Cerisano, RPT Online   content
1000 Post Club Member

Registered: 01/24/10
Posts: 1134
Loc: Montreal, Quebec, Canada
Originally Posted By: Withindale
Good explanation, Mark.

A question; when tuning and listening for, say, the second partial do you filter out its "coincident" partials - the fourth, sixth, eighth, and so on?

In other words do you listen to it as a pure tone (second partial only) or a composite tone (even numbered partials together)?

And what about the fundamental and other partials?


Hi Ian,

Thanks for the compliment, and for watching.

Have you heard about that crazy thing I did with my voice before? Not sure what it is called. I thought I discovered it myself (yes, I know, arrogant) but my nephew, who is an actor, said it is some kind of native thing. Not sure which natives though.

I'm not sure I understand your questions. When individual notes or intervals are played, all the partials can be heard, if your ear is trained well enough to focus on them, but it takes lots of time and practice.

So, no, it is not a figment of the imagination. I.e. there are scientific ways that we can separate the partials and look at them individually, but they are there in the whole tone. I am able to isolate specific partial frequencies when listening to a single note or interval, and then that frequency appears more prominent in my ear.

I'm sure I am not the only one, and anyone with a musical ear, who has done any transcribing or lifting of arrangements from recordings, should be able to isolate partials from a single string, especially if trying to isolate the third partial from a bass string. IME, that is the easiest to hear.

To answer your question, no, I do not think anyone can claim to hear only a pure sine wave when listening to a complete musical tone. We can only perceive the isolated partial more prominently, which helps to identify and hear beats better, for the purpose of comparing with other beats, and refining pitches on the piano.

Hope that answers your questions.

Cheers
_________________________
Mark Cerisano, RPT
www.howtotunepianos.com

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#2224131 - 02/01/14 11:24 AM Re: Simultaneous partials in a string: reality or myth? [Re: prout]
Ed McMorrow, RPT Offline
1000 Post Club Member

Registered: 12/09/12
Posts: 1957
Loc: Seattle, WA USA
Prout,
I am having a difficult time seeing how Doppler frequency shift could occur in the string medium. Doesn't a Doppler frequency shift only occur between the steady state wave source that is in motion relative to the sensing point? So the piano and listener would have to be moving in space, (space with atmosphere for sound), relative to each other for a Doppler shift to be created.
_________________________
In a seemingly infinite universe-infinite human creativity is-seemingly possible

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#2224146 - 02/01/14 11:46 AM Re: Simultaneous partials in a string: reality or myth? [Re: Mark Cerisano, RPT]
bkw58 Offline

Silver Supporter until December 19, 2014


Registered: 03/14/09
Posts: 1672
Loc: Conway, AR USA
Originally Posted By: Mark Cerisano, RPT
Hi Y'all,

At the risk of dumbing down the conversation, I am posting a link to a video I made describing, in my own way, the harmonic series. As Kees said, it is defined by humans, for humans. And since I am a human teaching humans how to tune, I thought I would create this video to speed things up.

Some of it you might find it interesting, although it doesn't really move this conversation forward. Only to say that, as a practical application, I don't see the benefit of answering the question, although it is still interesting.

My video on the harmonic series, from the perspective of teaching a beginning piano tuning student so they may understand other aural tuning concepts that are built upon this subject, e.g. coincidental partials, etc.

http://youtu.be/dCmy6N3DnV8

Comments welcomed.

P.S. go right to the last section to hear me singing the harmonic series on one pitch.


The first good, succinct, easy-to-understand video on the subject that I've seen anywhere to date. Bravo!
_________________________
Bob W.
Retired piano technician
Piano Technicę

"Never argue with a fool, people may not be able to tell you apart." - author unknown

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#2224147 - 02/01/14 11:47 AM Re: Simultaneous partials in a string: reality or myth? [Re: Ed McMorrow, RPT]
prout Offline
500 Post Club Member

Registered: 11/14/13
Posts: 779
Originally Posted By: Ed McMorrow, RPT
Prout,
I am having a difficult time seeing how Doppler frequency shift could occur in the string medium. Doesn't a Doppler frequency shift only occur between the steady state wave source that is in motion relative to the sensing point? So the piano and listener would have to be moving in space, (space with atmosphere for sound), relative to each other for a Doppler shift to be created.

Kees could do a better job of explaining I think, but, at the fundamental pitch, a single maximum amplitude displacement would occur at the centre of the string. Imposed on this displacement would be simultaneous multiple nodes occurring at the various partial frequencies. Those partials would be on a moving string, hence exhibiting a doppler shift with reference to the listener.

Edit: In the case of the speaker, and, if I am correct, a string, when it moves toward the listener the higher order partials will be frequency shifted up, and when the speaker cone or string move away from the listener, it will be shifted lower. This effect of a speaker has been measured. I don't know if this is something I could detect with FFT analysis.


Edited by prout (02/01/14 11:51 AM)

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