Is the research on violin acoustics a viscious circle?

[John Harte]

Probably not adding anything here...

Below are a couple of fairly crude spectra that I produced something like 30 years ago.  The handwritten titles/comments are self explanatory.  Horizontal axis is frequency with G fundamental at 196Hz..  With respect to the bowed G, I recall the relative overtone strengths varying depending on bow pressure, speed and contact point etc..

[Don Noon]

I did some analysis on one of my violin bowed semitone scales...

Comparing open G to C# (where the A0 resonance is strongest), the C# is 1.4 dB louder... not a huge amount.

Equalizing down the fundamental of the note by -20 dB, the open G loses 0.1 dB, the C# loses 1.2 dB, and their loudnesses are essentially the same.

My conclusion is what I thought:  a strong fundamental on the low notes adds a little power, but not a huge deal.  Tonally it might be more obvious.

[Oscar Stern]

Carleen Hutchins made this Octet of Violins that are all proportional in both size & pitch. The 4th instrument is the Alto Violin aka Upright Viola. It has a 20 inch body which is big enough to resonate fully, but it's also big enough that you can play it like a Cello by using the end pin. This relieves weight off your shoulders but it also allows the sound to be projected towards the walls.

[Marty Kasprzyk]

10 hours ago, jezzupe said:

Marty I notice some of your models have round sound ports drilled in the tops, some with 2, some with 4 and some with none.

Can you describe the effect that has? is there a volume difference, tone difference, better, worse one way or another?

One of the things I experiment with is doing graduations as I normally would, cut decorative holes in the top {usually in more "lung central" locations than your outer nodal areas at the edge} and then patch over the holes from the inside a dissimilar material such as thin epoxied balsa, or very thin hardwoods

I notice in many of these attempts an increase in over all amplitude as In many cases I will setup the violin without the top cut out , then pull the top and cut it out just to be able to see if what I do makes it better or worse, louder or not.

I would like to make some models with sliding sound port that can be opened or closed

The additional holes can be easily plugged with corks and they influence the A0 and A1 frequencies and their amplitudes. I believe the viola with 4 holes can give 24 combinations of open and closed holes (from 4x3x2x1).  So a viola player can make many experiments to find their favorite combination.  It's hard to remember each of these so many tests are repeated which provides nearly endless fun.

One unusual result of using an open hole in the lower bout is that the player hears for the first time a lot of sound in his right ear and the effect is like being inside the instrument with surround sound.  Some players liked this effect and this is helpful if you want to wreck your hearing in both ears equally.

[jezzupe]

2 hours ago, Marty Kasprzyk said:

The additional holes can be easily plugged with corks and they influence the A0 and A1 frequencies and their amplitudes. I believe the viola with 4 holes can give 24 combinations of open and closed holes (from 4x3x2x1).  So a viola player can make many experiments to find their favorite combination.  It's hard to remember each of these so many tests are repeated which provides nearly endless fun.

One unusual result of using an open hole in the lower bout is that the player hears for the first time a lot of sound in his right ear and the effect is like being inside the instrument with surround sound.  Some players liked this effect and this is helpful if you want to wreck your hearing in both ears equally.

I see, very cool

[Don Noon]

13 hours ago, Oscar Stern said:

Carleen Hutchins made this Octet of Violins that are all proportional in both size & pitch. 

The thing about scaling is that various structure, air, and acoustic formulas scale differently with size, so you can never get a true scaled-up violin that will have the acoustic output scaled down in frequency.  Even if you could, it would sound like its own instrument to the human ear, anyway.

Re: the alto violin (or vertical viola), shifting the air and body resonances lower in frequency so that there is some support for the fundamentals on the C string would give it some low-end roundness that can't be had on normal viola sizes.  It doesn't qite sound like a cello or a viola, which I think is the only interesting thing about the octet.

[Michael Darnton]

https://old-violin.com/rare.html

[jezzupe]

25 minutes ago, Michael Darnton said:

https://old-violin.com/rare.html

I love the one with tower just kinda stuck on there lol

[Andreas Preuss]

22 hours ago, Marty Kasprzyk said:

So why were the original violins designed 500 years ago to produce weak notes on the G string?

Half way, I think you gave the answer yourself in your experiments. I think that their methods restricted them to 
 

The construction method of Cremonese makers came from aesthetic ideals and pragmatic considerations. ‘Beauty’ and ‘Harmony’ had their expression in ‘symmetry’ and ‘proportional balance’. No one less than Descartes (a contemporary of Niccolò Amati) still believed that the movement of the universe was based on a (magic) universal harmony. So asymmetric constructions were definitely not regarded as logic towards the goal. 
 

In practice the simple use of an internal mould made sure that the sketched out harmony could be easily repeated and duplicated. Therefore acoustic considerations were, on that level, secondary, and even if makers noticed weaknesses on the G string they could get along with that. (Considering how minimal the effect is)

one would have to break with those basic rules to do something else.

None of your designs follows those rules. And the tenor viola, which would have been a solution, got abandoned presumably because of un-playability. OTOH your success is based on the same principle as makers in the Cremonese school: repeated trial and error until all weaknesses (whatever you define as such) are eliminated. That’s the hard part. 
 

(always with admiration for your daringly different approach. 

[Andreas Preuss]

4 hours ago, Michael Darnton said:

https://old-violin.com/rare.html

Samples of inventions (presumably to ‘improve’ the sound) repeating one big mistake: Omitting tests with violinists.
Any modern product designer knows that this approach doesn’t work. That’s why in the modern design world the MVP (Minimal Viable Product) was introduced for first test runs. The feedback from there provides the know how to design a product to the needs of the end user.

[Dr. Mark]

On 6/13/2023 at 3:27 AM, Andreas Preuss said:

‘Beauty’ and ‘Harmony’ had their expression in ‘symmetry’ and ‘proportional balance’. No one less than Descartes (a contemporary of Niccolò Amati) still believed that the movement of the universe was based on a (magic) universal harmony.

Yep...and Johannes Kepler https://en.wikipedia.org/wiki/Mysterium_Cosmographicum and, earlier but part of the same movement, da Vinci https://en.wikipedia.org/wiki/Vitruvian_Man and Brunelleschi https://en.wikipedia.org/wiki/Filippo_Brunelleschi - there were many others in the arts and sciences who followed the same path.  Some of these ideas had legs and are still very influential either directly or consequentially today.  Which leads me, at any rate, to mathematics.  There's a trigonometric identity that allows us to write:

A*sin(a) + B*sin(b) = (A-B)*sin(a) + 2*B*sin[(a+b)/2]*cos[(a-b)/2]

where A and B are amplitudes, a = w(a)*t and b = w(b)*t are cyclic frequencies times time t. 

The left hand side is the Fourier expansion of the right-hand side, so the power spectrum is non-zero only at frequency w(a) cycles/second with magnitude A squared, and at w(b) cycles/second with amplitude B squared.  The power spectrum is the square of the Fourier transform - details omitted.

What's interesting is that a pressure wave excited by these two frequencies is described by the right-hand side, so what impinges on the microphone has frequencies of w(avg) = (w(a)+w(b))/2 which is the average frequency, w(diff) = (w(a)-w(b))/2 which is the beat frequency, and an excess at w(a) with amplitude (A-B).  We won't see the former two in the spectrum.  So if b is an nth harmonic and a is the (n+2)nd harmonic then the beat frequency is the fundamental and we could hear it even though it isn't played.  All very interesting stuff.

As usual - please correct me if I make a mistake.

Edited June 15, 2023 by Dr. Mark
correction

[Don Noon]

Not specifically related to recent posts, but after 16 pages I'm coming to the conclusion that acoustic research is not so much a circle but a 6-dimensional  nebula composed mostly of dark energy.

[Michael Darnton]

Dark energy called me. She is insulted. 

[martin swan]

12 hours ago, Andreas Preuss said:

Samples of inventions (presumably to ‘improve’ the sound) repeating one big mistake: Omitting tests with violinists.
Any modern product designer knows that this approach doesn’t work. That’s why in the modern design world the MVP (Minimal Viable Product) was introduced for first test runs. The feedback from there provides the know how to design a product to the needs of the end user.

The requirement of the end user is “a violin”. That exact product is already available, and in some quantity.

Maybe the real question is how any single maker out there might reasonably differentiate themselves from the vast number of other makers apparently doing exactly the sane thing …

 

[Violadamore]

1 hour ago, Michael Darnton said:

Dark energy called me. She is insulted. 

LIKE!!!! 

[Marcus London]

Viscosity is something else. Does it affect varnish? Do you have to let it dry to get a strong enough sound?