Outline of Violin and Effect on Sound


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On 2/28/2021 at 7:29 AM, GoPractice said:

That Greiner is "the master of assymetry?"

[...]

I have digested that quote to express that his creations are as musically symmetrical as possible. 

I think it was in one of those STRAD articles. 

https://www.thestrad.com/stefan-peter-greiner/3781.tag

'Musically speaking'i I cannot say what he is aimig at. It seems that in pursuing his musical ideas, whatever they are, he reached a sort of conclusion that building symmetry doesn't work for him. For more I suppose you have to ask him. 

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16 hours ago, plasterercaster said:

A fiddle is by definition a bowed instrument, the instrument in the fresco is plucked. Very different driver, but good luck anyway :) 

 

During the period, the same exact instruments were plucked or bowed.  Called "geigen" which is German for fiddle/violin.  Very archaic and has a guitar like bridge.  They had separate bowing bridges that could be stuck under the strings to change key and raise strings for bowing, or could be played just like a lute.

 

This is just one hair from modern violin design.  

fiddle5.jpg

fiddle11.jpg

fiddle10.jpg

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On 3/2/2021 at 4:53 AM, plasterercaster said:

The term Groß Geigen was first used in C16th German to describe viols. 

 

 

That drawing is from 1511 if I remember right.

I have working definitions of these classes which I'm sure some will disagree with:

Fiddle: any stringed instrument that can be bowed or plucked.

Viol: Tech advancement. Instrument is made like a modern violin with two plates between ribs.  Viols are fiddles but unlike medieval fiddles which were carved out of a single block of wood, and unlike bowed lutes which are formed out of multiple ribs on a mold.

Viola: Viol optimized for bowing. Finger board is lifted off soundboard and radiused. Radiused bridge.  Tailpiece lifted off soundboard. Cutouts or thinned waste to aid bowing. 

Violin: Viola with a very advanced shape. Angled fingerboard.  Soundpost and bassbar. Tall bridge. Floating tailpiece.

There are lots of exceptions.  Here's an interesting instrument. A "guitar" with a very viola like shape.  Widen c bouts make it look comfortable to hold.

fiddle9.jpg

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Here's a family of cellos made off my template.

1. Tenor. Nearly identical to Strad cello.  Little more open in the upper/center bout transition.

2. Counter Tenor: Narrower shoulders/hips than tenor.  Should have clearer treble and softer bass.  Better ergonomics for playing high on fingerboard.

3. Baritone: Broad shoulders and hips.  Full corners.  Mellow treble with crisper bass.

4. Gamba: Long c bouts to aid in pizzicato and make it more comfortable to play on knee like a guitar.

fiddles12.jpg

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4 hours ago, Marty Kasprzyk said:

Other than for bashing the right hand thumb and the bow what is the purpose of your long corner points?

If you mean on the "baritone", if (on this model) you max out the shoulders adjustment and minimize the corners adjustment then the c bouts are shaped wrong.  Max shoulders with max corners works, as does min shoulders and min corners.  If both adjustments are medium then the shape becomes very similar to the Strad.

 

This version is the least corners I can get while at max shoulders.

fiddle13.jpg

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15 hours ago, Marty Kasprzyk said:

Other than for bashing the right hand thumb and the bow what is the purpose of your long corner points?

keep up.......

On 2/28/2021 at 3:56 AM, Bran Latebarie said:

Corners are good tone filters. Reduce high pitch sound but don't effect low pitch much. Modern violins have no interior corners, but old viol designs did.  These corners filter out the bad high pitch screech but also filter out the good high pitch pierce of a modern violin.

 

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On 2/27/2021 at 10:56 PM, Bran Latebarie said:

 

>

Another big thing is that certain shapes are lava. Circles and parallel lines are horrible and tend to create standing waves like wolf notes.  The has to be a lot of asymmetry in design.  Speakers tend to be rectangular rather than cubes.  Having each dimension a little different helps break up standing waves.  Trapezoids even better.  The way violins have a larger lower bout section than upper makes it something like a trapezoid without corners.  Never seen a violin that is top/bottom symmetric but my guess is it would have a bunch of wolf tones.

>

Corners are good tone filters. Reduce high pitch sound but don't effect low pitch much. Modern violins have no interior corners, but old viol designs did.  These corners filter out the bad high pitch screech but also filter out the good high pitch pierce of a modern violin.  Getting this right in a violin is mostly in the bridge.  A good bridge produces lots of pierce and very little screech. 

>

It has near perfect cycloid "airfoil" c bouts.  Cardiod upper and lower bouts which is a nice shape that reflects and focuses waves but doesn't produce standing waves and tiny little exponential corners that should only filter the very highest frequencies. 

Bran made some good points about points.   

Anechoic foam materials are shaped with points to trap sound waves and prevent their reflections that would cause resonances.  

Screen Shot 2021-03-04 at 9.45.49 AM.png

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1 hour ago, Marty Kasprzyk said:

Bran made some good points about points.   

Anechoic foam materials are shaped with points to trap sound waves and prevent their reflections that would cause resonances.  

Screen Shot 2021-03-04 at 9.45.49 AM.png

What are they used for? Do they take away natural room reverb so that sound engineers can add digital reverb instead?

Is that why the old recordings sound better?

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31 minutes ago, sospiri said:

What are they used for? Do they take away natural room reverb so that sound engineers can add digital reverb instead?

Is that why the old recordings sound better?

What happens is acoustically complex.  Made these drawings to attempt to illustrate.

1st 2 waves are a combination of a high frequency and low.

2nd pair of waves is "muffled".  I've done something to reduce the amplitude of the high frequency while leaving the low frequency alone. Lots of ways to do this. Wood is a good muffler as is fiberglass packing.

3rd pair of waves is what I call mellow crispiness. Rather than just reduce the high frequency, I've modulated the amplitude using the low frequency. It's very pleasant compared to muffling. Perfect quiet between the low frequency beats but the highs are just as loud at the peaks of the low frequency.  Crispiness is the ability to hear the precise beginning of a tone which is very difficult with lower frequencies.  By using this amplitude modulation it makes it sound like you can hear a definite beginning and end of each low frequency wave.  Completely different than "booming" bass.  You can try to hear the bass better by increasing the amplitude, but crispiness allows you to hear the bass better without increasing the volume which sounds better.

 

Corners create mellowing and crispiness.  Why?  Science...LOL  Not really sure, but the way I think about it is like waves on a beach.  A sandbar, place off the beach with a shallow depth causes high frequency waves to crash but low frequency waves pass right over it like it's not there.  But just as a low frequency wave passes over the bar, the sea level rises and now the high frequency waves can pass over the bar along with and in phase with the low frequency wave trigger.

 

Something similar happens in speakers.  The corners trap the high frequency waves, but when a low frequency wave passes by, it releases all the high frequencies.

waves.jpg

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Mr. Lateberie, why would you consider speaker design to be analogous to fiddles? One can make a highly damped and inefficient speaker design, and overcome that by just pumping in more electricity. Acoustic instruments are a bit different.

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39 minutes ago, David Burgess said:

Mr. Lateberie, how do shapes or materials used in anechoic chambers relate to the production of good-sounding violins? Will a violin (or a trumpet)  lined with foamed rubber produce a superior sound? I'm thinking not. Maximum damping is not what we are going for.

Nor do I consider speaker design to be analogous. One can make a highly damped and inefficient speaker design, and overcome that by just pumping in more electricity. Acoustic instruments are a bit different.

I'm running with several subjects here so forgive me.

1. I have a math model of the violin shape and have taken it to extremes on what I still consider to be a violin shape.  How skinny can it get and still be a violin?  How fat can it get and still be a violin?  How wide can the c bouts get and still be a violin?

2. I think speakers and violins probably have a lot in common when it comes to the physics.  I bet if you took a violin body and cut a big hole in front and mounted a speaker driver, it would sound pretty good, lol.  If so, the reverse is probably true as well.  Also the hi fi sound industry is a multi bjillion $$ industry with lots of really smart people trying to figure out how to make speakers sound better.

So taking lessons learned from speakers and applied them to changing shape of the violin.

IF I were to try to build a thinner violin which may have advantages in the high range.  Better ergonomics for fingering high on board, and a smaller area front plate.  Rules for speakers when you do this are some things can not change.  The total volume of box must remain the same. In a violin, if you reduce area of front plate, then the ribs must get wider to compensate so internal volume doesn't change.  The size of the vents (f holes) can not change.  The mass and flexibility of the the driver (front plate) can not change.  So the thickness of the front plate would have to increase while at same time it would have to become more flexible because distance across is reduced.  This might be the most difficult challenge to make is sound good.  Maybe a different type of wood would have to be used on the front plate that is both denser and more flexible than spruce.

And there are always trade offs.  Maybe you could produce a violin with clearer and more piercing highs than normal, but this WILL come at the expense of reduced mellowness and crispiness of the lows.  This is always true of speakers and there is no free lunch.

 

BTW I'm trying for a free lunch with my gamba design. Widening the shoulders increases front area, while widening the c bouts decreases area.  Get them both in balance and frontal area stays same as conventional cello.  Hopefully this means that conventional front plate profile, thickness and material works fine, although the f holes will have to change.  I'm thinking something more shaped like a J.  A c hole would fit but would radically change the flexibility of the plate in the bridge area which is a no no.

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A lot of the sound that we identify as «a violin» or being violin like, is related to the bowed string and the skills of the player. Every now and then somebody put a neck, a bridge and strings on a cigar box, and play it. It does sound much like a violin, especailly if a skilled player plays it. 

We hear that the cigar box lack some lows. It certainly does not sound like a great violin. But much of the traits of violin sound is there.

Joe Curtin does a demo of this every now and then, I guess as a convoluted signal from his electric violin setup which runs with data from measured impulse responses of violins or any other object with some acoustic response.

I have tried a fiddle with a very narrow body for easy transport in Helicopters for jobs in the oil industry. It sounded surprisingly ok, fair enough for practicing in off shore sleeping compartmants with so-so sound insulation. I have also filled a violin body with cotton reducing its low frequency response. It still sounds much like a violin. 

One interesting question is: How large must the geometrical changes be in a model for it to be audible? And where should we expect the changes to happen in the frequency response?   

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On 3/4/2021 at 10:53 AM, Bran Latebarie said:

I think speakers and violins probably have a lot in common when it comes to the physics. 

That's what I thought too before I made a few violins.  Getting that model out of one's head I think is important in order to find out what it really takes to make decent instruments.  Speakers might be an OK model for the A0 mode, but that's only a factor on a few notes on the C string.  The violin is a lot more than that.

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