Can a flat topped/bottomed violin be made to sound like a regular arched violin?

[LCF]

Back on topic. Here's another type of bowed string instrument with a flat soundboard plus a different solution to the soundpost issue. No post is required since one leg of the bridge sits on the rim to give the rocking motion of the other foot. 

 

https://youtube.com/shorts/Iej3K_JB7cA?si=wT3J54wPl8tlZLUu

 

I have vague suspicions about that bow action vs Sawzall (tm) motion.

 

 

[Marty Kasprzyk]

On 5/19/2024 at 5:07 PM, Anders Buen said:

Probably not. The lows will be stronger than normal (given the same graduations) and the highs may not develop as well as on an arched violin. One major problem may be the worse behavior during humidity cycling than an arched instrument that may follow the variations easuer without cracking.

Hermann Mayer made a flat topped trapezodial violin as well as normal ones with high and low arching and documented them acoustically. His german PhD article was translated and republished quite recently in the VSA Papers.

Link to paper: 

Integrating the area underneath Meinel's three different arch plots shows that a flat plate produces the highest total sound pressure output and that increasing the arch height reduces the sound output.

I had mentioned earlier that a flat plate should be a more efficient sound producer because there is no vibration energy wasting in-plane plate deformation which arched plates have.  Meinel's experiment is evidence of that.

[Don Noon]

34 minutes ago, Marty Kasprzyk said:

Integrating the area underneath Meinel's three different arch plots shows that a flat plate produces the highest total sound pressure output and that increasing the arch height reduces the sound output.

I had mentioned earlier that a flat plate should be a more efficient sound producer because there is no vibration energy wasting in-plane plate deformation which arched plates have.  Meinel's experiment is evidence of that.

The same type of analysis shows that Meinel's overly thin plate produces more sound than a normally thicknessed one.  If your hearing cuts off at 1500 Hz and louder is always better, then a flat plate or very thin arched one might be to your liking.

There are other things to consider.  Loudness is not just a function of efficiency, but impedance matching as well.  The Meinel excitation is from a mechanical bowing machine, and who knows how impedances match up.  From the results, I would expect that the low impedance of the flat plate and thin plate just take more energy out of the bowing system, and the in-plane vibration is a red herring.  Much like a 4 ohm speaker will be louder than an 8-ohm one... if the amplifier can put out the amps.

Focusing on loudness and efficiency at the expense of tonal balance might get you a loud instrument that nobody likes.  A "good violin" is not something that can be boiled down to a few numbers.

[Marty Kasprzyk]

12 hours ago, LCF said:

 

Marty do you have a cross brace on the back underneath your thru posts? Eg as on the flat back of a double bass viol type.  Many of the so called 'ancient' types have very solid back shells, usually they are carved like giant spoons so the insides are lute shaped for instance as opposed to violin or guitar shaped. 

 

'Ancient' lol. Several types are still being played, and appreciated by hundreds of thousands of people, millions. 

My back plate is made from 0.8mm birch plywood which is quite floppy.  It is bent to mimic a shoulder rest shape (attached photo of the current one I'm building) and internal cross and longitudinal braces will be added to it to stiffen it after it is glued to the rib assembly. 

In the past I used Paulownia wood braces.  I might next try using balsa wood with carbon fiber tape added to their top edges to further reduce their weight.

[Marty Kasprzyk]

2 hours ago, Don Noon said:

>

Focusing on loudness and efficiency at the expense of tonal balance might get you a loud instrument that nobody likes.  A "good violin" is not something that can be boiled down to a few numbers.

Blind tests have shown players generally prefer louder violins over weaker ones as shown in the attached graph which uses a few numbers.

But loudness isn't the only important factor and there are other things are also important such as tonal balance, evenness, etc.  For example, the attached graph shows several violins had the same loudness but some are liked better because of these other qualities.

 

[Marty Kasprzyk]

11 hours ago, LCF said:

Back on topic. Here's another type of bowed string instrument with a flat soundboard plus a different solution to the soundpost issue. No post is required since one leg of the bridge sits on the rim to give the rocking motion of the other foot. 

 

https://youtube.com/shorts/Iej3K_JB7cA?si=wT3J54wPl8tlZLUu

 

I have vague suspicions about that bow action vs Sawzall (tm) motion.

 

 

Thanks for the video link! 

I suspect that having one bridge foot resting on the rim is better than it resting on a soundpost going through a hole in the top plate.  I'll add it on my list of new-old things to try.

Should it rest on the treble or the bass side?

[Don Noon]

1 hour ago, Marty Kasprzyk said:

Blind tests have shown players generally prefer louder violins over weaker ones as shown in the attached graph which uses a few numbers.

But loudness isn't the only important factor and there are other things are also important such as tonal balance, evenness, etc.  For example, the attached graph shows several violins had the same loudness but some are liked better because of these other qualities.

I think we are in agreement, mostly.  Yes, a traditionally constructed, arched violin (as in the Fritz tests) most likely will have some basic tonal trends, and then loudness can be a significant factor.  A violin I made was selected over a Strad to play in a concert for that very obvious reason.

However, if you start doing non-traditional construction for the express purpose of overall loudness, I would expect difficulty in keeping the tone and playability at a level that a good violinist demands.

And then there's the issue of acceptable appearance, which is still currently stuck at 300 years ago.

[Andreas Preuss]

1 hour ago, Don Noon said:

And then there's the issue of acceptable appearance, which is still currently stuck at 300 years ago.

If you could convince with a new model the majority of superstar violinists maybe anything would go….

 

,,. however in the meantime balanced deformations seem to be second best option to this problem.

[LCF]

On 5/28/2024 at 10:05 AM, Don Noon said:

...   For A0, certainly everything is coming out of the F-holes, as confirmed by my test of covering them with tape (A0 disappeared completely).  For the B modes, more than half the power is from the F's.  In my tape test, the peaks were still there, but down a few dB.  

I think there is a significant confounder there. Tape is not rigid enough to eliminate some of the effects of the holes and can still get some radiation plus some detuned cavity effects. You need something much more rigid like a piece of wood or plastic sheet and something to make it airtight.

[Marty Kasprzyk]

10 hours ago, LCF said:

I think there is a significant confounder there. Tape is not rigid enough to eliminate some of the effects of the holes and can still get some radiation plus some detuned cavity effects. You need something much more rigid like a piece of wood or plastic sheet and something to make it airtight.

You're right that something more rigid than tape is needed but this is a difficult experiment to do.  If you tape on a sheet of plastic or wood over the f hole it restricts the vibration of the "island" area between the f holes which also affects the sound so it is not certain what causes the change in sound character.

George Bissinger  had a better testing method. He measured the violin's total sound out put with a spherical array of 266 microphone positions around the violin in an anechoic chamber.  He then measured the sound out put from the f holes (h) with a 9x12 patch array of 108 microphone points very close to the f hole openings.

He  subtracted the f hole sound (h)from the total(t) to get the amount coming off the violin's surface (s).  The ratio of the f hole sound (h) to the surface sound (s) gives the fraction (F) coming from the f holes F= h/s which is plotted vs. frequency which I had attached earlier which shows a very large portion of the violin's low frequency sound output is from air flow through the f holes. It's not just the A0 resonance.

I don't have the resources, time or smarts to this kind of testing so I just take his word for it.

 

[Marty Kasprzyk]

On 5/27/2024 at 8:35 PM, Don Noon said:

The log plot is a bit misleading, as it looks visually like F-hole radiation is more than it really is.  It should be a linear vertical scale.  For A0, certainly everything is coming out of the F-holes, as confirmed by my test of covering them with tape (A0 disappeared completely).  For the B modes, more than half the power is from the F's.  In my tape test, the peaks were still there, but down a few dB.  Above that, only one resonance has "most" of the power from the F's, probably a higher-order air resonance effect.

I'll pass on getting into the weeds on speakers, which can have a variety of factors influencing their design and manufacture that have nothing to do with violins.

Even this discussion about radiation efficiency and power is only academic... it can't tell you what sounds good, and can easily be misleading.  And related to the OP's original question, we still can't say for sure, and it's a lot like the question of why nobody has been able to surpass a Stradivarius .

 

Bissinger's log plot is indeed misleading, but a linear plot actually shows the F-hole radiation from a body volume change is more important than it visually appears in his log plot.

Flat panel speakers have some similarities to flat plate violins--both use flat plates and both produce sound.

Not all Stradivarius violins are great and little effort has been made to explain why or even admit it.

 

[Don Noon]

3 hours ago, Marty Kasprzyk said:

Not all Stradivarius violins are great and little effort has been made to explain why or even admit it.

Plenty of effort has been put into analyzing the good and bad Strads... without any earthshaking results, and most researchers are reluctant to publish a paper that says nothing.  The following also applies to that kind of research:

Among folks who deal with lots of Strads, it is known that some are great, some are not, and some are pretty bad.  It's poor form to publically point out the bad ones, especially when the owner has a couple million invested in it and knows who you are.

[LCF]

On 5/30/2024 at 2:26 AM, Marty Kasprzyk said:

Thanks for the video link! 

I suspect that having one bridge foot resting on the rim is better than it resting on a soundpost going through a hole in the top plate.  I'll add it on my list of new-old things to try.

Should it rest on the treble or the bass side?

Interesting question. I've seen pics of Sarangis with both. For those which have very narrow waists at the position of the bridge and a narrower string band hence narrower bridge it might not matter much.

 

Another interesting feature of the Sarangi is that the first string seems to always be gut. Or perhaps it's silk gut ( caterpillar)?  They seem very stable and durable whatever they're made from.