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

[Dr. Mark]

6 hours ago, Anders Buen said:

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.

and, for example, I bet all of his tops were spruce which may not be the ideal for a flat plate violin, and the same varnish on all of them.  I don't know - I hope at least that his results are repeatable/repeated.  But the plots don't illustrate tonal quality.  Don't get me wrong - I'm a fan of what meaningful experimental and theoretical work you and Mr. Noon and Mr. Kasprzyk are winkling out of violin acoustics.  But I don't think you're answering the OP's question, even if you can (but I don't think you can) show that flat top and normal violins must have an inherently unique and distinguishable tonal quality that prevents a flat-top violin from sounding like a good (however much it needs to be) normal violin.  I don't think anyone can answer the OP's question except himself.

I guess we could claim that if spectra matched identically then tonal quality would also match, and from there add that if the spectrum of a violin is in some way measurably 'closer' to a reference than that of another then the reference and the one with the closer spectrum sound more similar.  That could lead us to assert that a persistent spectral difference (perhaps like that shown) between flat-top fiddles and normal fiddles means that a normal fiddle will always sound more like a normal fiddle than a flat-top fiddle, and visa-versa.  Could anyone back up such assertions with experimental evidence?  Does anyone believe all that?

Maybe it's not important - flat-top violins aren't contenders, and I doubt ever will be much more than a curiosity or an experiment - except among the cigar-box contingent.

6 hours ago, Anders Buen said:

Probably not.

Probably not what? 

[Dr. Mark]

2 minutes ago, Don Noon said:

There can never be any absolute definition of tonal quality, since it is subjective and listenerplayer dependent.

As for an answer to the OP's original question, that too is impossible to answer for sure, due to the same basic reason.  However, I think there are some significant physics and acoustics differences between flat and arched soundboards, and if you define a "great" sounding violin as an existing arched violin, and need to match that with a flat plate version, these fundamental differences might make the task very difficult or even impossible to achieve.

Or you could just make a flat plate violin and say it sounds great.  Nobody could prove you wrong.

I'm happy to say I agree with you.

[Anders Buen]

7 hours ago, Dr. Mark said:

Probably not what? 

Answering the tread-starter heading question.

[LCF]

In my teens, aiming to shortcut archtop mandolin building, I made some mandolins with flat tops and backs. Some of the more lightly built ones did not last very long. 

The op question leads to an interesting assortment of considerations. A conventional violin design is immensely strong vs the materials it is made from. It is a strong shell with structural help from bassbar and soundppst. Total end to end string forces are of the order if 200 to 300N and downbearing at bridge  approx 30N at each foot.  I guess the arched shape of the top contributes to the ability to resist the downbearing. What I don't know is whether an arch  carved from solid is stronger or weaker than one which is made curved from flat pieces of the same material and dimensions A laminated plate obviously can be stronger if properly designed. 

With a flat plate there are difficulties in setting the downbearing via the break angle versus neck angle but ignoring that the biggest challenge is making the flat top strong enough that it doesn't quickly collapse inwards (and belly up in the bouts). Lamination, slight arching and various bracing patterns are obvious  solutions to that challenge.

It's hard to get away from the fact that Marty Kasprczyk has apready worked his way rather elegantly through all of these issues!

 

 

Edited May 20 by LCF
Cleaned up my act a little

[LCF]

Edit: Kasprzyk

I will type it 100 times before sunset. 

[Andreas Preuss]

On 5/16/2024 at 3:27 AM, Aston4 said:

I'm starting to consider making my first violin body. Of course the arching is intimidating to me.

Does the arching actually add enough to the sound to be one of the main factors making a violin sound like a violin?

Yes I'm aware of vielles and the like, and how they sound, but I don't know how much of the sound difference is in the shape vs other stuff, e.g., soundpost.

I listened to the example of a... differently shaped viola here a few days ago, and it more or less had viola sound, at least through speakers. I've also found youtube demo's of fiddles made from foam, plastic, etc, that sound more or less like normalish violins.

I guess my question really is, can a "great" sounding violin me made, in violin shape, but without arching, just flat pieces of wood top and bottom? Surely many must have tried at some point.

 

 

Flat doesn’t work. But you could bend a flat plate lengthwise over an arched rib garland. Might bring a very interesting results. (No guarantee)

[JacksonMaberry]

2 hours ago, Andreas Preuss said:

Flat doesn’t work. But you could bend a flat plate lengthwise over an arched rib garland. Might bring a very interesting results. (No guarantee)

I'm sure Marty has done that and can comment.

[Dr. Mark]

3 hours ago, Andreas Preuss said:

Flat doesn’t work

With all due respect - I only object because, from the conversation above and despite the expectations of the experienced makers here, this appears to be a conclusion by fiat rather than by the weight of evidence.

[Aston4]

6 hours ago, Andreas Preuss said:

Flat doesn’t work. But you could bend a flat plate lengthwise over an arched rib garland. Might bring a very interesting results. (No guarantee)

Until very recently I thought violin tops and backs were probably formed over molds.  Even after decades of playing, I never bothered to look into it.  I thought about it, briefly, a few times, but figured carving a shape like that would probably be too difficult and time consuming, as well as haphazardly unreproducible.  I also thought a carved top would probably be weaker than a formed top (maybe it is?).  As a pure player, the construction of a violin was a mysterious process, and most all maintenance to be strictly by the luthier.  Trying to change a tailpiece twice and dropping the soundpost both times(and failing attempts to reset the post myself both times) reinforced this way of thinking.  My only concerns were playing better and composing more.  If I wanted better tone, I considered my options to be opening my wallet for better equipment, or additional bitching at my luthier.

[jezzupe]

To the best of my knowledge flat tops and fat bottoms only work well in the rockin' world.

I built this in a day for kicks long ago, sounded like a pochette

 

\

[Don Noon]

7 hours ago, Andreas Preuss said:

Flat doesn’t work.

It depends on how you define "work".  It is possible to make flat plates produce sound and survive for a bowed instrument.  It doesn't work for my ear, though.

[Andreas Preuss]

4 hours ago, Dr. Mark said:

With all due respect - I only object because, from the conversation above and despite the expectations of the experienced makers here, this appears to be a conclusion by fiat rather than by the weight of evidence.

I understood the OPs question as trying to make things as easy as possible in constructing a ‘normal’ violin. And just making a flat top on an otherwise Strad model structure is not working even if the rib height is adjusted to compensate for the lost air volume. It is rather possible to make a flat back. I have once heard such a violin and it was sound wise good enough to justify the alteration.

——-

This brings me always back to think in violin making about basic concepts. The Cremonese concept is after 400 years explored the best and therefore optimized the best. I understand its limits as lying somewhere in the balance between ‘sound power’ and ‘sound flexibility’. In this respect I understand current acoustic research as finding best strategies to calibrate the sound in a desired direction but seems altogether a pretty tricky task.
 

Therefore I think that if we really want to make violins with more sound power without sacrificing other important sound related qualities, we need to think and work first of all on a different concept. And this includes also a building procedure which facilitates the sound calibration. So in the end it is not about ‘sound improvement’ but rather more controllable and less complicated ways to reach the goal. 

From what we can learn about any concept different from the Cremonese. It’s a long way to get acceptable results or results which are usable within the ideas of classical composers. 

[Andreas Preuss]

26 minutes ago, jezzupe said:

To the best of my knowledge flat tops and fat bottoms only work well in the rockin' world.

I built this in a day for kicks long ago, sounded like a pochette

 

\

Could be used also for kids when building instruments. My kids were in a school where they had in grade 3 an instrument building project.

[Anders Buen]

I heard a concert once played on a Chrotta, a flat plated violin like instrument with the right bridge foot on the soundpost through a hole in the top. It souded violin like, as all gestures and bowing the string as well as vibrat etc contributes to the impression. On a detialed level I do not think it souded like a typical violin, although there were clear similarities. 

I guess some of Martys instruments may have some similarities. 

[Andreas Preuss]

28 minutes ago, Anders Buen said:

I heard a concert once played on a Chrotta

Interesting. What was performed? 

[LCF]

10 hours ago, Aston4 said:

Until very recently I thought violin tops and backs were probably formed over molds.  Even after decades of playing, I never bothered to look into it.  I thought about it, briefly, a few times, but figured carving a shape like that would probably be too difficult and time consuming, as well as haphazardly unreproducible.

# Some violins have been made partly formed by molding. 

# It is time consuming and can be difficult.

# No two makers seem to reproduce exactly the same violins. It's like handwriting.

All is not lost however. I know that David Burgess is very fond of his Sawzall (tm) for automating tedious chores associated with violin making but not only could you be one of the pioneers of arching and fingerboard planing plus bridge fitting via Dremel Mototool but even more exciting would be the possibility of arching plates by the use of these disks in an angle grinder:

https://www.amazon.com.au/Carving-Grinding-Attachment-Circular-Chainsaw/dp/B094QYP9X1

That's all the thrills of carving with a chainsaw without the bar and chain oil splashing all over the kitchen table. 

BUT

It will take your leg off if you slip and you will die.  You have been warned!

 

 

 

 

 

 

[Anders Buen]

15 hours ago, Andreas Preuss said:

Interesting. What was performed? 

I do not remember now, it is more than 20 years ago. But the performer was Rupert Blom, I think. A nice Bergen guy. It was a pair her name was Gisela Blum-Feldhusen, and they had a bacground in Stainer philosophy and teaching. Very nice to talk with. I think they both were Stainer school teachers, and he stated and demonstrated that music should be experienced from behind. I still remember the reddish a bit smaller instrument. He also had and played a real chrotta with the two stabilizers from the neck. I think they originally both were German. And they lead a "Fana Unge Strykere", a chamber music group of young players in Fana in Bergen until 2013.

I have read one of Rudolph Stainers books. I think he wrote 400. I liked it. Borrowed it from my sculptor aunt. 

Edited May 21 by Anders Buen
Added some information

[Marty Kasprzyk]

On 5/21/2024 at 2:06 AM, Anders Buen said:

I heard a concert once played on a Chrotta, a flat plated violin like instrument with the right bridge foot on the soundpost through a hole in the top. It souded violin like, as all gestures and bowing the string as well as vibrat etc contributes to the impression. On a detialed level I do not think it souded like a typical violin, although there were clear similarities. 

I guess some of Martys instruments may have some similarities. 

I believe the inventors of the arched plate violin, about 500years ago, made a mistake of abandoning the then traditonal use of flat plates.

Colin Gough has shown that when the bridge's vibrating force pushes down on the convex arched top plate that the top plate deforms with an out of plane movement which produces helpful volume changes but it also produces an in-plane motion which spreads out the top plate.

Since the top plate and back plate are connected with the sound post the convex back plate also is deformed at the same time.  The downward force again produces useful out of plane movement but in this case the in-plane movement in inward which shortens the back plate.

Thus the top plate expands in length and width while the back plate shrinks.  This causes the whole violin body to bend while it also has a volume change. The important low frequency sound producing modes B1- and B1+ are a combination of the volume change and bending movements as shown in Colin's attached diagram.

A violin is too small to effectively produce low frequency long wave length sounds directly from its plate surfaces so most of its low frequency sounds up to about 1000Hz are produced from volume changes of its body which produces air flow through the f holes.

Therefore all of the body bending deformation energy is wasted by not producing any sound.

Notice in Colin's diagram that the in-plane plate deformation is proportional to the arch height h squared. This suggests that lowering the arch height should waste less energy and that a flat plate is a more efficient low frequency sound producer than an arched plate because there will be no wasteful body bending.

I believe arched shape was originally adopted to stiffen the top plate to better resist the increased downward string force that occured from using a high curved bridge needed for the then new playing technique of individual string bowing.  The increased plate stiffness did helpfully increase the high frequency sound output.

But a more efficient stiffness increase could have been acheived by using internal braces on flat plates such as guitars and other instruments traditionally used.  

[Don Noon]

2 hours ago, Marty Kasprzyk said:

 

"I believe the inventors of the arched plate violin, about 500years ago, made a mistake of abandoning the then traditonal use of flat plates."

We would now be arguing the topic, "Can an arched violin be made to sound like a regular flat-plate violin?"

"A violin is too small to effectively produce low frequency long wave length sounds directly from its plate surfaces so most of its low frequency sounds up to about 1000Hz are produced from volume changes of its body which produces air flow through the f holes."

To be a bit nit-picky, only the A0 gets a significant boost from F-hole flow.  B modes are too high in frequency for the Helmholtz resonance to help, and most of the sound comes from the outer surface of the instrument.  Covering the F holes kills off the A0, but the B modes are still mostly fine.  Yes, the frequency is still low enough (thus wavelenght long enough) so that volume change is needed to produce decent radiation.

"But a more efficient stiffness increase could have been acheived by using internal braces on flat plates such as guitars and other instruments traditionally used. "

To what end goal?  More A0 and B mode power?  That can be achieved quite easily on a normal violin by making it thinner, yet that approach doesn't seem to be all the rage.  At higher frequencies, it has been mentioned that the acoustics of a domed shell has some properties that a flat plate can not compete with, thus domed tweeters.  It is this latter aspect that I think catalyzed the adoption of arched plates, in addition to the structural stability.

[Marty Kasprzyk]

1 hour ago, Don Noon said:

>

To be a bit nit-picky, only the A0 gets a significant boost from F-hole flow.  B modes are too high in frequency for the Helmholtz resonance to help, and most of the sound comes from the outer surface of the instrument. 

To what end goal?  More A0 and B mode power?  That can be achieved quite easily on a normal violin by making it thinner, yet that approach doesn't seem to be all the rage.  At higher frequencies, it has been mentioned that the acoustics of a domed shell has some properties that a flat plate can not compete with, thus domed tweeters.  It is this latter aspect that I think catalyzed the adoption of arched plates, in addition to the structural stability.

George Bissinger has shown most of the sound output below about 1000Hz is through the f holes as shown in his attached plot taken from his attached paper.

Flat panel speakers are common. You probably have one in your smart phone, computer screen or flat TV.  A domed tweeter isn't necessary which suggests the arching of violin plates isn't necessary either.

Violinf-holecontributiontofar-fieldradiationviapatch_2007.pdf

[Don Noon]

4 hours ago, Marty Kasprzyk said:

George Bissinger has shown most of the sound output below about 1000Hz is through the f holes as shown in his attached plot

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 .

 

[LCF]

23 hours ago, Marty Kasprzyk said:

Colin Gough has shown that when the bridge's vibrating force pushes down on the convex arched top plate that the top plate deforms with an out of plane movement which produces helpful volume changes but it also produces an in-plane motion which spreads out the top plate.

 

Marty I think those simplified diagrams don't include enough of the important details of how a violin top moves in the island area. The first consideration is the effect of sound post which stops the top under the treble foot moving much at lower frequencies and leverages the input motion towards the bass foot. Bass bar then communicates that asymmetrical motion to a larger area of the top and finally the ff holes excommunicate that island movement from the ribs, so as far as a cross section through the top near the bridge goes, if anything, the top is getting slightly narrower as the bridge drives downwards and the bending of the top is much more complex than a simple arch.

 

Incidentally I am no longer certain that the interaction betwen the A0 and B1+_ modes is anywhere near being  simple (violin joke : simple). Working through some modelling based on Schelling's ideas it seems that what we call A0  is lower than cavity resonance would be if the top was 'frozen stiff' under the bridge ie it might be partly an artefact of the interaction between the cavity reactance and the lower body resonances very similar to the guitar situation. 

 

 

 

[Marty Kasprzyk]

8 hours ago, LCF said:

 

Marty I think those simplified diagrams don't include enough of the important details of how a violin top moves in the island area. >

 

Colin Gough goes into great detail how the top moves in the island area in the attached report.

I believe the violin's spoundpost was another poor design choice made about 500 years ago.  Its offset positon is acoustically better than a central location because it forces the B1- node line to be also offset which makes the B1- mode shape to be asymmetrical which is beneficial. The bridge rocks back and forth piviting nearly over the sound post. When the bridge's bass foot pushes the top down on the left side of the top plate the plate on the right side goes up.

Due to the mode asymmetry a larger plate area is going down than is going up so the out of phase sound waves comming off of these areas don't completely cancel each other and some useful far field sound is produced.

Likewise the volume changes from these different area up and down plate movements don't exactly cancel so some air flow goes through the f holes and produce some useful sound.

But I believe the more ancient design of having the sound post going through a hole in the top plate was better with one foot of the bridge contacting it directly.  For example, consider the case if the bridge foot on the left is resting on the top plate and the bridge foot on right is resting directly on the sound post which goes through a hole in the plate.

When the bridge rocks back and forth and the left bridge foot goes down the entire plate area also goes down--there is no  out of phase cancellation of the sound waves coming off the plate or volume change cancellations reducing air flow through the f holes.

So the ancient design of having the sound post going through a hole in the top should have a better sound output than the more recent one having both bridge feet resting on the top plate.

But this is a highly biased supposition on my part--I've never seen anyone else's analytical or blind listing tests comparing the two designs.

The violin bridge-island input filter | The Journal of the Acoustical Society of America | AIP Publi.html

[LCF]

That's a great paper.  Fig 4 alone, modes of clamped  isolated bridge is enough to keep you pondering for a while.

 

Coincidentally at the Woodhouse site euphonics.org  the section on bridges and setups is currently being written and many interesting things are appearing there almost day by day. I think this goes much further than the ideas which were being discussed at the symposium on bridges.

 

https://euphonics.org/7-5-tonal-adjustment-in-the-violin/

 

All good stuff, 7.5, 7.51, 7.52, ...

 

Bridge symposium   https://youtu.be/ZFKOUkmx_U4?si=jrD_yw7vIzJ1veZy

 

Edited May 29 by LCF
Added link

[LCF]

1 hour ago, Marty Kasprzyk said:

... the ancient design of having the sound post going through a hole in the top should have a better sound output than the more recent one having both bridge feet resting on the top plate.

 

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.