Arch Symmetry vs tone

[Regis]

I'm interested in how crucial the top and back arching symmetry is (in relation to tone, not appearance).

Another way to ask this:

If I've cut the long and all the cross arches down to the templates, then take the rest down. How important is "exactly" mirroring the transitions?

Is the smoothness of the transition and graduation of each (top and back) a lot more important than matching the top & back arching precisely? In reference to tone.

Thanks,

Regis

[Oded Kishony]

There is often significant asymetry in arching, model and graduations in some of the greatest sounding insruments around.

Oded Kishony

[MANFIO]

Well, some instruments have suffered distortion and the archings given in the posters reflect them. I think that in general only the tranversal arching guides are used, if you try to use the long arch and the transversal archings you will note they will never match. Try to follow the concept of the origal.

[Jacob]

I'm not sure that the top and back archings are always supposed to be the same.

What Manfio says is true - to get the "concept" right rather than trying to match a set of arching templates exactly. That's one of the reasons why playing around with curtate cycloids is such a hot topic these days.

[AMORI]

Both books that I learned from have indicated that the front and back archings should have different heights. That means the curves will be slightly different too. I must say that I have made mine more or less the same as each other so far. Maybe the actual smoothness of the transitions are more important?

[Jacob]

I don't know - some archings seem smoother than others. Whether that is actually important (tonally) in the sense of being good or bad I doubt.

[AMORI]

I think the smoothness (and exact shape) is quite important. That is, based on my limited experience. I have experimented with alernative shapes.

What I'm not sure about are the exact height requirements. Anyone know? I think it was 16 mm for the front and say, 15 mm for the back?

[Oded Kishony]

The violin is really a very forgiving structure. Look at how different the Brescian arch is from the Cremonese, how different Strad's arch is from DelGesu. Within a range, variations can work very well. The reason is because the violin derives is sound qualities from a variety of factors, arching being one, albeit an important one. The other side of this coin is that I've also seen very well made instruments that for some inexplicable reason sounded awful, but these are much more the exception.

Oded Kishony

[AMORI]

One of the shapes I tried was sort of "pinched". That is a gentle rise to start with but because I had to reach the full height the slope had to climb quickly near the centre of the plates. The sound of that violin was "pinched" and a bit nasal.

[Regis]

So, I'm taking from this discussion that I should just set some cross arches and then concentrate on smooth flow/transition from area to area and peak to edge on each plate independantly. I should not invest time into matching the plates. And as long as my top and back are within the range of 15-16mm each, I'm ok??

Then, I have to ask, how do you go about improving the arch on subsequent violins for better(?) tone? Do you alter the arching of only one plate?

[Craig Tucker]

You're right, the violin IS very forgiving in this regard.

You can detect from various peoples conversation that they may think that perhaps some sort of design information is being kept back by makers in general as either "secret" or a "trade secret" regarding thicknessing and/or arching.

The fact is, though, that many different combinations of thicknessing and arching work well together. One can pretty well conceive and execute a workable combination of ones own conception because there are no hard and fast rules governing this area of making, other than those that are continually spoken of.

I think this is where many inexperienced makers get confused.

If there were such information, it would have emerged by now and have become part of the generally held public opinion relating to violin making. As it stands, the information that exists regarding these things is sufficient to the task with no additional clarification. Anyone seeking to make violins today has only to look into the matter and when they end up actually making them, (them meaning violins) then common sense will dictate the minutia involved in arching and thicknessing, and experience will reveal those things that seem mysterious, confusing or unexplainable at the start.

In addition, I'm not sure that a strict adherence to symmetry IS key to producing a good tone. I work towards symmetry, but don't use arching templates or worry overly much about producing EXACT mirror image arches or outlines - it isn't really that important, especially as regards the tone of the instrument. Whereas the tone may well be dependant on the string pressure being exactly right, that is in an entirely different realm as the odd outline irregularity.

Studying the old masters violins in order to understand what's going on will yield useful information in many areas, but not necessarily the information that one would expect.

A good current example would be the conversation we had here recently about graduating a Strad model violin down to a thickness of 2mm over the top plate.

Perhaps Strad graduated the original violin down to that thickness (which I doubt) and perhaps it lost the wood over the centuries, but copying that thickness today in an attempt to get the same results as the violin in question doesn't work. Looking towards the old masters arching in order to determine EXACTLY what our own arching should be today is similarly a losing proposition.

[Regis]

Thanks CT,

I started this because I caught myself spending a lot of time (and frustration) trying to match the top and back arch. Then I asked myself "why?".

Thanks to all,

Regis

[Oded Kishony]

Regis,

>Then, I have to ask, how do you go about improving the arch on subsequent violins for better(?) tone? Do you alter the arching of only one plate? <

Carrying out valid experiments on violins is really tricky. If you are trying to determine how changing the arching will affect the sound, then building a new violin with different top arching will not be conclusive at all, because it's a different back, neck, ribs, bridge etc etc. In my mind, the best way to experiment is to make a new/different top for the same instrument, using wood from the same tree, with the same density and elasticity then decide which elements you're going to change. The more elements you change the more difficult it is to know which had the greatest effect. You can compare the sound before and after,. I often use a 'reference instrument' and note that violin 1 is brighter on the G string than violin 2 etc. Or you could try recording the two instruments, so you can hear them side by side.

Oded Kishony

[Claire Curtis]

(Re: 'giving up' on making the top and back arches identical)

The violin is not just a piece of equipment, it is also a piece of art. A finely carved scroll (vs crude workmanship; I'm not getting into distribution of mass) probably has no affect on the tone of the instrument, but will greatly affect the evaluation of the instrument as a work of art.

I don't think _matching_ the front and back arch means to make them identical. It's more that they should be in keeping with each other. Imagine the front and back fenders of a car -- they are different in shape, but part of a coherent design. If you replace a fender with one from a different model car, it sticks out like a sore thumb. It no longer appeals to one's aesthetics.

My teacher used to say things like "the curve of the scroll should reflect the long arch going into the corners" -- it took a long time to make sense of that. The curves aren't identical at all, but they should be part of a consistent design. That is part of the 'art' component of the violin.

Of course, none of this addresses the original question of symmetry vs tone. I'll point out, though, that there are a lot of cut-away and wildly asymmetric violas out there, and the tone seems to be acceptable. In any case, I was taught that the long arches should _not_ be the same on front and back; the top swells out faster (under the fingerboard) than the back.

Just FYI, here's an old article (1999) on asymmetric graduation:

http://www.scavm.com/Lively.html

I haven't tried this procedure, but it may be of interest.

-Claire

[Jacob]

"I think the smoothness (and exact shape) is quite important."

If this were so, regarding the "smoothness", then generally del Gesu's should sound/work better than Strads - do they?

Regarding "exact shape" - again taking Strad as an example, we then have a maker who stumbled on many hundreds of different "exact" shapes which all work.

Don't you find that a bit hard to chew on, as opposed to a few different "general" approaches to an essentially basic arching philosophy?