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Violin #5 - Strad Body modes


Peter K-G

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Once again the formula worked. Intitial weight was 68 g. After cutting out f-holes 65,5 g

 

Frequencies before  f-holes

M2=161

M5=347

After

M2=143

M5=310

 

Graduation

B=2.1

D=2.3

C=3.5-3.7

A=3, soundpost area 3.3

Edges 2.6-2.8

 

post-37356-0-53096000-1367696854_thumb.jpg

 

 

 

 

 

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Once again the formula worked. Intitial weight was 68 g. After cutting out f-holes 65,5 g

 

Frequencies before  f-holes

M2=161

M5=347

After

M2=143

M5=310

 

Graduation

B=2.1

D=2.3

C=3.5-3.7

A=3, soundpost area 3.3

Edges 2.6-2.8

 

attachicon.gifTop_ff_cut.jpg

If the M5 returns to 347 when the bassbar is added, then Harris index is 4.23. Harris recommends 4.25. So you are close to his recommendation. John Masters' recommendation would be 0.79 and he recommends 0.8. So, again, you are close.

 

The Harris index is mass x (((M5 + M2)/2)^2/1,000,000)

 

The Masters index is mass x ((M5)^2)/10,000,000

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If the M5 returns to 347 when the bassbar is added, then Harris index is 4.23. Harris recommends 4.25. So you are close to his recommendation. John Masters' recommendation would be 0.79 and he recommends 0.8. So, again, you are close.

 

What does it measure two years later after being varnished, set up under tension  and played etc?

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If the M5 returns to 347 when the bassbar is added, then Harris index is 4.23. Harris recommends 4.25. So you are close to his recommendation. John Masters' recommendation would be 0.79 and he recommends 0.8. So, again, you are close.

 

The Harris index is mass x (((M5 + M2)/2)^2/1,000,000)

 

The Masters index is mass x ((M5)^2)/10,000,000

0.8 or 0.80 ? It's a big difference, you know ?

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The Cremonese makers apparently did not know about Harris or Masters stiffness recommendations, and therefore were all over the place.  The data comes from Curtin's article, and I added the info from this thread. 

attachicon.gifM5 vs wt.jpg

Don,

I think both Harris and Masters use plates with bassbar installed, don't they? Your data is for no bassbar.

 

It would be nice to have John Masters comment. I guess Harris doesn't do Maestronet.

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If the M5 returns to 347 when the bassbar is added, then Harris index is 4.23. Harris recommends 4.25. So you are close to his recommendation. John Masters' recommendation would be 0.79 and he recommends 0.8. So, again, you are close.

 

The Harris index is mass x (((M5 + M2)/2)^2/1,000,000)

 

The Masters index is mass x ((M5)^2)/10,000,000

M5 with bassbar will be 345 at 6% moister content in the wood.

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What does it measure two years later after being varnished, set up under tension  and played etc?

This I master :) by experiments with varnished and unvarnished plates over years winter/summer changes and UV box.

The top plate have been dried to 0% MC to test the highest frequency it's capable of. It will not go over that after varnished nor after years of use. In summer time it will be around 340 and i winter around 350.

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The Cremonese makers apparently did not know about Harris or Masters stiffness recommendations, and therefore were all over the place.  The data comes from Curtin's article, and I added the info from this thread. 

attachicon.gifM5 vs wt.jpg

I tried to be in the 61-63 region, where most of them are, didn't succed this time. But violin #6 is allraedy on the way :)

One thing to consider is that the cremonese has lost matter.

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Peter, re-reading this thread just now, my impression is that you are more interested in championing your conclusions and methods, than in learning and getting feedback. There's nothing wrong with that, along with striking off in your own direction, as long as you are consciously making that choice, and are aware of the limitations.

 

Maestronet is probably the best single public source of collective wisdom and expertise available today, so it might be most productive to rate the value of your own ideas, books you've read, videos you've watched, general woodworking wisdom etc. according to what you see here, rather than  evaluating Maestronet contributions according to how well they conform with outside sources of information.

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Well said David, it's my way of doing research.I'm very consistent when I try out something. The MN forum is definitely the best Place to do this! It's going better now also when I understand "readings between the lines".

 

David: my impression is that you are more interested in championing your conclusions and methods, than in learning and getting feedback

 

 

Hope I can adjust this because I'm very thankful for learning by feedback, I have made only 4 and a half violins:

 

Thanks to feedback I have learned a lot from posts in this topic for example:

 

http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-2#entry580814
http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-2#entry580837
http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-3#entry580915
http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-3#entry581342
http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-4#entry581420
http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-5#entry581931

 

Sorry if I have been too focused on objectives

 

I'm also trying the method against theese types of feedback:

http://www.maestronet.com/forum/index.php?/topic/327921-violin-5-strad-body-modes/page-6#entry585090

 

Please continue with feedback, I'm here to stay, as long as admin allows :)

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Don,

I think both Harris and Masters use plates with bassbar installed, don't they? Your data is for no bassbar.

 

The scatter gets even wider with the bass bar.  Again, from Curtin's Cremonese data:

post-25192-0-89877800-1367762859_thumb.jpg

Personally, I find that the unbarred plate taptone and mass are a better indicators of the character of the completed instrument.   But the relationship is only vague, and vastly different characters can be good or bad.

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The scatter gets even wider with the bass bar.  Again, from Curtin's Cremonese data:

attachicon.gifM5 vs wt barred.jpg

Personally, I find that the unbarred plate taptone and mass are a better indicators of the character of the completed instrument.   But the relationship is only vague, and vastly different characters can be good or bad.

For both the plots it seems as if the data lies along two "imaginary lines". Do you have any idea why we see this, or is it just by chance?

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For both the plots it seems as if the data lies along two "imaginary lines". Do you have any idea why we see this, or is it just by chance?

Those two "imaginary lines" are approximately on a "same plate slope" (I just made that up):  where if you take a plate, and continue to thin it down uniformly, the weight and taptone will decrease together to keep you on that line.  I would speculate that the two lines could indicate two sources of spruce with significantly different properties.  I have heard one of the instruments on the lower line in person, a Strad, played against several other violins... it wasn't very impressive.

 

There are other possibilities, such as different plate size, arching, or graduation concept, that naturally could affect the frequency/weight ratio.

 

edit:  perhaps it means nothing, but it is an interesting coincidence that the three "lower line" instruments have dates of 1726, 1727, and 1728.  The upper line instruments: 1685, 1700, 1716, 1730, 1762, and one undated.

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The Cremonese makers apparently did not know about Harris or Masters stiffness recommendations, and therefore were all over the place.  The data comes from Curtin's article, and I added the info from this thread. 

attachicon.gifM5 vs wt.jpg

Don,

I don't know where to find the Curtin article right now. Are ALL the violins on this table great sounding violins, or simply old Cremonese? 

Thanks

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You can find the article on Joseph Curtin's website, along with a bunch of other good articles.  The taptone article is http://www.josephcurtinstudios.com/images/StradTapTones.pdf

 

You wouldn't expect there to be "ratings" of whether they sound good or not, and there aren't.  In personal conversations with him, I gathered that there weren't any stinkers in the group.  The Strad that I thought was unimpressive wasn't a stinker, but definitely not outstanding.

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