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Nick Allen

What to do with spongy American spruce?

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1 hour ago, JohnCockburn said:

Thank you for taking the trouble to give a detailed explanation, Marty.

Agreed... that way I don't have to do it (and I didn't feel like doing it anyway).

As complicated as all of that is, it's incomplete as it doesn't evaluate the player and bow effects.  It's really more complicated.

Or, as Marty suggested, you can simplify by just making violins.

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20 hours ago, Marty Kasprzyk said:

Going back again to Benade's graph we see that this 1.33 admittance ratio should give us about 2dB increase in sound output.  So going from lousy 12RR wood to great 16RR wood gives you just a small improvement in sound output.

2 dB should be clearly noticeable. Taking into account that the difference between good and great violins isn’t all that huge, using good AND high RR wood is a rather easy step in order to improve the violin quality.

BTW, in Picea abies a RR of 12 isn’t that far from average.

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On 1/15/2020 at 8:23 PM, David Beard said:

Going back to the OP, and not to be flip, but my feeling is you should stick to wood you positively like, not try to figure out how to adjust and accomdate wood that you describe in a negative way, like spongy.

  I personally would try using what he has for wood.  Nobody uses worse wood than myself - what I'm not sure about with the o.p.'s case is what did he use for back plate wood and grads, how he went about making a neck, blocks, bass bar, fingerboard tolerances along with neck set, hard or soft varnish and I heard he used something similar to Strad arching - whatever those may be.  Has the o.p. been able to study master grade instruments? I think he has but I'm not sure.

  All I'm saying is I could make his wood work well but it would take experimenting by making minimum changes throughout each build as compared to the build before.  

  I'm assuming he bought a load of that stuff instead of just three or four wedges.

On a side note - there's always the Evan technique - you just keep taking the fiddle apart until one gets ideal results, if possible.

Go Chiefs!  

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2 hours ago, JohnCockburn said:

Thank you for taking the trouble to give a detailed explanation, Marty.

Yep, it was a good read through.  One question though.  Is the upside down v supposed to mean multiply?  I can't remember.

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On 1/16/2020 at 11:52 PM, Advocatus Diaboli said:

Marty, how do you feel like the player/bow play into this?  In my experience, the theoretical 2db scenario will make a violin that's quite loud under the ear and responds very well to light bowing, but bottoms out easily.  Medium or lower RR wood ends up making an instrument that takes a heavier bow arm and ends up sounding louder.  Does that line up with the math at all?

!!!

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2 hours ago, uncle duke said:

Yep, it was a good read through.  One question though.  Is the upside down v supposed to mean multiply?  I can't remember.

it means "raised to the power of", so x^2 means x squared, x^3 x cubed and so on.

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On 1/17/2020 at 2:52 AM, Advocatus Diaboli said:

Marty, how do you feel like the player/bow play into this?  In my experience, the theoretical 2db scenario will make a violin that's quite loud under the ear and responds very well to light bowing, but bottoms out easily.  Medium or lower RR wood ends up making an instrument that takes a heavier bow arm and ends up sounding louder.  Does that line up with the math at all?

Thanks. This is a serious question for makers and players and I'll address it in a few days.

But I make lot's of mistakes so I worry about leading people astray.  Doug Martin has been an inspiration to me and he said:

"I love it when my most cherished beliefs are proven wrong."

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On 1/17/2020 at 2:52 AM, Advocatus Diaboli said:

Marty, how do you feel like the player/bow play into this?  In my experience, the theoretical 2db scenario will make a violin that's quite loud under the ear and responds very well to light bowing, but bottoms out easily.  Medium or lower RR wood ends up making an instrument that takes a heavier bow arm and ends up sounding louder.  Does that line up with the math at all?

I think I recall Michael Darnton mentioned a long time ago that violins with light and thin tops often had an "on-off" characteristic.  These couldn't get range of middle loudness or color so the sound couldn't be molded much and were therefore had a only a limited range of expression available for a good player.

I believe Mr. Darnton recommended using thicker plates. Hopefully he will address this again for us.

I wrote the  attached pdf to show how thicker plates might be helpful for eliminating "bottoming out"  which references an article, also attached,  giving a math background addressing wolf notes.

 

 

 

Bottoming out, pdf.pdf wolf notes, Woodhouse .pdf

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On 2/3/2020 at 12:57 PM, Marty Kasprzyk said:

I think I recall Michael Darnton mentioned a long time ago that violins with light and thin tops often had an "on-off" characteristic.  These couldn't get range of middle loudness or color so the sound couldn't be molded much and were therefore had a only a limited range of expression available for a good player.

I believe Mr. Darnton recommended using thicker plates. Hopefully he will address this again for us.

I wrote the  attached pdf to show how thicker plates might be helpful for eliminating "bottoming out"  which references an article, also attached,  giving a math background addressing wolf notes.

 

 

 

Bottoming out, pdf.pdf 851.02 kB · 15 downloads wolf notes, Woodhouse .pdf 988.11 kB · 9 downloads

Thanks!!

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On 1/13/2020 at 11:08 PM, Nick Allen said:

 The signature modes seem to be high, though. But I don't know if I can trust those figures as I still don't have a firm grasp on the process. 

Here's a m5 squared x plate weight formula for stiffness index that was originally used for a special pile of wood Mr. Masters once had for use.  

Once you find what your wood wants to do you could keep track of figures using aformentioned formula.

I was told that 14,000,000 is a maple back plate figure to shoot for and that works well during the process of working down to 109 grams, imo.  Example  360 hz x 360 hz x 129 grams = 16,718,400 - I'd keep going to get closer to 14,000,000 while others may stop there.   

8,000,000 is the belly figure to shoot for but keep in mind this number was for John's special batch of wood he had at the time.  We have no idea about his arching scheme or height or everything else in regards to his wood.  I've found maybe going lower than 8,000,000 can be o.k. but I'll admit I'm still searching for the "correct" belly heights and widths.  I sorta know what I want for arching.

I've heard 6,000,000 can be a figure to work for for spruce but that figure may be from another formula.

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Marty,

The bow force diagrams and calculations all pertain to "at a given bow speed"... which naturally leads to the question of how bow speed influences the situation.

Now if you could just analyze everything for about a dozen different bow speeds and plot the results, then we'd have the whole picture in all its complexity.  And we'd have no idea what to do with it.

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On 2/7/2020 at 9:24 AM, Don Noon said:

Marty,

The bow force diagrams and calculations all pertain to "at a given bow speed"... which naturally leads to the question of how bow speed influences the situation.

Now if you could just analyze everything for about a dozen different bow speeds and plot the results, then we'd have the whole picture in all its complexity.  And we'd have no idea what to do with it.

One way for making a violin capable of being played close to the bridge and also not having bad wolf notes is to make it with a high impedance (stiff, heavy plates and bridges) and use low impedance strings on it (low tension, low mass).  

A large impedance mismatch reduces the rate of energy transfer from the string's vibration into the violin which reduces the amplitude of the violin's vibration which in turn doesn't make the bridge vibrate much which in turn allows the string to vibrate correctly when bowed which in turn makes the playing sound good.

It took me a long time to understand why my violins with light plates and heavy tension strings were loud but so difficult to play.

 

Paraphrasing John Belushi:   "Seven years down the drain!"

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