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3 hours ago, Patrick KREIT said:

Szimon

 Based on the mode frequencies, the instrument should very good.

The signature mode frequencies and amplitudes look fine to me too.  However, if I took a spectrum that looked like that, I don't think it would sound very good due to the weakness from 1400 - 3500 Hz, a critical range for clarity, and the excessive strength over 4 kHz, often associated with harshness.  But that's with me using my equipment and method.  I have no way to know how comparable our results might be.  My guess is that the instrument isn't as bad as the spectrum appears to be (to me, anyway), and it's an artifact of the equipment, method, or tester.

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On April 30, 2017 at 6:41 AM, Peter K-G said:

I have been secretly copying Fjodor's latest violin and it looks like I got it about right. While waiting for the fittings and strings to arrive I have tracked the modes as the violin gain weight after varnishing. With a chinrest stable at 356 g. It's Plowden like with a strong B1- and less strong B1+

  A0 B1- B1+ B1-/B1+ Humidity
349 273 465 555 90 20 %
356 270 455 540 85 20 %

predicted values:

400 270 440 520 80 40 %

I notice that, for the B1+ mode, the frequencies are twice that of the A0 mode. Have you noticed this in other "good" violins of yours?  Is this one a "good" violin?

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13 minutes ago, Don Noon said:

The signature mode frequencies and amplitudes look fine to me too.  However, if I took a spectrum that looked like that, I don't think it would sound very good due to the weakness from 1400 - 3500 Hz, a critical range for clarity, and the excessive strength over 4 kHz, often associated with harshness.  But that's with me using my equipment and method.  I have no way to know how comparable our results might be.  My guess is that the instrument isn't as bad as the spectrum appears to be (to me, anyway), and it's an artifact of the equipment, method, or tester.

I agree. Measuring meaningful spectra isn't a skill-free operation. Can't just "hit and hope" without understanding what you're doing.

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Gentlemen - I am very grateful for your comments. Resonance study I started when I was doing instrument number 9 and for me the absolute discovery was the Patric Kreit website - thank you my Master for inspiration and knowledge!!! I am still learning and I love doing violin, because it is an investigation into the mystery of the intangible sound hidden in material wood - two absolute beauty. 
This screenshot is a measurement of a fresh, unadulterated instrument that has not yet touched the bow. Yesterday the first test at the concert hall - professional violinist played 20 minutes. The first sounds were exactly as wrote Don Noon (congratulations), but the sound was still "maturing", becoming more and more spatial, "3D". Particularly, the D string has changed noticeably. Now the violin is in the hands of great fidler (I can not play the violin at all) and will often be played. We will meet next Thursday, and we will make new measurements and tests with different bridges.
I am very curious your adventures with the process of "maturing" the instrument from the first sound to adulthood.
Next week a new FFT screenshot.
Thank You All 

Sorry for my English
Szymon - Poland, Poznań

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9 hours ago, Don Noon said:

The signature mode frequencies and amplitudes look fine to me too.  However, if I took a spectrum that looked like that, I don't think it would sound very good due to the weakness from 1400 - 3500 Hz, a critical range for clarity, and the excessive strength over 4 kHz, often associated with harshness.  But that's with me using my equipment and method.  I have no way to know how comparable our results might be.  My guess is that the instrument isn't as bad as the spectrum appears to be (to me, anyway), and it's an artifact of the equipment, method, or tester.

I too agree. It's a technique that is developed and learned with difficulty - much like learning how to play the instrument.

 

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Software is an indispensable tool for tuning the principle modes of the violin and all other stringed instruments, but can never give a response equal to the perceptions of the human ear.

A spectrum or sonogram reading for each half-tone on each string may appear to be identical to that of a Stradivari, but is unreliable and hardly reproducible. This depends on several factors: bow speed and pressure, recording equipment, the room, ambient humidity and moisture content
in the wood, mode frequencies of that given moment.

Correctly tuned mode frequencies ensure that the violin will be very good, but they never provide an exact indication of the instrument’s true acoustic qualities, which depend on the characteristics of the wood used, the quality of the work and the varnish. The instrument must be played by the violin maker and by a professional to have an objective point of view.

www.kreitpatrick.com

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18 hours ago, violins88 said:

I notice that, for the B1+ mode, the frequencies are twice that of the A0 mode. Have you noticed this in other "good" violins of yours?  Is this one a "good" violin?

The numbers are without settings. All my violins have a B1+ ~528 Hz when setup and normal conditions (~40-50% humidity)

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Szymon

The violin will be mature or "adult" once the back plate has reached its critical limit for deformation under pressure from the strings.

When the back plate becomes deformed, raising the B1+ mode frequency, you must sand at the center of the back plate of the violin set up in the white with its definitive chin rest (each chin rest lowers the B1+ mode frequency differently).

www.kreitpatrick.com

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3 hours ago, Patrick KREIT said:

Szymon

The violin will be mature or "adult" once the back plate has reached its critical limit for deformation under pressure from the strings.

When the back plate becomes deformed, raising the B1+ mode frequency, you must sand at the center of the back plate of the violin set up in the white with its definitive chin rest (each chin rest lowers the B1+ mode frequency differently).

www.kreitpatrick.com

Do I understand well - sanding in the middle should reduce the frequency of the back plate to get the modal results of the free back plate? 

The first hours of playing a new violin can perhaps be compared to breaking in a new car's engine - all the components need to align and adjust to one another. In my experience, the sound aspects of such an instrument improve with each hour of using it.

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5 hours ago, Szymon said:

The first hours of playing a new violin can perhaps be compared to breaking in a new car's engine - all the components need to align and adjust to one another. In my experience, the sound aspects of such an instrument improve with each hour of using it.

I believe it has more to do with the wood adjusting to the string stresses, although a bit of vibration from playing might accelerate the adjustment.

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4 hours ago, Don Noon said:

I believe it has more to do with the wood adjusting to the string stresses, although a bit of vibration from playing might accelerate the adjustment.

Yes, It is well known that the back plate will deform over time. We have seen a lot of CT scans of old violins ex. The Betts Strad

The first year (seasons; winter - summer - winter) is when the violin changes the most. If the back plate is too weak in the middle area and c- bout edges to begin with, the violin is a lost case because the "first year" deformation won't stop, even after 2-3 years, then it slows down but  B1+ has increased up to 25 Hz and B1- decreased. Their delta is way over 100 Hz and the violin has lost its focus and is hard to play.

If this is the case (too weak middle section) sanding the middle and c-bout edges is only helping temporarily and making the problem even worse later.

-> The violin is fire wood :) 

I have one it is the one tagged to this topic  Violin #5 - Strad Body modes. It does not have Strad body modes anymore

Right now without strings:

B1- 455 Hz

B1+ 575 Hz

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As I see - I have to call to current owners of the instruments that I did for them over the last few years. I'm afraid of what I can hear from them. I hope I do not have to do four back plates! I think I should probably do something safer. Does anyone have templates for ukulele? ;)

Edited by Szymon

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I think you are safe, after all the ones you have made are probalby good violins and work just fine. I'm working on the edge to get as close as possible to the goals I have set up for my self, that will say back plates closing 95 g

I did a mistake with Violin #5 because I was unexperienced and tried to tune a back plate that had undergone heat treatment and at 0% moisture content in the wood. That is practically impossible.

 

 

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I measure resonances from instrument No. 9 (2013). Results:

No       B1- / B1 + / delta
9        466  / 550  / 84
10      455  / 548  /103   (was built in 2014 - now in Denmark, now this can be the worst result)
11       466 / 555  / 89
12       455 / 534 / 79
13       443 / 534 / 91
14       456 / 544 / 88

These are the measurements of the new instruments. It would indeed be very informative to measure them now, but they are far from me. :( Unfortunately, in Poland the humidity is very variable, sometimes there are big differences between day and night. Besides, I have two moisture meters in the lab, but I do not know whom to believe to judge what the wood moisture is according to the table he gave on his website Patric Kreit.

DSC_4205.JPG.253eebe0fa36cea5a3897471fd4e0d69.JPG

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Szymon

95 Hz is the acceptable limit for the delta between modes B1- and B1+. At 103 Hz, it may still be workable; beyond that, there are no longer any mediums. The mode frequencies of your violins are appropriate; however, the moisture content in the wood is not known.

 

There are 2 important things you must know:

-Moisture content of the materials at the moment you make the frequency reading:

Thereafter, you can adjust the frequencies by a simple calculation of the percentage of the moisture content.

-Maximum height of the mode frequencies at 6% moisture content in the materials in the white or varnished and with a chin rest.

 

Great precision in the personal electronic weather station is not required. However, you must have a moisture meter for wood that is sufficiently reliable (classic or with scanner), for you absolutely must know what moisture content in the wood corresponds to the mode frequencies.  

Example with chin rest:

8% mode B1- 441 Hz mode B1+ 530 Hz delta 89 Hz

6% mode B1- 450 Hz mode B1+ 540 Hz delta 90 Hz

4% mode B1-  459 Hz mode B1+ 550 Hz delta 91 Hz

In the example with 4% MC, the mode frequencies are at the critical limit.

www.kreitpatrick.com

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11 minutes ago, Patrick KREIT said:

95 Hz is the acceptable limit for the delta between modes B1- and B1+. At 103 Hz, it may still be workable; beyond that, there are no longer any mediums. 

Here is an "unacceptable" violin of mine with the B1 delta at horrid 123 Hz.  I hope to make more that are this unacceptable.  #21

 

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1 hour ago, Don Noon said:

Here is an "unacceptable" violin of mine with the B1 delta at horrid 123 Hz.  I hope to make more that are this unacceptable.  #21

 

I think it sounds great. It would be interesting to know what the frequencies where unstrung, in some cases B1- can drop radically when set up (up to 35 Hz), because the top (and the soundpost, couldn't resist) moves down and the chin rest has an exceptional effect, happens often on light tops. M5 (top/back) - (346/362?)

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Here is a good violin B1- 435, B1+ 557 (d 122Hz)

WP_20160130_001.thumb.jpg.0a87e02e4523c9566d611f87dc4509c5.jpg

Here is the same violin 2 seconds later. The sound is the same, except for B & C notes are stronger) :

WP_20160130_004.thumb.jpg.885ed24327acc445409cd3ba92499ec5.jpg

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This is the sound of my instrument op.10 Delta 103 Hz - baroque gut strings. This instrument was chosen for the Royal Conservatory of Music in Copenhagen among seven other instruments. This is my greatest success. But I do not know how after 3 years these violins are playing if the delta is getting bigger.

 

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1 hour ago, Peter K-G said:

I think it sounds great. It would be interesting to know what the frequencies where unstrung...

I used to do that, but since I would never make any modifications without having it strung up and played first, it seems like an unnecessary measurement and I don't do it all the time.  I didn't on this one.

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As everyone on this forum knows, I do the opposite. Tracking and measuring everything, from start to the finished violin, very thoroughly. And I don't stop there but following their development over years as they mature. I have collected quite a big database.

Most of the misunderstandings is to think that the low body modes (A0, B1-, B+) produces a specific sound (kind of what I was trying to show with the previous post, same violin, different B1+ mode). It is the sound box as a unique unit that gives the base inherit sound and properties of a violin. How do you copy that?  The modes are reliable gauges only when the other floating parameters are known and mastered;

1. Wood properties

  • Determines the arching & limits of what type of violin you can make.
    • leads to a specific thickness for the woods density
    • leads to a specific weight
    • leads to a specific M5 frequency

2. Everything is floating according to the environment you are working in

  • Humidity and temperature

3. Wood properties - loop, decide what you want to do

Someone said, they all turn out different. I say they all turn out alike  i.e. - The Strad Sound

(Still small problem to overcome, I have never played one, so I'm copying my own for now (and Fjodor's latest ;)))

Have a great workshop day

Peter

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21 hours ago, Patrick KREIT said:

Szymon

95 Hz is the acceptable limit for the delta between modes B1- and B1+. At 103 Hz, it may still be workable; beyond that, there are no longer any mediums. The mode frequencies of your violins are appropriate; however, the moisture content in the wood is not known.

 

There are 2 important things you must know:

-Moisture content of the materials at the moment you make the frequency reading:

Thereafter, you can adjust the frequencies by a simple calculation of the percentage of the moisture content.

-Maximum height of the mode frequencies at 6% moisture content in the materials in the white or varnished and with a chin rest.

 

Great precision in the personal electronic weather station is not required. However, you must have a moisture meter for wood that is sufficiently reliable (classic or with scanner), for you absolutely must know what moisture content in the wood corresponds to the mode frequencies.  

Example with chin rest:

8% mode B1- 441 Hz mode B1+ 530 Hz delta 89 Hz

6% mode B1- 450 Hz mode B1+ 540 Hz delta 90 Hz

4% mode B1-  459 Hz mode B1+ 550 Hz delta 91 Hz

In the example with 4% MC, the mode frequencies are at the critical limit.

www.kreitpatrick.com

Thank you for your advice!

Something like that is enough? https://pl.aliexpress.com/wholesale?catId=0&initiative_id=SB_20170516080404&SearchText=moisture+meter+wood+scaner

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