A0 mode: What is more important air mass or frequency?

[Peter K-G]

2 hours ago, uncle duke said:

After noticing your 45 sg. Soil belly example that you are planning to take apart I must ask are any of the other nine what one could call exceptional to where you wouldn't want to change anything?

The reason I'm asking is if there happens to be an exceptional example we could apply the " MK plate hz correction formula " to the violins that need to be adjusted and make them the same or as close to the exceptional example as possible. 

It would be nice to have plate weights and free plate hz information in advance assuming all wood for back and bellies are the same spec wise.  

 

I'm only at the 5th copy. Business is taking too much of my workshop time.

They are all, in my own opinion (and some other makers and players) fine violins. I'm not opening it becauce it's bad. I'm opening it for research.

Sorry to have no idea about what "MK plate/hz correction formula" is.

All tops are 350 Hz varnished and 68-70g, densities vary from 0.4 - 0.5.

All backs 350 Hz varnished and 98-100g, densities vary from 0.56 - 0.63 

 

So I think if you put a formula on them, they would have the same result

 

[Anders Buen]

28 minutes ago, Peter K-G said:

I'm only at the 5th copy. Business is taking too much of my workshop time.

They are all, in my own opinion (and some other makers and players) fine violins. I'm not opening it becauce it's bad. I'm opening it for research.

Sorry to have no idea about what "MK plate/hz correction formula" is.

All tops are 350 Hz varnished and 68-70g, densities vary from 0.4 - 0.5. So I think if you put a formula on them, they would have the same result

According to my regression studies (including some data from you), mode 2 is a better predictor for the B1 modes than mode 5. 

[uncle duke]

You are the only maker that I remember having a lot of wood that was physically the same.  I didn't really expect you to pay heed but since you are at #5 out of ten, hmm maybe.

Anyway, when I was learning about wood removal for bellies and backs I was given a few formulas, probably untested in use, to help with what could possibly help with learning better.

The first suggestion was i=fm with i meaning impedance.  Afterwards match plates together to see what could or would work for future patterns.  For me it didn't get a chance to work because I had already had the boxes glued together before the impedance formula was given.

Now this plate correction method is for heavier than preferred 65 gr. and 109 gr. plates where m5 hz was low enough but overall weight is still to much.

So the suggestion/example can be to figure out the unneeded weight from a prefered 65 gr. and then multiply that unneeded weight by 32/24 for a belly and 19/24 for a back [109 gr.].  The answer would be where the plate should be hz wise. 

Sounds good and all but i never got chance to put it into the practice of wasting a few plates, which has to happen, I think.  

 

[Peter K-G]

16 minutes ago, Anders Buen said:

According to my regression studies (including some data from you), mode 2 is a better predictor for the B1 modes than mode 5. 

That can't be excluded, if doing real research all parameters should be taken into account. I find it more of a combinations of several of parameters. 

If you make plates ala hutchin tuning and force the plates to 350 Hz, there is no correlation between free plate and B1 modes. Mass in the middle section is important.

The thicknesses (especially in the middle, where M2 is sensitive) is critical.

The two latest tops of Finnish spruce turned out low in M2, that seams to be the nature of our trees here. strong lengthwise but weak cross grain. The B1 modes are the same though.

[Andreas Preuss]

5 hours ago, Anders Buen said:

According to my regression studies (including some data from you), mode 2 is a better predictor for the B1 modes than mode 5. 

This thread is a kind of getting ‘in the modes’.

Thats a quite interesting statement. When I was still more focusing on free plate mode frequencies I came over the time more and more to the conclusion that mode 2 is more important than mode 5.

And during my experiments on the new concept violin I had some major improvements by stabilizing the cross stiffness of the instrument.

[Don Noon]

9 hours ago, Anders Buen said:

According to my regression studies..., mode 2 is a better predictor for the B1 modes than mode 5. 

According to my data, assuming a fixed value for the B1 modes is about as accurate as using plate modes for predictions... although I know that for a given instrument, thinning the plates reduces plate and body modes (usually), so there is some vague connection.  But to me it's all mostly academic; the frequencies don't seem to be all that critical.

[Peter K-G]

1 hour ago, Don Noon said:

According to my data, assuming a fixed value for the B1 modes is about as accurate as using plate modes for predictions... although I know that for a given instrument, thinning the plates reduces plate and body modes (usually), so there is some vague connection.  But to me it's all mostly academic; the frequencies don't seem to be all that critical.

The frequencies critical to what?

[Don Noon]

7 hours ago, Peter K-G said:

The frequencies critical to what?

Signature mode frequencies don't determine if something is good or bad, as long as they fall within reasonable (and fairly wide) bounds, which they naturally do as long as you don't do anything too outlandish.  If you believe otherwise, please provide proof.  There might be some individual preferences for modes in a certain spot, I suppose, but I don't see that it is a common thing.

Amplitudes are a different and much more important issue, but still not nearly as important as all of the stuff above the signature mode frequencies.

[Peter K-G]

21 minutes ago, Don Noon said:

Signature mode frequencies don't determine if something is good or bad, as long as they fall within reasonable (and fairly wide) bounds, which they naturally do as long as you don't do anything too outlandish.  If you believe otherwise, please provide proof.  There might be some individual preferences for modes in a certain spot, I suppose, but I don't see that it is a common thing.

Amplitudes are a different and much more important issue, but still not nearly as important as all of the stuff above the signature mode frequencies.

Fortunately your answer is the same as usual

I almost was affraid you would give a different answer this time.

[sospiri]

9 minutes ago, Peter K-G said:

Fortunately your answer is the same as usual

I almost was affraid you would give a different answer this time.

You want him to agree with your beliefs?

This whole thread is stacked with delusional nonsense. You can't design the harmonically perfect violin. Such a thing is beyond the laws of physics.

 

[Peter K-G]

..aand now you're grounded, no speaking when grown up discusses important stuff...

 

Don and I always agree, we just confirmed that signature modes aren't a definition of good or bad.

[sospiri]

1 hour ago, Peter K-G said:

..aand now you're grounded, no speaking when grown up discusses important stuff...

Did I miss something important? 

Did you find a way to square the circle?

 

[Anders Buen]

The levels of the signature modes (and the other regions too) does matter and is part of what Joe show now after tests of the instruments being subjected to double blind listening tests against some fine del Gesus and Stads, or one of each.

This is in agreement with common belief and knowledge in room acoustics and other subjective tests: Loudness is important. 

Saunders knew this (he worked with Heifetz in the 30ties and 40ties) Meinel (pre WWII) and maybe after. Jesus A Moral came to that conclusion in his PhD work where the ran statistics on measurements from rated violins from a competition, under Jansson.