Carl Stross Posted May 10, 2021 Report Share Posted May 10, 2021 54 minutes ago, Don Noon said: Some, perhaps... significant, no. I just performed a test: tuned, then D and A detuned to an octave low (~1/4 normal tension, I believe), and then back up to repeat the tuned state. A0 was 275 Hz in all conditions, as you might expect this mode to be least affected. B1- was 432, 428 detuned, and 415 tuned back up (the B1- in this instrument I think has two close peaks, and likely the lower one dominated when tuned back up). Repeating the re-tuned test: 433 Hz. B1+ was 545, 540 detuned, and 543 retuned. Repeating the re-tuned test: 536 Hz. So, OK, there are some frequency differences in the signature modes... but not much more than measurement scatter, and I would hardly call them significant. Far more significant is what goes on with the amplitudes, especially at the higher frequencies, and that changes much more. Throw into the mix the known transient (over days) effect that a change in static stress has on (primarily) damping, and you can a range of tonal effects... but I still think that the body mode frequencies stay essentially the same. I see. I was expecting aprox 15% difference and what you found is much, much less. Just in case you have it pinned down somewhere : have you described ( on MN ) how exactly you carry these tests ? Just to clarify : I do not see ( imagine... ) a reason for the freqs to stay close but not THAT close. Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted May 10, 2021 Report Share Posted May 10, 2021 If you ponder over,, how 15 lbs of air pressure can support thousands of pounds, and the pressure remains the same with or without the load applied...... Bingo ! or how to remove the resin from end grain, or maple flame after its been burned, it doesn't make sense it just is. Quote Link to comment Share on other sites More sharing options...
jezzupe Posted May 10, 2021 Report Share Posted May 10, 2021 4 minutes ago, Evan Smith said: If you ponder over,, how 15 lbs of air pressure can support thousands of pounds, and the pressure remains the same with or without the load applied...... Bingo ! or what weighs more a pound of gold or a pound of feathers Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted May 10, 2021 Report Share Posted May 10, 2021 1 minute ago, jezzupe said: or what weighs more a pound of gold or a pound of feathers Oh,,, Gold weighs a lot more,,, a whole lot more,, it weighs heavy in my pocket! Quote Link to comment Share on other sites More sharing options...
Carl Stross Posted May 10, 2021 Report Share Posted May 10, 2021 8 minutes ago, jezzupe said: or what weighs more a pound of gold or a pound of feathers Apparently, a pound of gold. I was told ages ago ( 86 or so ) that there was a very slight, irregular dependency of "weight" to density. I should've kept in touch with those things but music was much more interesting. Quote Link to comment Share on other sites More sharing options...
Marty Kasprzyk Posted May 10, 2021 Report Share Posted May 10, 2021 14 hours ago, violins88 said: I still think you should do the knock test and get the fft. Maybe there is change in the B1+, but maybe just not enough change to provide enough change in the wolf. Is a "knock test" the same as a "tap test"? My tap test is a fingernail tap to to the upper bridge edge on the bass side of my viola's bridge. I use Audacity software to get an fft curve. When I knock something it is usually a nearly empty beer glass with my right elbow. The sounds are quite similar. Quote Link to comment Share on other sites More sharing options...
Carl Stross Posted May 11, 2021 Report Share Posted May 11, 2021 9 hours ago, Evan Smith said: If you ponder over,, how 15 lbs of air pressure can support thousands of pounds, and the pressure remains the same with or without the load applied...... If you're talking about tires that's not true. It's just that the measurement is not accurate enough for the small differences. On one hand you have the elasticity of the tire and on the other the increase in contact patch transferring more of the load to the rim. Think those flimsy inflatable pillows : easy to burst one by stepping on it. Quote Link to comment Share on other sites More sharing options...
Peter K-G Posted May 11, 2021 Report Share Posted May 11, 2021 13 hours ago, Don Noon said: Some, perhaps... significant, no. I just performed a test: tuned, then D and A detuned to an octave low (~1/4 normal tension, I believe), and then back up to repeat the tuned state. A0 was 275 Hz in all conditions, as you might expect this mode to be least affected. B1- was 432, 428 detuned, and 415 tuned back up (the B1- in this instrument I think has two close peaks, and likely the lower one dominated when tuned back up). Repeating the re-tuned test: 433 Hz. B1+ was 545, 540 detuned, and 543 retuned. Repeating the re-tuned test: 536 Hz. So, OK, there are some frequency differences in the signature modes... but not much more than measurement scatter, and I would hardly call them significant. Far more significant is what goes on with the amplitudes, especially at the higher frequencies, and that changes much more. Throw into the mix the known transient (over days) effect that a change in static stress has on (primarily) damping, and you can a range of tonal effects... but I still think that the body mode frequencies stay essentially the same. I can confirm, this is how it goes. However, if you have a weak backplate middle section (especially near c-bout edges), over time it will deform. - Back increase in height and B1+ up to +15-20 Hz - Top decrease in height and B1- -10-15 Hz (more difficult to predict, depends on how it deforms) Quote Link to comment Share on other sites More sharing options...
bungling_amateur Posted May 11, 2021 Report Share Posted May 11, 2021 12 hours ago, Carl Stross said: Apparently, a pound of gold. I was told ages ago ( 86 or so ) that there was a very slight, irregular dependency of "weight" to density. I should've kept in touch with those things but music was much more interesting. A pound of gold is lighter than a pound of feathers: Gold is measured in troy pounds (5760 grains ≈ 373.24g), but feathers are weighed in avoirdupois pounds (7000 grains ≈ 453.59g). Now an ounce of gold is heavier than an ounce of feathers... Quote Link to comment Share on other sites More sharing options...
Jim Bress Posted May 11, 2021 Report Share Posted May 11, 2021 13 hours ago, Evan Smith said: Oh,,, Gold weighs a lot more,,, a whole lot more,, it weighs heavy in my pocket! Nope, gold weighs less because precious metals use the troy system that has 12 ounces per pound instead of 16 ounces per pound for everything else. Quote Link to comment Share on other sites More sharing options...
Carl Stross Posted May 11, 2021 Report Share Posted May 11, 2021 3 hours ago, bungling_amateur said: A pound of gold is lighter than a pound of feathers: Gold is measured in troy pounds (5760 grains ≈ 373.24g), but feathers are weighed in avoirdupois pounds (7000 grains ≈ 453.59g). Now an ounce of gold is heavier than an ounce of feathers... I thank you for the explanation but must confess I have no idea what you are ( so competently ) talking about. Quote Link to comment Share on other sites More sharing options...
Evan Smith Posted May 11, 2021 Report Share Posted May 11, 2021 9 hours ago, Carl Stross said: If you're talking about tires that's not true. It's just that the measurement is not accurate enough for the small differences. On one hand you have the elasticity of the tire and on the other the increase in contact patch transferring more of the load to the rim. . Yes,, I think it is true, from the perspective that the pressure in the tire doesn't know nor care that the load is placed upon it, because of the flexibility of the tire, and it's ability to adequately constrain the gaseous mixture contained therein, something my wife claims that I am unable to do. But she is wrong again, I am able if i want to. So the violin cares not about the strings placed upon it, the forces are all within it's ability to function with only slight deflections hear and there with not much measurable differences. Many years ago I though that I knew that there would be all kinds of measurable changes taking place, nothing is very obvious, wasted a lot of time looking, thinking there might be something down that road, there is not,, only static creep, slowly spreading the stress more evenly over time, hz's slowly migrate around and cycle back and forth with the weather. Something that Robert Zuger tries to point out, (how to make it happen faster in a more controlled manner),,only to get the shit kicked of of him, he is one tough hombre,, what a shame. I have made a number of violins with his arching, they can make a fantastic violin, as can, dasalo, strad, delgesu, testori,arching. If a person knows what they are doing almost anything with a bump can work nicely. I think Christian's new arching conceptual machine dynamic quantum box is fantastic! What do you think about it Carl? It really has possibilities, it will never sound exactly like an "old Italian but who cares? I have done similar concepts to guitars, with great results. The first time he put up a second clip of it was a bit over 3 minutes long, then he changed it,, parts of the first clip sounded a bit like the violin on my kruzwell,, a bit too clean,, But he's only just begun, I like the Idea. 9 hours ago, Carl Stross said: Think those flimsy inflatable pillows : easy to burst one by stepping on it. Yes, that would be like putting bass guitar strings tuned to fiddle pitch, on a fiddle thinned down to .5mm. carry on, it's good to see you around, just evan,,, blathering on. It surly would burst. Quote Link to comment Share on other sites More sharing options...
Don Noon Posted May 11, 2021 Report Share Posted May 11, 2021 Gold, feathers, air pressure, weight systems, tires, and inflatable pillows... are we going for a some kind of record of irrelevancy? Quote Link to comment Share on other sites More sharing options...
Carl Stross Posted May 11, 2021 Report Share Posted May 11, 2021 50 minutes ago, Don Noon said: Gold, feathers, air pressure, weight systems, tires, and inflatable pillows... are we going for a some kind of record of irrelevancy? What else is there.... ? Quote Link to comment Share on other sites More sharing options...
Carl Stross Posted May 11, 2021 Report Share Posted May 11, 2021 1 hour ago, Evan Smith said: 1. Yes,, I think it is true, from the perspective that the pressure in the tire doesn't know nor care that the load is placed upon it, because of the flexibility of the tire, and it's ability to adequately constrain the gaseous mixture contained therein, something my wife claims that I am unable to do. But she is wrong again, I am able if i want to. 2. So the violin cares not about the strings placed upon it, the forces are all within it's ability to function with only slight deflections hear and there with not much measurable differences. 3. Many years ago I though that I knew that there would be all kinds of measurable changes taking place, nothing is very obvious, wasted a lot of time looking, thinking there might be something down that road, there is not,, only static creep, slowly spreading the stress more evenly over time, hz's slowly migrate around and cycle back and forth with the weather. 4. Something that Robert Zuger tries to point out, (how to make it happen faster in a more controlled manner),,only to get the shit kicked of of him, he is one tough hombre,, what a shame. 5. I have made a number of violins with his arching, they can make a fantastic violin, as can, dasalo, strad, delgesu, testori,arching. If a person knows what they are doing almost anything with a bump can work nicely. 6. I think Christian's new arching conceptual machine dynamic quantum box is fantastic! What do you think about it Carl? 7. It really has possibilities, it will never sound exactly like an "old Italian but who cares? I have done similar concepts to guitars, with great results. The first time he put up a second clip of it was a bit over 3 minutes long, then he changed it,, parts of the first clip sounded a bit like the violin on my kruzwell,, a bit too clean,, But he's only just begun, I like the Idea. Yes, that would be like putting bass guitar strings tuned to fiddle pitch, on a fiddle thinned down to .5mm. 8. carry on, it's good to see you around, just evan,,, blathering on. It surly would burst. 1. Am not saying that a violin might not hide a similar behavior. I think it does. What I am saying is that there will be a small pressure increase as a real tire is placed under load. The increase is small because that's how the thing is made. 'xactly like a violin.... 2. Hard to say. Stiff, heavy strings - the old chromstahl of my childhood would wake up a stiff violin pretty nicely at the cost of horrible effort in playing. 3. I know the feeling. Some of those things are measurable but not with rudimentary tools such as FFT software and impact hammers. And then, there is the question of relating the measurements to "italian tone". That's be another cat... The statics surely matter but I am not sure how exactly, i.e. in which direction do they point. I've seen it going both ways as the stresses "equalized" : towards better and ...the other way. 4. He needs to associate / collaborate with somebody having a better command of the English tongue and capable of actually explaining things. He's not connecting his observations to specific tonal characteristics. 5. Yes. I've seen this more than once : arching which should not've worked actually does and does it very well. I've heard on YT one of your violins and it was right up there. Lacked nothing. 6. Might be. It did sound mildly "small" to me but that could well be the recording. I would've expected A BIT more character on G and would like the E to be slightly more shrill to work in a large hall. Again, the recording doesn't tell that much. But then, he's been at it for a long time and I'm pretty sure he knows what he's doing. 7. The $64k question... Everybody says it doesn't matter until they start comparing with say, Grumiaux playing the same thing. Then, suddenly it matters. Classical taste DOES change but slow. Very slow. You see this in Opera : present day soprano sings beautiful. Compared with the old warhorses, she's nowhere. Should we notice ? And if we notice should we discuss it ? I am not sure. 8. Thank you. Good to see you, too. All the best to yourself and the family ! Quote Link to comment Share on other sites More sharing options...
jezzupe Posted May 12, 2021 Report Share Posted May 12, 2021 6 hours ago, Carl Stross said: What else is there.... ? `Well we haven't discussed the role of the British pound in all this yet, but, I feel that if a chicken, covered in feathers, was concerned about air pressure and weights and measures that it could be worth it's weight in gold ,particularly if it wanted to sell at spot and then use that to buy one of Bayon's violins. Then people might think it a little more relevant, wouldn't they now. Quote Link to comment Share on other sites More sharing options...
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