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basic plate tweak question

 
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jethro
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PostPosted: Tue Oct 04, 2016 1:38 am    Post subject: basic plate tweak question Reply with quote

Hi all.... getting back into my violinmaking after ignoring for 3 or 4 years
(shame on me---yes)
My 2-nd violin I used strobels graduation diagram on the plates. i got them
probably within about .004 inches. That was maybe useless (?) possibly because of invisible variations in wood density and stiffness.
with some repeated thinning of the back plate i was able to hit the specified
mode frequencies durring the tea leaves test. light ground of either jello or dilute glue ( I forget) Then about 9 coats of oil varnish with french polishing
between coats.

Final result is a very loud violin. Kind os obnoxiously loud with most of the
louder types of strings. After multiple string experiments-- i found violinos
tamed the vollume down the best. helicores were next best- a bit louder.
Had a bit of wolfing on A string but that has calmed down over time.

I had pretty rigidly followed Strobels topo map for top and bottom......
I feel like the plates are TOO acousticly active ---- that is they are some
how too close to resonance (conceptualy speaking--- like they are over driven--- )

If I think of the plate being a spring-mass........ and I immagine the center 80% of the plate as the mass and the borders arround the edges
as the "spring"..... (unless its really the other way arround...)
then I SEEMS like if I need slightly less response-- or more damping--
(dont know if those happen for the same change or 2 different changes)
or both....... I still want to hit my mode frequencies- (right?)
if I make the spring area (the perrimeter areas) thicker to cause less
flex and less amplitude of the center mass area... that should raise the
plate frequency ----- so to lower it back down It would seem that the
center of the plate (the "mass") needs to be heavier.....

That would seem to mean slightly thicker everywhere all over the plate....
Does that sound right ? Would this indicate my wood had a higher
stiffness to weight ratio than strobels- so mine was too thin for the frequency--- and more efficient at vibrating (maybe too much so)

The sound seems loud but not "interesting" or colored. (G and D are
full and powerfull and warm but A and E are kind of more one dimentional sounding- but also loud.

i have cut the outside shapes of the current plates and gotten the purfling done..... so more or less (unless i adjust the outside more) the inside hollowing would be next........

So to all of you who are doing this al the time---- is there a clear path to be taken to get the desired result ? Is it just making it thicker ?
I believe I am missing something conceptualy- because i thinned the inside down very gradually - measuring the mode frequencys often as i went. Dont want to duplicate the same error again !

Thanks ahead of time for any wisdom from the experienced.....
Tim
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Dave Chandler
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PostPosted: Tue Oct 04, 2016 4:43 pm    Post subject: Reply with quote

First off, I can't make sense of whether you're talking about #2 which is loud, or theoretical questions for #3.

If you're talking about a completed violin too loud, I'd start by putting the soundpost closer to the feet of the bridge, should tone everything a bit and make sweeter. Make sure post is straight up and down. A good place to start anyway.

Stringlength, afterlength, height of saddle, weight of fingerboard, etc.

I'm thinking if all else went by the plan, setup should be able to take care of the rest.
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jethro
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Posts: 178

PostPosted: Tue Oct 04, 2016 11:04 pm    Post subject: Reply with quote

thanks for the reply Dave.....
I am referring to both.....
Violin #2 has been done for about 4 years and being played.
I am about to do the thicknessing on #3's plates.
#2 is too loud and not as rich a sound as I think it should be.
( I have been told by professional players that it would fit the playing style
of stage bluegrass players more than classical -- due to huge volume and
kind of "plane" sound.

I don't want to just duplicate #2 and have another too loud instrument.
I have gradually done all of the normal adjustments you mentioned---
which helped in its response and feel--- but never lowered the volume.
I have been "all over" with the bridge and post multiple times and even
had a long time luthier set it up too.

so the question comes down as to how to change the graduation to get
less "amplitude" ----- and still hit the mode frequencies for the plates.
Just looking for a "general approach" as to how to proceed.

Don't want to make the same mistake twice.....
The instrument came out very beautiful..... FWIW

Tim
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Michael Darnton
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PostPosted: Wed Oct 05, 2016 8:03 am    Post subject: Reply with quote

Just a check here: it seems like you don't want a modern-type violin, fast, loud and monchromatic, but you are doing everything possible to achieve exactly that sound. Why not try working like the people who made the type of violin you do like, 300 years ago, and let go of all that precision and tuning--rather than make a violin that is so well co-ordinated that it dumps everything in your lap all at once, make one that resists just a bit, holds back a bit, so that you get to pick and choose the volume and tonal quality you want.

What you have there is a one-speed blender with an on/off switch, and you aren't going to make it more subtle by making a better switch and faster motor.
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ctviolin
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PostPosted: Wed Oct 05, 2016 1:18 pm    Post subject: Re: basic plate tweak question Reply with quote

jethro wrote:
Hi all.... getting back into my violinmaking after ignoring for 3 or 4 years
(shame on me---yes)
My 2-nd violin I used strobels graduation diagram on the plates.

Thanks ahead of time for any wisdom from the experienced.....
Tim


Also of interest is what type of wood did you use?

Are you using Domestic woods or European woods for the top plate?
Just curious.
I've used domestic Sitka, and domestic domestic Englemann spruce, and European spruce (early on) for the top plates, and have found them to be extremely different in want of proper thickening.
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rs
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Location: Holland, Michigan

PostPosted: Wed Oct 05, 2016 3:12 pm    Post subject: Reply with quote

I have done a lot of trial and error stuff to make violins. Two things I will throw into the mix:

The first is for the past couple of years, I have concentrated on backs with cycloids in all directions from the center. The long arch, the transverse arches and the diagonal arches. The cycloid diagonal arches gave my instruments more dynamo. I then applied the same principle to the inside and cut the back out with male cycloid templates. This incidentally gives the back grads that are slightly thinner inside the scoop and fans out over the scoop to the edges. I found this gave my instruments more dynamo still and might (emphasis on might) have been a method used by the ancient makers. As the extant instruments have been re-worked on the inside by people using calipers and such later on, there is no way to test or prove that idea. I just found it works well for me and is a logical possibility for what the forerunners might have done (emphasis on might and possibility). I don't pay attention to grads, tuning or any of that stuff. Players could not care less what the tap tone of a plate is, they want something fun to play and easy to get what they want out of it. That's true of student players as well. If I can make a violin that fits those needs of the player, my job is done and his or her job is just beginning.

The second is the top. I don't use calipers anymore for the top either. I simply use a punch and get everything down to about 3.2 mm or so and then a light shining through to get it a little thinner in the center than the edges. The center is then a brighter pink. The top ends up about 2.8, 2.7 or so in the center and slightly fans out. Again, I get more dynamo from the instrument this way.

The only measurements I am strict about have to do with feel and playability. The strings must be spaced apart exactly every time, be off the board the exact distance top and bottom with a little more flexibility in the scoop of the board. The nut must be 130 mm from the top edge and the stop length 328-330 mm. All the rest of the measurements kind of fall in line after that. These string set-up measurements are important because they are important to the player, not necessarily to performance.

I made the cycloid calculations by drafting a model and using arc segment calculations to get the radii needed. I get better results with arches that are about 14-15 mm than the taller 16 mm on up ones, but that might just be me. The cycloids calculate better with the arch at about 14-15 especially when making the diagonal ones. These are flatter measurements than most moderns, but appear to me to be more in line with the ancients.

If I were to emphasize any of the above information, it would be the value of diagonal cycloid templates as well as the usual cycloids for the transverse and long arches only. With careful layout, the calculations work and can be implemented into the diagonals.
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jethro
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PostPosted: Thu Oct 06, 2016 2:20 am    Post subject: lots of stuff to think about ! Reply with quote

MD: Ok- I think you made a flash bulb go off in my brain...... I believe you are correct--- perhaps the extreme brightness was just what the
"formula" produced--- and probably some slight ignorant unintentional
variation caused a slight unpleasant "edge" to the tone.

The first violin I followed a beginners book I bought at woodcraft--- written
from the point of view of a fine wood worker-- not a luthier. Written by
Bruce Ossman He had a completely different grad map- all most opposite of Strobels. Ossman's was thick at the
edges and had a gradual taper to the central area. It seemed to have a much more quaint sound with more character. everybody liked the sound
better than the 2-nd politicaly correct very loud one. #1 was definitely
a country-looking fiddle...... where # 2 was supposed to be a regulation
classical orchestral type instrument--- as perfect as possible in every way.

#2 was made with highly flamed maple back and good quality engelman spruce. ebony fingerboard. Came out very beautiful.

#1 ---- I made the top from a 14 inch wide board I found at Lowes. I searched through hundreds of boards till I found one with near perfect quarter cut and about 1 mm grain width. It actually had flame figure!
It was a 14 inch wide by 14 foot long. The center of the tree was exactly
centered down the center of the board. (nobody wants those boards for construction as they snap in two so easily down the middle) I cut out two pieces down one
side which just about matched each other once joined. Back plate was just a low figure inexpensive blank from IVS. Bouts were made from cherry.
Neck/scroll was made from two pieces of cherry joined with a seam down the middle. Fingerboard was cocobolo. Pegs made on the lathe from cherry. neck/fingerboard came out a little too narrow. I used a ground- followed by a couple of coats of dark maroon shellack- then oil varnish.. Had an arching that was apparently larger than standard--- a normal case wouldn't quite close with it inside. But it sounded quite nice---- plenty loud - but an
interesting and engaging sound. a professional player who has been playing
for 65+ years liked the sound and feel better than #2 even though it was
kind of homely and non-standard. ( I think I did the tea/modes on # 1 also)

Have I just answered my own question without immediately realizing it ?
Use the general grad pattern I used in #1 for the plates in #3 ??????????


PS-
I think I remember someone suggesting that shellac could be too hard of a finish and might lead to a harsh tone...... Can anyone comment on that ?
I really like the colors I can get with it . I was able to get some fantastic
optical effects by using a wet on wet technique with different colors. Seemed like it wanted to be an interesting ground. Did a tea stain - then a glue ground- then tinted shellack. Tried rubbing it with
0000 steel wool when dry - then doing a burnishing with a rough rag....
you could see yourself in it ---- and if it was too opaque in spots it was easy
to work it down locally to equalize the saturation of the coloring...
I think I remember I adjusted the coloring of the shellac with liquid organic dyes. (dark red, red-brown and burgundy and also yellow.)

Tim
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Michael Darnton
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PostPosted: Thu Oct 06, 2016 7:50 am    Post subject: Reply with quote

Shellac is fine. I use a lot of it. It isn't really hard--more like stiff leather--and I think that what it does to tone is positive.

I have noticed over the years that among professional players amateur-made violins seem to have a discouragingly high hit rate of tonal acceptance vs their construction quality--higher in one is often lower in the other. It's often the same with new modern violins by pro makers--take away the sales snake oil, and often the violins without pedigrees can be better.

There's a lot to think about there. My personal thought on it is that too much intent results in an instrument that runs in tonal tracks--does only one thing. I think tuning does exactly this. If that's a good "thing" that it does, then advancing or beginning-pro players can be impressed, momentarily, until they discover all of the tonal things which aren't available to them because variation has been intentionally designed out to make a violin that can't be played to sound bad. This seems like a good thing if you're beginning, but it's like learning to drive a car properly by driving a train on tracks. Some players, if they don't spend a lot of time with a great instrument, never catch on. Some of them will eventually figure out that spending tens of thousands of dollars to get the equivalent of a one-stop (voice) pipe organ may have been a bad idea. Some never catch on.
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nichols.az@gmail.com
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PostPosted: Thu Oct 06, 2016 1:24 pm    Post subject: Reply with quote

I was watching a discussion given by Sam Zygmuntowicz and his solution for taming a somewhat loud or garish violin was to modify the bridge somewhat by either having it thicker or shaved thinner, thus muting or unmuting the sound.
Perhaps you could try a different bridge.

My .00002 cents worth.
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rs
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PostPosted: Thu Oct 06, 2016 3:31 pm    Post subject: Reply with quote

Michael Darnton, as always you make me think and I really appreciate it. You have helped me more than you will ever know over the years.
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Michael Darnton
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PostPosted: Thu Oct 06, 2016 6:47 pm    Post subject: Reply with quote

I think this is the problem with searching for a "Stradivari" or "Cremonese" sound---really, these instruments are treasured specifically because they don't do just one thing. They can be whatever the player wants them to be. I believe most of the "science" directed at the violin problem encourages thinking in terms of the "best" sound, rather than the most flexible one, and my interactions with science-type makers has confirmed that, for the most part; though they often will deny that this is what they're doing, their approach and results say otherwise.

Today I was reading, thinking about this problem, about a player who uses and compared for an article both a modern violin and a Strad. He stated that the modern was raring to go, loud and full, where the Strad was "harder" to play because it didn't give up everything easily. I think his taste reflects the laziness of youth. :-) There certainly is a tendency of young players, who are the main purchasers of new violins, to think in terms of how easily the violin plays, and how good it sounds. You don't usually hear this line from the players of the best old violins, and notice that the most respected, by Guarneri del Gesu, are often cited as being difficult to play.

They're difficult because they ask the player to make decisions, and to draw out what he wants. A friend of mine put it this way about his purchase of a Strad: (paraphrased) "For six months I played it and thought there was nothing too special about these violins. Playing a piece was like walking down a hall from one end to the other. Then one day I did something a little different, by accident, and noticed a tonal door on the hall that I'd never seen. Soon I was experimenting, and finding the hall lined with doors, each giving me something different. No violin I had played before had any of those options."

That's the difference. If all you want to do is get from the first measure to the last, with the least possible pain, pick a simple violin that just plays itself, and sounds good, easily. This is particularly appealing to young students. If you need to make music, pick something more versatile. When a mature player picks a violin of the simple type, I think we all lose. I've had this discussion with professional musicians about various violinists, and you'd be surprised how often the same names come up. They may not realize there's a problem, but their colleagues certainly do. :-)

One of my students asked how to make a violin that would win competitions. When we drilled down on the question, he decided it meant a violin that anyone could play immediately, and that would sound good for five minutes. One of my personal tests is to put on a CD and my best headphones, and see how long I can bear to listen before the shop-vac-like whining monotony sets in. I guarantee to you that once you get a feel for that sensation you will become a very selective listener and start to realize what a great violin is not . . . or is.

The opposite of that is, for instance, Zino Francescatti. I asked a friend of mine how he "does that", and the friend, an excellent musician, said "Man, if I knew, I'd be doing it!"
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jethro
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PostPosted: Fri Oct 07, 2016 2:06 am    Post subject: Yes----- Reply with quote

Michael---- yes -- I sort of felt what you are describing just from my
intuition about how the physics of how the violin works.......
There is only so much energy supplied from the bow to be turned into sound. Seems like you can have a plate that puts a large percentage
of the total energy into a single or a few modes/frequencies and yield a huge volume (bright) ----- or you maybe could have a plate which
refused to dump all it energy into just one place in the spectrum-- and have
other frequencys which which could be fed energy along with others.

I definitely think the latter is better than the former.... (as you relate)
the question -- as a maker trying to achieve that situation -- I don't have an
intuitive idea how to steer it (during the build) away from the former and
more to the latter.

I keep thinking of radio circuits..... A "high Q" oscillator which runs with
huge amplitude and rings for a long time--- but has a very narrow output
bandwidth. Vs. a "medium Q" circuit which operates with much less
amplitude, has a wide distribution of possible frequencies- and has some inherent damping. (the Q factor is a measure of how much energy is dissipated as the circuit as it runs )

Violin #2 sounds better (in some ways) when I put a rubber mute lightly
over the top of the bridge. Have you ever tried alternate bridge woods
which might be slightly damping ? (lower Q)

Good to hear that shellac is OK. I love using it. I tried a technique where
I made about 3 or 4 tinted colors--- I brushed on a coat over the ground-
let it dry about 5-15 minutes..... then I came back and added a wet layer of a different color over top the first layer. What I got was a fascinating mingling of the two shades- they kind of melt and partially blend but still
leave interesting transition areas which seem to exhibit the multiple reflection effect ( which I cant remember the name for that effect). I havnt
done it on a instrument-- just on plate scraps. I havnt figured out how to
control the effect sufficiently to be able to trust doing it on an instrument.
it looks like if you let it mingle to deeply(too wet or too soon) - the colors just average and the effect disappears.
Perhaps I can post a pic of the neat optical effect.

I bet artists who paint paintings might be able to shed light on how to
"play" with the technique. Maybe water colors..... I will ask my cousin-
as he is a professional painter- and a really good one too.

Tim
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