Violin Forum/Message Board

[John Cadd]

One problem I had with a guitar was several notes would not resonate . By labelling each Dud note beneath the strings and writing the note name it showed that these notes were all the same or their octaves . I noticed that tapping the top and back produced the same note. Nothing very complicated about that . So as a random experiment I added some weight at the bridge to see if that improved the dud notes .Bluetack was used and it was simple to add or subtract weight . That was definitely working and refining the exact weight showed it was a valid improvement . The dud notes had all become resonant. More than that the notes above and below the dud notes had all become more resonant and "complex". I changed the weight of bluetack for a short length of stainless steel square rod and glued that to the bridge beneath the strings.
So could a similar test be made for a violin? Good question .
Make a violin with the plates tuned to exactly the same note. Use the lower strings without fitting a soundpost for now. Pluck the strings to look for dud notes . There are no frets as restrictions but the principle is the same.If any dud notes appear ---try adding weight close to the bridge. See what happens . The soundpost added later might make the experiment fail but it`s hard to know in advance . It might lead to a tunable violin with controllable tone. Just a thought .

[John Cadd]

This accidental discovery about guitar dud notes was something I wanted to transfer across to violins. MrDarnton suggested using magnets which is a quick way to experiment . But like many ideas it went dormant. I was doubtful about where the extra weight should be.What re-awoke the experiment was the strange research about lasers and violins . I still don`t understand it but I read about In Plane and Out of Plane vibrations . Well ,enough to think I understood something . My thought was that a weight fitted in the middle of the bridge would be affecting In Plane vibrations. So combining magnets and bluetack I might be able to pin down one exact weight rather than trust the magnets on their own . The bridge does not move any part out of it`s own plane. Not too hard.and worth a try .
The guitar bridge "rolls "to and fro . The violin bridge "rotates" around it`s centre. So add weight as close to the cehtre as possible but allow the bridge details to continue working .A heavy bow action does not stop a violin working so don`t panic .

[Michael Darnton]

Yes, totally ironing out the sound of a violin by muting it is one easy way to iron out inconsistencies, but it doesn't make what most players would consider to be a "good" sound.

One of the things that makes a violin sound like a violin rather than an electronic synthesizer is that every note on a good violin has a different sound, and this is a good thing. The trick is to keep all the inconsistencies at around the same degree.

I'm suspecting that you were dealing with the primary wolf note, which is usually around C or C#. Though you hear the whole instrument vibrating at that note, the source is actually two areas of the top, one about 35mm directly below the bass f-hole next to the bar and a similar spot about the same distance above the f. You can hang a weight there and kill those notes without killing the whole instrument.

You can find the exact area by having someone play the offending note and running your fingers around the top to find the spot that's going wild with vibration and put the weight there.

Once you've found the spot how close to it you weight directly affects the amount of effect your weight has. One strategy is to clip two small magnets together, one inside, one outside, and move them around that spot to find the effect you want. Then you can leave them or glue an equivalent weight inside at that spot.

Another method is to mess with post tightness and position. Usually tight and closer to the bridge foot works enough to handle the problem.
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[John Cadd]

The guitar change made a definite improvement and could be compared --before and after by simply taking off the weight on the bridge . No muting at all . You should advertise for a guitar like this with dud notes and see how it sounds . That`s the guitar situation .I thought --How many times in a lifetime would an improvement be so easy ?
Remember most guitarists have no idea what`s happening inside . Your reaction is identical to guitar forum "leaders" who dismiss the change without trying it . Something stops them . No matter how simple it is .
With violins (many of which are far from perfect ) the players will also not know what is happening inside.
The magnets for violins idea is very useful to protect varnish .I just tried to work out where would be the best position .Also a good chance to ask what on earth the laser experiments taught us. Playing Italian violins like a zylophone with elastic bands .

[John Cadd]

The trick with adjusting weights of bluetack is pretty basic . The alternative using magnets is also very interesting but really quite dangerous . Temu are selling Neodymium rare earth circular magnets in incredibly small sizes now 150pcs all 3mm x1mm size at £1.54 .
But managing them would be a fearful business .If you accidentally let one bang against a stack of magnets it would probably splinter and could get in your eye. Around delicate spruce and varnish and also inserting inside a violin is asking for serious trouble .
So a topical subject with some black comedy mixed in . On a guitar forum the danger of sticky bluetack was the only worry . Sadly these magnets are advertised for fridge decorations .Children would be in grave danger around such tiny magnets.
But the basic parrallel between two string instruments still remains . I will cheerfully admit my first test on dud notes had no technical knowledge involved . Strad would have been proud of me . Practical audible results . A useful little mystery to unravel and no lasers or elastic .

[John Cadd]

Apart from Wolf Notes on a violin the fact that a bow drives the strings separates them from guitars . So in a way dud notes will not show up on a violin. Plucking a violin is damped by the sound post. But removing the sound post and testing for dud` might reveal what is already hiding there .There is still alot of guesswork about these effects .Edgar Russ seems to list the different ways to kill wolf notes but it does not sound very certain .A hidden dud note (because of bowing and the sound post) might still have a negative effect on tone .Not for every violin but some violins .And there must be plenty of them .

[John Cadd]

What I changed on a guitar was pretty drastic .The added weight at the bridge was a stainless steel rod about 3 inches long and 1/4inch square . That was a 3/4 size guitar made by Roca in Valencia. A full size Roca needed a much shorter rod to make the same change. But this is the point where people stop believing the change had no negative effect .There was no damping . If you believe it`s better not to think about plate tuning at all then you will disregard anything vaguelly connected with plates interfering with each other . But the 3/4 size guitar had the basic tap tone front and back at exactly the same note. Did the maker realise that? Guitar makers struggle to predict what notes they will end up with . But there could be some benefit in aiming at something that can work very well if you get lucky .Getting close can also be dangerous . Edgar Russ says wolf notes on a violin also indicates the violin is very good . That`s part of the mystery .

[John Cadd]

I might have a chance to test this theory as the broken violin I am assembling has both plates with the same tap tone. They were different separated but glued on the ribs they are as close as you could get . (accidentally ) .It`s just a basic tap on the bridge area and on the same place at the back .The neck is not connected yet. The Edgar Russ video about wolf notes ends with adding a hollow metal tube attached to a wooden disc for gluing inside the soundhole edge. The hollow tube has something like playdo inside it . That feels familiar. The weight was tested externally first . The playdo material gave a chance to find the ideal weight . That is a different approach that depends on Damping . Alright if it works.But it is a different way to solve the problem. And it may be a different way to solve a different problem rather than the same problem .We may be working on two unknown unknowns. (Room for some light relief.)
My angle is more to alter the plate resonance slightly which is different to straight damping but it may fail completely .The "skating close to the edge " feeling is what makes it interesting . The least weight to get the best effect is the aim .But where and how much . The Russ video demonstrated on a cello .That gives less freedom in a way .Too much room to choose.

[catbrain]

John---

I have postulated that the bridge--- acts as an intermediary between the strings ( the driving force ) and the top/body (the resonator)

I have thought that one might think of the bridge as working like an electronic filter network. Nothing gets to the top except what makes it THROUGH the bridge. So the resonances of the bridge could have a large effect on the final sound.

Maybe we need a way to test bridges as we trim them..... the way some people do tap tones for plates. would think that bridges resonances would all be on the high end ????? but there could be many modes for a bridge.....

[catbrain]

might be pretty easy to make a simple machine to test bridges.
rig up a driver that outputs a calibrated constant amplitude driving signal.
drive the top with that and then graph the amplitude that results at the feet.
Then you could see the filtering..... How about that ?
Prob a way to normalize the input signal on some kind of audio software.....