Lars Silen

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About Lars Silen

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    Esbo, Finland
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    Questions about violin trimming, measurement technique, traditional music, sailing. Looking at science that is being destroyed ... in medicine some 70% of published results can't be reproduced. In climate 'science' it is even worse...

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  1. You should remember that zero is nothing or altarnatively you build a bigger violin like a double bass. Yes: There is one extra zero .
  2. Please notice that my intro was formulates as an "antithesis". It is absolutely obvious that graduation of the top/bottom plates influences the sound. If we go from no graduation to the graduation of a very high end instrument it is obvious that different graduations will produce more or less different timbres in the final instrument. The same can be said about the bass bar, rib thickness etc. The problem is to learn what changes will produce a desired tonal change in the instrument being worked on. I am sure skilled builders that modified strads/guarnieries had a good reason for the changes ... no sane builder/repairer does changes to an instrument only for the sake of making a change. I see This is true when looking at Fry's video. On the other hand using proper tools you can do much more than "scratch ticking". Actually you can do the same kinds of adjustments as the builder does to the final graduation (scraping taking off 1/100 mm of wood at a time) a builder uses to reach his graduation/tap tone/basic ring mode X-mode tuning but it is possible to do those adjustments to a playable instrument. Graduating a fully set up, stringed and tuned instrument is a much more direct and hopefully more objective method than taking the top off doing a re graduation and testing the instrument a few days later. At least to me doing a conventional re graduation by taking the top off sounds as an essentially random process. Yes I second that. I think the fact that there are a number of graduation maps floating around and the fact that a plain copy (for example using a numerical router) of a well known well sounding instrument doesn't necessarily produce an instrument even close to the sound of the original is the proof! My own view is that the instrument works much like the strings. You don't buy strings that have painted markings on them showing how much the string should be stretched to be in tone ... it simply doesn't work. One has to tune the string acoustically to get it in tune. I also think that there is almost an infinitude of working graduations for a good instrument but the graduations aren't random. When you know the behavior of the plates of a violin you can deduce a number of faults by playing the instrument and by listening for known faults that you know how to fix by very slight re graduation of known areas known to influence the sound in a specific way. I think we have roughly the same opinion here too. Very sharp resonances with a high Q-value are not what you want. Every single small detail is a compromise. Some simple examples: - Many violins have a tone that is slightly dry on the G and D strings. When you measure the spectrum to find the reason for the dryness you immediately see that the lowest notes of the instrument are essentially non existent. The "dryness" one hears is the set of harmonics of the tone being played with the base note inserted by the brain. The missing bass can easily be improved by making the channel between the neck block and the upper (neck) end of the bass bar slightly thinner. The effect is very strong and thinning too much creates a bovine kind of old German tone. Adjusting the channel at the other end of the bass bar can to some extent compensate for to heavy changes. Changes of 1/100 mm in thickness are easy to hear but you can't mechanically measure a change that small. - A overly strong resonance may cause wolf notes. It is easy to add a wolf note on the A-string roughly at the tone B (european H) by thinning the area just below the neck block on the bottom plate. Getting a too loud B in this way can be compensated partly by thinning the corresponding bottom area. My view is that we are playing with relations here not absolute resonances. Tapping the bottom on a violin with the too strong B resonance shows that the center of the bottom has a tap tone (whatever it is worth) that is lower than the too thin neck area. My view is that the problem usually requires too much effort to fix without opening the instrument. The solution is to make the center part slightly thinner in relation to the edges. I think you interpret the word "tuning" in a too narrow sense. To me the tuning of the plates is relative adjustments where I look for a specific timbre. An instrument that is properly built according to "good" rules of thumb will produce a strong enough sound when properly set up but the timbre may not be what you sought. An example: I think many violins don't radiate high frequencies properly. The main high frequency radiating areas are close to the f-holes. Measurements seem to indicated that the maximum mechanical vibration when playing on the G-string is found starting perhaps 20 mm up from the bass side f-hole and the area is some 500 mm long and20-30mm wide going NNW. To get a proper timbre on the G-string we want to connect this vibrating area to the f-hole's outer edge (outer edge because the upper part of the f-hole blocks energy partly from reaching the inner edge). Tuning in this case means to make sure there is a proper acoustical impedance match between the main vibrating area and the edge of the f-hole. Adjusting/tuning means that I initially leave the edge thick to allow later adjustment. When I have adjusted the bass channel (see above) to give a proper darkness to the tone I adjust the maximum vibrating area to give balance between the different strings in this case between G and D strings. When the balance is OK I finally add high frequency timbre by properly thinning the edge to couple to the maximum vibrating area. Tuning in this case means I want the same tap tone in the maximum vibrating area and the f-hole edge. Adjusting the f-hole edge must be done very carefully because it is easy to over do it. Thanks for good comments!
  3. Should one understand this in the following way? - All graduations are equal. No need to put any effort to get graduations right because graduations do not influence the sound! - The edges of the f-holes will always radiate high frequency sound in an optimal manner. The thickness of the f-hole edges do not influence the sound of a violin! - If a violin sounds bad the reason for the bad sound is found only in the wood/varnish used! - The form and dimension of the bass bar has been selected only for aesthetic reasons! ------- end of intro ----- I think there are many builders that resort to re graduating an instrument that doesn't work even after lot's of time has been used for proper set up. This would indicate that the first case above is false. Historically it is known that a large number of top quality instruments have been re graduated in former times. My own experience is that it is fairly easy to adjust the f-holes to get a "better" more interesting sound and I think I understand what my adjustments do to the working instrument. The second point thus looks false and the exact thickness and form of the f-hole areas in relation to the top in general is important. Re graduation at least occasionally seems to produce some improvement. I would interpret this to mean that the sound isn't in the wood but in a combination of wood and proper "tuning" of the hole instrument. There are many different tuning methods both while building the instrument and methods to fix problems afterwards. To work any of those methods require time to learn and much experience. I think the point about the bass bar probably doesn't need any comment. My personal view is that Fry tried to use a method that at least for a physicist like me looks sound. If you have an instrument that is a coupled collection of oscillators and you want to improve the sound then you should try to tune important oscillators in order to improve the sound. The problem is of course to know where to scrape/sand and my feeling is that Fry didn't necessarily have the necessary experience meaning that adjustments were partly random. I am sure Fry didn't have a complete picture of how a violin works on a low level which makes it difficult to do rational changes. Fry's tools were also very primitive which means only fairly restricted areas were available for adjustment. A final problem is of course that it is very easy to fool oneself when doing adjustments. We tend to hear what we want to hear and the room where we do adjustments will influence the sound we hear in a major way.
  4. More sound post tools Cutting the sound post to the correct length and the ends to a reasonably correct angle isn't easy. The set of tools below is used for: 1) Measuring the length of the sound post. 2) Measuring the angles of the movable feet. Using templates cut to 2, 5 and 8 deg. 3) Tool to cut the end of the sound post to the measured angle. The holes in the block emplate are bored at 2,5, and 8 deg. Brass inserts are used for all screws. I will modify the feet slightly to make t easier to take out the tool without moving the feet.
  5. Re-sizing s easy. I have another version for Nyckelharpa .
  6. Back after a nice weekend among friends playing traditional Nordic (folk) music at the light house island Sälgrund in Finland. Interesting to read lots of comments with interesting view points. I actually got interested in re-graduating instruments after causing (intentional) external damage to the varnish of a number of instruments noticing that external thinning of the varnish in some places clearly influenced the sound. The obvious conclusion of this is of course that a completed playable white violin can be "post" adjusted from the outside through scraping, sanding or some other method. It is also absolutely clear that it isn't possible to do random changes ... one has to know by experience which changes will improve or eliminate some perceived fault. A good violin is a violin where most of the faults have been eliminated . Of course adjusting a white instrument in this way before varnishing can fix some problems in spite of changes introduced by later varnishing. It is interesting to read (as the devil reads the Bible) that re-graduating an instrument from the inside can't change the instrument in any significant way. If this were true then all builders are doing completely unnecessary work by graduating the inside of the violin before it is assembled. Why not leave the underside flat or only remove material from the inside to eliminate mass. Of course this kind of thinking is pure BS. Cheap violins made for example using numerically controlled machinery generally aren't especially good even if the manufacturer used measurements from a very high level violin as a template. It is absolutely obvious that graduating the instrument changes its behavior I don't think any builder in the world assumes anything else. The big question is what graduation should be used for a specific piece of wood? The reason why it looks like many different kinds of graduations (look at the number of graduation maps found from the net) work and produce usable/good instruments is that tuning specific areas requires the same kind of work process as tuning a string. We don't tune a violin for a potential customer by attaching new strings to the pegs and then checking a table how many tuns the pegs should be turned to produce GDAE tuning ... we all know that this simply doesn't work. If we want to tune the relative strengths in tone of the different strings or the amplitude of specific tone ranges then, as I see it, the only working process is doing small changes and listening to the changes, that is tuning, using the ears. It simply isn't possible to use a fixed graduation map to build top instruments every time ... the proof is, I think, the number of beautifully built violins hanging on the builder's wall because they aren't possible to sell at a reasonable price due to different sound faults ... but where the builder don't want to open the instrument to try another graduation.
  7. I have thought about doing internal varnishing bet I have never really found the need for it. Probably a layer of varnish on either side would change the sound in some way ... ow much? I have no idea. I have also thought about using my own special paint made from tungsten oxide (extremely heavy) to influence the vibrations of too thin areas. My understanding though is that the stiffness of the wood is much more important than the mass of the vibrating are. So ... worth trying but I wouldn't have too high hopes .
  8. Two tools that may be useful to somebody. Sound post tool: This tool is a 3d printed version of the basic sound post position template made from paper or cardboard. The two parts are glued together using Super glue. Let the glue dry for a few hours before use. The top parts has three different scales printed to the tool. The short length wise scale measures the distance from the sound post to the outer edge of the ridge. The second length wise (outer) scale measures the distance from the sound post to the edge of the sound hole. The third scale perpendicular to the two other ones measures the distance from the sound post to the flat edge of the bridge. I think every violinist should measure the position of the sound post in his instrument because it is much easier to restore the instrument to a playing condition after an accident if the old position is even roughly known. The measured position should be stored for example in the violin case. Sound post tool in Swedish is ljudpinneverktyg. For those interested in internal adjustments of a playable and tuned instrument the sanding tool may be useful. The sanding tool procides access to essentially any location in the top or bottom of the violin and also to the ribs. Glue a small 10 mm diameter magnet to the printed base using Super glue. Make a sanding tool to be dropped into the instrument from a similar magnet with abasive sand (for example 80 grit) glued to one face. Orient the sanding face so that it is drawn towards the magnet of the external plastic tool. Let the glue dry for a number of hours before use. The name of the sanding tool is Slipverktyg in Swedish. ljudpinneverktyg.zip fiol_slipverktyg.zip
  9. Builders interested in trying internal re-graduation can try it using the tool below. This is a magnetic sanding tool where one magnet 10 mm diameter and 2 - 2.5 mm thickness is glued to the plastic support using super glue. Let the glue dry/harden for a few hours before use. The working internal magnet is an identical magnet with abrasive sand glued to the side attracted by the outside working magnet. I use 80 grit sand that (found on ebay using the search "sand blasting 80 grit"). Apply super glue on the magnet face and pour a small amount of sand over it and let it dry thoroughly. Suitable magnets can be bought on ebay. Search for "super magnet". For the tool base given you want magnets with 10 mm diameter and thickness 2-3 mm. A thicker magnet gives a stronger pressure and faster sanding. How is the tool used: Use a clean paper on top of the varnish, under the outer working tool, to protect the outer surface and drop the working magnet into the instrument. By placing the outside magnet close to the insert point you will catch the internal magnet immediately. Move the outside magnet to the area to be sanded, it will drag the working magnet to the sanding location. You can feel the pressure on the sanding magnet by trying to lift the outer magnet. To avoid scratching the f-hole when removing the inner working instrument turn the outer magnet on its edge which will also turn the inner magnet n its non abrasive edge for safe removal. The base used for the outer part of the sanding tool is shown in the picture. Unzip the zip file "fiol_slipverktyg.zip" and 3d print the resulting stl file. fiol_slipverktyg.zip
  10. Don, You are absolutely correct (1) in that it is difficult to bow exactly in the same way. The difference plot has a offset estimated from the big major peak at 300 Hz this is simply to make the plot easier to read. Another complication and difference between before/after is also how well the pitches match between the two scales. Playing a half tone scale in tune is not easy . (2) Recordings were done on different days in a "standard" setup. Even fairly small changes in distance between player and microphone may influence the recording level. Small changes in the angle between the major axis of the violin in relation to the microphone may of course also influence especially the high frequencies because because high frequencies are more directed. On the other hand the ear is fairly well fixed in relation to the violin when playing and the ear hears the same difference as the mic. (3) I realized that the Maestronet system showed the pictures in another order than loaded. I corrected the text very fast but you clearly have been reading the old version. You have good eyes and understand what you see ! (For other readers) Absolute level differences between two otherwise identical spectra are of course seen as an offset between two curves that have the same general form. Obviously modifications may both make some resonances stronger and suppress other. The answer to Edi is shown below: I realize that I read the difference incorrectly. There is actually a fairly strong boost also in the area around 600 Hz. What I see as the "zero level" is the area at ca. 300 Hz at roughly -10 dB. The offset used is incorrect but as such not interesting. How much material was removed from the D-area to cause the changes? I estimate that I sanded an area 50x50mm roughly 300 turns back/forth to match the pitch of the knock tone to the pitch of the f-hole side and the wing. A long time ago I measured how fast sanding removes wood. The result then was ca. 0.1 um/one movement back-forth using a set of magnets that is different from what I use today but probably fairly close. The inner working magnet uses 80-grit sand. From this an estimate could be that roughly 3/100 of an millimeter was removed. The area sanded is typically thin so the thickness changed by perhaps 1.5%. The modification is too small to be measured by ordinary thickness measurement instruments but my view is that even a small change like this is absolutely significant when we are talking about mechanical resonances. A warning! Changes are slow when sanding the G, D, A, and E-areas. Without any risk it is possible to sand those areas say 30 - 50 strokes between test playing. No big risk for fast major damage. When adjusting the sides if the f-holes never sand more than ten strokes between test playing. When sanding the wing, for example the inner wing on the bass side (bridge to wing tip), one has to be very careful. Sand a maximum of five strokes and then re-test. It is very easy to sand this area too much. Compare this to the tuning of an accordion reed. Tuning is done by very lightly carefully scraping the reed, sanding or using even a very small grinder is far to rough. The violin f-hole wings are extremely small parts where the resonance changes very much even for extremely small changes. Notice! My experience is that the effect of sanding initially is very strong but it will partly disappear within minutes/hours. This means that a modification in many cases has to be repeated a number of rounds until the modification is fixed. A positive aspect of this is that sanding "too much" isn't a catastrophe because if the instrument is left alone for a few days it may be just right due to the backing of towards the old state. I don't know the exact reason for this effect but I guess that sanding one of the wood surfaces will lower the hardness of the sanded surface. Fairly fast the sanded surface will oxidase and harden which is heard as a partial undoing of the sanding. The reader probably notices that the method is to adjust a tuned and fully playable instrument. Only very small changes are made between test playing. Because the process is fast (sand/play/sand 30 - 60 seconds between steps) the brain still remembers the timbre before a modification which means that it is possible to learn by ear where to fix specific problems.
  11. I have been using internal sanding for a number of years now, essentially the same method as Fry's but using much better tools and probably better understanding. I think people that say that a small amount of sanding/scraping don't have any audible effect simply don't know what they are talking about. Random sanding/scraping/re-graduation won't do anything positive to the instrument but could easily kill the sound. A small example of internal sanding.: I returned to adjusting a violin built a few years ago. Doing some test playing I noticed that the instrument was fairly even ... all strings had roughly the same loudness but the tone was generally dull. Doing some tests I guessed that the f-holes wings were not working properly. It is easy to check this by knocking from a wing to the corresponding maximum vibration area. If the pitch of the knock tone differs then, to me, it means that we don't have a proper acoustic/mechanical match between the areas and this means that the wing doesn't get vibration energy and thus doesn't work properly. When doing comparisons I usually play a half tone scale from the low G up to B on the E-string but with a short pause between each string. This allows me to look at spectra for the strings separately or to do a spectrum for all strings combined. In the present case knocking from the wing towards the maximum vibration area (I call it the D-area) in SW (neck is north) it turned out that the bass side f-hole's knock tone was clearly higher than the corresponding main area in SW. This means that the inner side of the f-hole and the wing are slightly too thin ... which isn't a good starting point because it is difficult to add wood to the f-hole/wing. The solution is to increase the pitch of the D-area and leave the f-hole and wing alone. The question is then: Is the result a homeopathic kind of adjustment or is it clearly audible? I measured a half tone scale before the adjustment and after ... and the main frequency range that was changed was from 2500 - 6000 Hz. The increase in volume in this range was close to 10 dB in some areas which means that the change is very clearly audible. In a sense the wing works as a tweeter. The first picture shows the situation after the adjustment. This is part a half tone scale played in the first position. The program used is Audacity. The second picture is a similar half tone scale played in the same room with the same set up before acoustical adjustment. The third picture is the difference between the two spectra. Notice the strong increase in power for 2500-3500 Hz and a similar boost around 6000 Hz. The sound of the working D-wing is easy to hear when compared to the original sound. Technical data about the recording equipment: Sound card: Zoom R8 @44.1 kHz Microphone: Rode NT1 large membrane mic. The mic was positioned roughly perpendicularly to the violin in the direction out from the e-string side f-hole. /Lars Silen (physicist like Fry but I think Fry didn't know the whole instrument well enough)
  12. I have actually thought that we should try to create some personal communication channels between Sweden and Finland. Of course there are good builders in Sweden too ... discussions between builders is what is needed to learn. /Lasse
  13. Yes it was an interesting competition! Nice violin you had. The sound post is inserted through the so using that as an link to an question (åsnebrygga ) : Do you have any good links to tuning the f-holes and the wings. I think I understand how they work and I am able to tone them in a controlled way. It would be nice to read about other methods (there are surely a number of different processes in use presently). The key to understanding the f-holes was actually that I got access to a high quality Chanot borrowed by my son from one of the rich Finnish organizations. It was the first instrument I have played where I clearly could hear the modulation of the D-string by the bass side f-hole inner wing. Knowing what to listen for helps a lot . Much experimentation together with hints by Molnar solved the mystery. /Lasse
  14. I have made my own sound post tool using 3d printing. If there is an interest in the tool I could upload the stl-file allowing anybody to print their own. A similar tool can easily be made from paper or cardboard but it is nice to use modern technology . There is an description of the tool on my web page https://spegling.blog/2018/09/18/ljudpinneverktyg-for-nyckelharpa/. The article is in Swedish and the tool described is for the Swedish national instrument Nyckelharpa. If there is an interest I can recompile the tool in a size suitable for violin and post a link to the .stl file. The tool can be freely printed and it is ok to print copies for commercial use. The tool in the picture is made for the Swedish Nyckelharpa "guru" Esbjörn Hogmark. /Lars Silen
  15. Lars Silen

    weak d string

    I think the most important options have been mentioned above. I would start with non destructive changes. It is possible to get some feeling for in which direction a sound post change will go by moving the bridge slightly forward/backwards to change the relation to the sound post. Then I would check that the sound post i reasonably well made and that it stands in roughly the correct place. Experimenting with the sound post on a reasonably cheap instrument is a valuable learning experience. I think trying different strings at this stage may also be a good advice that doesn't destroy anything ... Now the destructive alternatives . If you feel the D-string problem is only a small problem and you want to be able to get back to the starting point then it is best to make a new bridge based on the existing one and start adjusting the copy. If moving the sound post doesn't help I would try to very slightly enlarge the opening in the heart under the A-string. Two or three filing turns with a round file should produce an audible difference. If you are using a knife you need to remove extremely little material. My experience is also that making the arch between the bridge feet slightly higher especially in this case on the E-A side could help. It may also help to slightly enlarge the heart over the D-string but less than on the A-side. Everything you do will spill over to the strings close to the change. You can never adjust a single parameter you will often get unintended surprises. You can often fix problems you caused by finding other locations to sand. The key is to do extremely small changes and immediately listen to the result. Other potentially DESTRUCTIVE methods are: - Sand the channel between the bass bar and the neck from the inside but very carefully. This causes the tone to darken but it generally influences the G and the D-string. When sanding here the G and D strings will loose character which will need compensation elsewhere. - Sand the bass side lower bout area roughly defined by mode 2 of the top in http://www.platetuning.org/html/modes_-_tuning_plates.html . - You can also try sanding an area from the other side (E-side) of the X-mode (mode 2 above) towards the tailpiece. This generally gives more character to both the G and the D strings. Don't sand very close to the edge. All changes should be done with the instrument tuned and playable and in very small steps. Based on my own sanding tests it is easy to hear changes where critical areas are thinned a few micro meters (um). With my tools one um corresponds to roughly 10 forward/back movements when using 80 grit sand on the tool. REMEMBER! Doing changes to the bridge or the body may destroy the bridge (can be fixed reasonably easily by making a new one) ... Re-graduating the plates may destroy the instrument if you don't know what you are doing. It is STRONGLY recommended to buy a few cheap Chinese instruments and experiment on them before trying to modify a real instrument. My experience with bridge adjustments is that you tend to destroy a few bridges before you learn to listen and learn when you think you have reached an optimum. Adjusting the bridge isn't a silver bullet that always helps but it is often surprisingly powerful.