ctanzio

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About ctanzio

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  1. ctanzio

    Old strings

    Damping and elastic modulus of a synthetic material is unaffected by creep. Simple, permanent stretching should have little effect on tone after the string is retuned, EXCEPT.... Violin strings are not a thick, single strands of nylon. They tend to be multi-filament and are wound with multiple layers of wire. Considerable research has been done into the behavior of multi-filament synthetics because of the application to many industries outside the music world. Creep and vibration, even under "modest" loads, will tend to delaminate the filaments and increase the internal friction (damping) of the string. Similar affects occur with the wire windings. Dirt and rosin buildup, and finger oils and salts penetrate into the windings and filaments and over time contribute to friction loss (damping). The "ideal" string in terms of longevity might be a solid synthetic with very low creep rate, but with enough density not to need metal windings to keep the string at a usable diameter.
  2. Follow the advice of the former concert master of the London and New York Philharmonic Orchestras, Rodney Friend: when practicing or performing a piece, never stop playing. During practice, you can correct it later by playing the troublesome section slowly, then up to tempo. During a performance, most people won't notice. And if a good part of the audience is friends or family, they will still think you a musical genius for playing an impossible-to-play instrument.
  3. Wonderful videos. Thanks for posting. I watched a lot of instructional videos on phrasing, but the challenge for an amateur is to extract something usable. Greenhouse is discussing phrasing concepts with technical masters of their instruments. Most of these phrasing videos have advanced players as their subjects. How does one begin to understand and implement phrasing? For me, it started with Heifetz and Zukerman master class videos where they were hollering, "More Bow!" at their students. Greenhouse says essentially the same thing at the start of the first video. It opened up a bunch of techniques to tie notes together or set them apart as a recognizable phrases.
  4. Some words on gluing open seams. You an buy usable wax warmers for about $20US to heat up the wood glue. Get one where the pot can be easily removed and has a lid if you can. A simple heat knob with temperature settings makes it easier to use. I tend to set mine between 140F to 150F. Cooler and the glue sets up too fast. Hotter and you approach temperatures where oil and spirit varnishes can break down. You can buy ground, dry hide glue online from various suppliers of violin and guitar tools, like StewMac. For a hobbyist, a $30US cannister might be a lifetime supply. >grin< You might be able to find less expensive and smaller lots. Avoid liquid hide glue. Although very convenient to use, these glues do not hold well in shear/tension loads which are common at the plate/rib joints. Joints that are entirely in compression, like the nut/neck surface, will hold OK with the liquid hide glue. Add a tablespoon or two of ground hide glue to the pot and add enough cool water to just cover the glue. Let it sit until the the water is absorbed and then heat to 145F. The glue should eventually achieve the consistency of a thick liquid. For open seam repair, I like to add a little water at a time until the glue flows almost as free as water. The idea is to reconstitute the fractured glue that is already in the joints by applying a very thin layer of hot glue. Buy a thin 1" wide spackling knife to apply the glue to the open seam. Dip the knife into the glue to get about 1/2" of the tip wet. Leave it in a bit so it reaches the temperature of the glue. Then push the knife into the open seam, gently move it back and forth to spread the glue in the joint, then while gently pressing on the plate, slide the knife out. Repeat until you have put glue along the entire length of the open seam. You want to avoid "forcing" the knife into either side of the open seam where the old glue is still holding the seam together. Dried hide glue will fracture with a focused load trying to pull the seam apart, which is one of the reasons it used in violins where the plate might have to be removed to do repairs. You can find lots of ideas online on how to make clamps for violin plate repair. You can also just use some inexpensive, thin elastic cord and wrap it around the violin body. Place a small block of wood on the plates on either side of the open seem to get the cord to add more downward pressure on the joint. Practice this before gluing so you can do it rapidly. You do not need a lot of pressure on the plate. Just enough to visibly close the seam. Have a bowl of hot, clean water and a rag available to wipe off the excess glue that will spread out of the joint. The rag just has to be damp, not dripping wet. Do this as soon as possible after gluing. Typically, the glue will not damage the varnish before it hardens, but if you allow it to harden on the surface it becomes difficult and time consuming to remove. Jacob had posted a formula for a cleaner that works well for removing years of dirt and rosin build up. If I can find the post I will repost it here. Otherwise, a rag that is slightly dampened with warm water that has had a tiny bit of liquid detergent added to it will work wonders. There is a simple method for polishing up wood surfaces with a very thin mixture of amber or clear shellac and denatured alcohol that you might want to consider. But that is a topic for another thread. Also, some method to add a little color to exposed, white wood surface can add to the appeal (if not the tone >grin<) of the violin. I like to add a drop of yellow food coloring to a little water, then dab it the exposed area. A little amber shellac or colored oil varnish completes the touch up for a cheap violin. Almost looks like the worn out varnish areas on a Stradivarius! If the violin has any real monetary or historic value, best to leave the touch up to an experienced professional.
  5. This is one of those areas where a finite element stress model could add some insight. If the glued area just off the chamfer was primarily in a state of compressive stress, then glue failure would not be an issue. One can imagine what the stress condition might be by thinking about how the body and plate deforms as the strings are tensioned, but my experience is that intuition is frequently contradicted when the details of the loading conditions are carefully considered. In this case, intuition would say that the downward force at the bridge would tend to put the block joints in compression against the top. But there might be a rotation of the neck upwards due to the tug of the strings that might offset part of that compression and make the area near the chamfer go into tension: greatly increasing the chance of glue failure. My intuition is that any bending moment at the blocks is due mostly to the deformation of the plate due to the load at the bridge. That would tend to make the chamfer edges experience a compressive stress while the rib edges might go into tension, or at least a smaller compressive stress.
  6. Small changes in hair length can have a noticeable effect on the playing characteristics. Sometimes the workaround is to adjust the tension from what you were using before the repair. For example, I had a bow that had considerable distance between the nut and the leather when it was at a tension I found acceptable. After a rehair, that distance was considerably shortened and made the hairs feel stiffer, especially for bouncing type strokes. I lessened the tension a bit and the feel returned to the bow. Since I place my thumb completely on the leather, the distance between the nut and leather is meaningless to me. But for players who learned to play with their thumb over the edge of the leather, it might be a big deal. From a physics perspective, it is unlikely that a change in plug shape would affect the bow playing characteristics, unless there was a significant change in the mass of the plug, like from balsa wood to a lead sinker.
  7. This is a fundamental truth of driven systems that is difficult for many people to comprehend. To try and state it more clearly: when you play a note on the violin, the standing waves that develop in the body have the same frequencies of the vibrating string, not the natural frequencies of the violin body.
  8. The tension in the string and the angles the string makes going over the bridge (nut to bridge, bridge to tail piece) define the string force on the bridge. For a set bridge height, baroque vs. modern tail piece will not affect the string angle of the string going from nut to bridge. So Hargrave must be inferring that a baroque tail piece floats higher above the top plate than a modern tail piece. This will lessen the angle of the string going from bridge to tail piece and thus somewhat lower the net force of the string pushing on the bridge. I do not know if baroque tail pieces actually do float higher than modern. I will defer to the wisdom of those of have setup baroque tail pieces.
  9. Not to start a discussion on this, although I don't consider the topic "political", are you referring to the Blind Audtions editorial?
  10. Resin and oil will form a solution from the start, which means the resin molecules are evenly dispersed throughout the oil but not "attached" to the oil molecules. As the solution cools/hardens, the resin comes out of the solution. The purpose of heating the solution for an extended period of time is to provide enough energy for the resin and oil molecules to bond with each other. How long and what temperature is a complicated question and requires a technical understanding of the reaction that is not really needed for practical application. But in general, the 250F/2hr rule is good enough for the range of resin to oil mixtures one is likely to find useful for a varnish. Heating it for a longer period of time results in the oil/varnish mixture forming more complex chains of molecules, higher viscosity and shorter drying time. At some point, the structure of the molecules begins to dramatically alter and the varnish becomes darker and the color more intense. A 250F/2hr varnish will have very little color beyond what the resin and oil initially had, but heating it at that temperature for an extended period of time usually yields a varnish that will color nicely. There is some debate as to whether one should use higher temperatures to get a darker varnish, but I think one runs into the danger of causing the resin/oil to decompose and become darker because of an increase of opaque elements due to the decomposition. This is a bit off-topic from the original question. I think cooked oil varnish is best left to professionals who have the know-how and facilities to make it safely.
  11. There seems to be no practical way to make a colophony/oil varnish without heating. The challenge is that colophony and linseed oil will not fully incorporate with each other without being heated together at about 120C (250F) for two hours. The temperature and heating times can be varied a bit depending on the proportion of colophony to oil, but 120C/2hr should be good for up to 2 pats colophony, 1 part oil by weight. Colophony will readily dissolve in alcohol, but you may encounter problems with its dried finish if you do not melt it first to drive off volatile compounds. So you are back to the problem of heating a smelly chemical. You might be able to buy pre-melted colophony which would avoid that problem. I've experimented with colophony/shellac mixtures to get a harder varnish, but I decided a pure shellac finish had good enough wear properties for a violin or viola.
  12. Lots of phone apps the emulate simple oscilloscopes. Most are free to download. When I want to quickly capture a repeating sound wave form I use Sound Analyzer. It has a freeze button. Vibration of specific parts of the violin, like plate, string, bridge, or the vibration of the bow, would require a transducer attached to that part to capture the dynamic movement rather than the sound. You immediately cross into another realm of cost and complexity. Another option for sound wave shape analysis is to capture the sound and import it into the computer-based, free-app Audacity. Their you can view the wave form in detail and perform a variety of spectrographic analyses.
  13. I spent a lot of time investigating simulated sound fonts and sample libraries of violins and even spent time creating my own simulated fonts and samples. This seems amazingly good and the price is almost too good to be true. Worth checking out if you are commercially involved in making sound tracks.
  14. I wonder if it is a transcription of some of his Concertantes, six of which featured two violins as the soloist instruments. Here are the keys of the six works. See if they match they keys in your book... W.C32 – Concertante for 2 violins & cello in G major W.C33 – Concertante for 2 violins & oboe in E♭ major W.C35 – Concertante for 2 violins in D major W.C36a – Concertante for 2 violins & cello in C major W.C36b – Concertante for 2 violins & cello in C major W.C42 – Concertante for 2 violins & cello in E♭ major
  15. Obvious differences in tone and playability aside, I would say the video demonstrates that Ray Chen is worth $10million for his skill. I was astounded to hear that $69 violin sound as good as it did in his hands.