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Marty Kasprzyk

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Everything posted by Marty Kasprzyk

  1. The comparisons of musical instruments and the human voice have been going on for thousands of years. See the attached article "Voicelikeness of musical instruments: A literature review of acoustical, psychological and expressiveness perspectives" Voicelikeness.pdf
  2. Yes, strings have improved but a I still feel that 1/10 cello with a 17.75inch (45m) body length doesn't sound or play as satisfying as a similar size viola.
  3. You're welcome to borrow one of my violas if it would help sales.
  4. That's what I suggest too. If you like playing vertical instruments a large viola with an end pin is easy to play. If you're playing for your own enjoyment then I suggest a Carleen Hutchins "Tenor violin" which is between a viola and cello in size and is played one octave below violin tuning. Bob Spear at Singing Woods Violins makes modern versions of them. I think it's a mistake to have really small fractional size instruments played with normal tuning. Their short strings are heavy and hard to bow well.
  5. When something breaks it means either the part isn't strong enough or that the applied load is too large. Early string instruments often had flat top plates and they had low bridges with a shallow curvature. These were suitable for playing multiple strings at one time for chords but as music evolved there was a demand for single note playing. This required higher bridges with more curvature which enabled a single string to be played. Narrower C bout widths helped give more bow clearance. The higher bridges made the string angle over the bridge more acute which increased the downward load on the the top plate. The flat top plates were no longer adequately strong so makers started to use stronger and stiffer arched plates to better resist this string downward load. Thus the sound character of the instrument then followed the increased strength and stiffness requirement. Arching increased the stiffness with little increase in mass so the result was higher resonance frequencies resulting in a brighter but less mellow sound. This was obviously successful and all our violins, violas, cellos and basses now use arched top plates with their sound character. But an alternate path of reducing string loading could have been chosen centuries ago. My instruments use a shallow string angle (~168 degrees instead of about 158 degrees) which decreases the downward string load on the top plate by about a half. I've also adapted the ancient (12th century?) Welsh crwth instrument's design which uses only one bridge foot resting on the top flat plate. The other foot rests on the sound post which goes through a hole in the top plate so this foot's force goes to the back plate rather than the top. This obviously also reduces the string load by a half so the total downward load is only about a quarter of a normal arched plate instrument. The tailpiece is also integrated with the fingerboard so the string tension load is not applied to the instrument body. This eliminates the longitudinal load on the top plate which is a contributing factor in conventional arched plate buckling. The end result is that a flat plate top can survive. Anyway, I'm following the road not taken.
  6. As Don Noon and others have often pointed out-if it doesn't sound exactly like what most players are used to then it is unacceptable. People often don't like change. I've changed everything possible from a typical violin (except for string length, spacing, bridge curvature etc.)different woods and design. It's hardly a surprise that they don't sound typical after a lot of effort trying to do so and this was quite discouraging. However a young player I recently met said: "This is great! I've finally found something different from all the rest." Too bad he's broke.
  7. I watched a good player demonstrate how he could change the sound of his violin by varying his downward jaw force on the chin rest. I think there's several influences: the weight of the chin rest, where it is attached, the amount of force on the chin rest, and the damping effects of the player-left hand, chin, shoulder, and clothing. Women players in shoulder-less gowns always seem to sound good to me.
  8. Years ago I began an experiment to determine the effects of plate arching height on the various resultant vibration mode frequencies and the general shape of the frequency response curve and resultant sounds produced. I was going to start with perfectly flat plates and then make a series of higher and higher arched plates which could be replaced on the same instrument body. For example a top plate arch series could go 0, 4, 8, 12, 16, 20mm heights. The back plates would go in the same sequence. The different arches of the two plates would give 6X6=36 different combinations. If a trend developed I could later go back and try smaller increments if an optimum appeared possible. The simplest and first combination I tried was a flat top with a flat back (0,0). I liked the sound very much and never bothered trying all the other 35 combinations. All of my couple dozen subsequent violins and violas were then made with flat top and back plates. Repeated player and listener blind tests have shown this was a bad mistake.
  9. Another time at a Oberlin acoustics workshop a player after blind testing a del Gesu violin said: "I wonder what recycling bin they found this in." This inspired me to make violins like that.
  10. I don't agree with your point of view that "violin listeners can be easily fooled by louder instrument as well." Fritz found that listeners preferred louder instruments--they're not fooled--they liked loudness. It's also not a short term effect. If I'm trying hard to hear a violin soloist playing a long piece I would prefer they were using a louder instrument or I should purchase tickets to the more expensive closer seats.
  11. A thin rubbery glue joint between the relatively rigid wood parts could act as a "Constrained layer viscoelastic damper" which could add some damping to an assembled instrument. There is probably an optimum damping amount. Too little damping might be undesirable--could be one reason why brass violins haven't caught on. The 3M company makes a light weight damping tape that might help suppress wolf notes caused by excessively high resonance peaks. A nodal analysis could be used to show the location of the offending vibration and a small strip could be applied where most of the bending happens. This would add very little weight to the plate so it wouldn't affect the other resonances much. 3M™ Vibration Damping Tape 434 is a low temperature, silver, dead soft aluminum foil tape. The constraining layer is coated with a pressure sensitive viscoelastic polymer on a blue polyethylene easy release liner. This tape absorbs and dissipates vibration and reduces noise.
  12. Anybody can go out and buy many famous and expensive wines and do blind tasting tests comparing them with not so expensive wines. But you can't easily compare famous old violins with modern ones because of the risks involved--no owner of a famous violin worth millions wants it to compare unfavorably with an inexpensive modern one in a blind test.
  13. The general quality of commercial wine has greatly improved over the last 50 years due to careful control over the wine making process. Unless you make your own wine it is difficult nowadays to find wine that is really bad so wine tasters are having more and more difficulty distinguishing between only good, really good, and great wines. A good wine test is to put out a bunch of wine bottles at a party and see which one is emptied first. I bottle special wines for party hosts. When it's getting late and they want everybody to leave they bring out one of my bottles. A good test for violins is to see how long a good player plays a violin before going on to the next one.
  14. Is this the "clicking" sound at the beginning of a note that good players like to have?
  15. He should have done a metric conversion of the inch measurements.
  16. The area between the f holes could be too thin especially the area between the two upper f hole eyes. This "island area" is known to produce a lot of a violin's high frequency output which may be lacking in your violins. This might be a good place to try Sam Zygmuntowicz's "gluey" stiffening experiments where thin strips of wood are temporarily attached to the outside plate surface with melted rosin. If this helps the top could be taken off and wood strips could be permanently glued on the inside surface. The bridge design also has a big effect on the high frequency output. A heavy bridge might be acting as a mute. I suggest trying a bridge with a wide waist and thin top. For making new violins I suggest you follow Oded Kishhony's method of thinning the plates of the assembled violin with its strings on to monitor how the violin's sound character changes as you thin the plates. This will prevent you from making the plates too thin. Varnishing the instrument will change its sound and with experience you should be able to adjust your thinning to compensate for the varnishing effects.
  17. I made a few violins and violas with the linings on the outside surface of the ribs instead of on the inside in order to strengthen the plate's edge overhang. I got the idea from some old basses like you had mentioned. But they had the same problem that having no overhangs had--shoulder rest clamps didn't work so I gave up making that way. The basic problem is that the shape of a violin or viola is lousy for holding.
  18. I've made several violas and violins with 0.8mm thick 3 layer birch plywood double edging on the top plate and it worked very well at protecting the plate during subsequent disassembly. I permanently glued the plywood onto the top plate with Gorilla glue and then used regular hide glue for the joining the double edged plate to the ribs. The plywood's cross grain direction prevents crack propagation and the plates always came off cleanly without any tear out of the plywood layer. The thin plywood layer is hardly noticeable in the rounded edges. All of my instruments are now made with 0.8mm plywood ribs. I don't see any advantage of using solid flamed maple wood ribs other than they look nice. I have also made top plates with laminated quarter sawn spruce wood. I used two layers of 1.3mm thick Sitka spruce veneer wood boded together with pheno-formaldehyde glue. A vacuum bag & mold were used to form the arched plate shapes. The two veneer layers had their grain directions a few degrees off parallel to a toughening crack branching effect to give better crack propagation resistance than if the two layers had parallel grain. The glue layer also helps reduce crack growth. I believe the main limitation of sound output of traditional violins is the low cross grain strength of solid carved spruce wood. Plates of solid spruce wood can't be made real thin and light because of their tendency to crack. Another potential advantage of the laminated wood approach is the ability to change the material's damping by using different glue materials. The glue layer can act as a restrained layer viscous damper. In my laminations the glue was very hard and stiff with low damping whereas other glues such rubbery contact cement would be soft and pliable with a lot of damping. My currant thinking is that really good players might want short transients of their played notes to give crisp articulations of fast passages. Every time I try to mathematically model this I conclude that the violin's plate should be very light and that it should have a lot of damping. This is contrary to the opinion that tapping of the plates should produce a long ring which would be produced with low damping. But I believe it was Joseph Curtin who observed that a Strad violin top plate was very light and it had a dull thud when tapped. In any case it would have been interesting to see how violins might have evolved differently if Stradivari had vacuum pumps, vinyl bags, different glues, and spruce veneers had been available at the time.
  19. My violins and violas don't have corner points with plate overhangs and they were criticized by players because rubber band type shoulder rests couldn't be attached. Some of these players then used sticky pads instead of rubber bands/sponges. The wide parts of the upper and lower bouts now do have overhangs on the plates so a regular shoulder rest can be clamped on. The top plate's c bouts overhangs are cut completely off which gives a small increase in bowing angle clearance. The bottom end of the lower bout of both plates don't have overhangs and the edges are well rounded to make it less irritating on the player's neck. This also helpfully makes the instruments feel a little shorter.
  20. Hi David, I'm still thinking about reference points for measuring up and down plate arch deformation. If you took a violin from Michigan to places in the Southern Hemisphere like Australia is the top plate now on the bottom with all the deformation directions reversed?
  21. The old string instruments like the cornerless vielle were often held downward like shown in the above posted picture "Angle in Green" . Later instruments had corners and the bottom plate's overhang on the bottom left corner point was used to hold a stretched rubber band so it wouldn't slip off the rib's corner joint. The other end of the stretched rubber band had to be attached somewhere so an end pin was stuck in the bottom end of the violin to hold it. Plate overhang was added to the rest of the perimeter in order to achieve visual symmetry. Sponges were inserted under the stretched rubber band to act as a spacer between the violin and shoulder so that the violin could be held more horizontally in a new style of playing where the violin was held underneath the chin. Another way of taking up space is to use a shoulder rest and the plate overhangs were needed for holding the shoulder rest's clamps.
  22. Doug Cox has a very well organized and systematic record keeping method for all the details of the instruments he makes. I wish I could a copy of one of his sheets.
  23. A speaker cone is an example. It doesn't work without having a flexible edge mounting.
  24. These are big violas and I should have used a wider angle lens to show more of the herd. They were early experiments done to explore the effects of plate surface length and area, f hole area, additional hole ports, and rib heights upon the resulting sound character all while trying to have a large sounding but easily held viola. Many people in the past have mentioned that the ideal length of a viola should be about 21 inches if we assume is sound character should be similar to a violin's. The lowest notes of the two instruments illustrate this. The open G string note of a violin has a frequency of 196Hz and the wave length of this frequency sound is the speed of sound in air of 343m/sec divided by 196 is 1.75 meters. The open C string of a viola is 130Hz so its wave length is 343 divided by 130 or 2.64 meters. The ratio of these two wave lengths 2.64/1.75= 1.5 So the plate length of a viola should be 1.5 times the length of a violin's 14 inch length: 1.5x14= 21 inches long if one assumes the plates of two instruments should be equally effective at directly generating these low notes with their plate surface vibrations. Violas of this length are too difficult to hold. However recent tests have shown that most of the low frequency note sounds indirectly originate from volume changes of the instrument cavity that produces air flow through the f holes rather than directly from the vibrating plate surfaces. The A0, B1-, and B1+ mode resonance frequencies are examples. Much of the differences in sound character of violas is from variations in their A0 frequency and amplitude. I like big violas because they tend to have a low A0 frequency that has a high amplitude which gives them a rich deep sound. The A0 frequency f is mostly dependent upon the square root of the f hole area A divided by the instrument's body cavity volume V: f = (A/V)^1/2 so in order to get a low A0 frequency it is helpful to have a low ratio the f hole area A to the cavity volume V by having a relatively small f hole area. On the other hand in order have a large amplitude A0 resonance it is helpful to have a large f hole area to let air move easily in and out of it. One way of doing both things at the same time is to have a very large viola cavity volume V and just a large F hole area. The viola cavity volume is dependent upon the plate's surface area and the rib height. I found it more appealing to players to increase the viola's volume by having high ribs with a more conventional plate shape and size rather than having the oddly shaped large plates shown in my photograph. The f hole area is then adjusted to give the proper A0 frequency. That's my hole story.
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