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About robedney

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    Senior Member
  • Birthday 06/08/1950

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    San Franciso Bay
  • Interests
    I live on a 60' steel trawler (that's a boat) at Point San Pablo Yacht Harbor on the San Francisco Bay. I've been fascinated by violins for decades, although I've never learned to play all that well. I'm working on that part. Aside from the day job, my interest is in developing a reasonably priced, go-anywhere carbon fiber composite violin. You can check on my progress at

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  1. I realize that this is an old thread -- and I haven't been on Maestronet in a long while now -- but we've had an inquiry about carbon fiber sound posts specifically referencing this thread. I thought I'd answer here and share what we've found: We make carbon fiber violins, so you might assume that we'd fit carbon fiber posts. As a general rule, we don't. The reason -- as suggested in some of the replies above -- is entirely pragmatic. Luthiers are well equipped and experienced in fitting/adjusting spruce posts, not so much carbon fiber. As sound post adjustment is a key component in
  2. I can do that (measuring and adjusting the resistance in the area of the bass bar) -- good thought. I've had the same thought (as you, above) about adding damping. My latest prototype is somewhat thicker with more mass. I was looking for a more focused sound, and I thought it worked. The pros I've had play the two I'm working with at the moment like the thinner, lighter instrument better, in fact asking me to make something as thin and light as possible to try on the next round. They felt I was pretty darned close with the lighter instrument. I'm listening to them. So, I'm back to whe
  3. A perfectly fair statement. Part of the inventiveness involved in creating any sort of "upgrade" is taking what you're talking about into consideration. I've learned to monitor myself when it comes to becoming too attached to an idea, and I actually sort of enjoy scrapping something that's not proving out. That takes me one step closer to something that works. Also, I should clarify: I wasn't saying that anyone's views here were wrong. Someone who is very skilled at setting and adjusting wooden posts would appropriately have little interest in such gizmo.
  4. And that's where I think I have something of an advantage. Anyone looking at a CF violin is already demonstrating an open mind. What we've seen here is that many respectable folks have a negative reaction even before any sort of design is finalized. It is not at all a complex gizmo, but the tendency is to decide that it is. In truth it's a rather simple and sensible gizmo. We've also seen that those who have experience successfully installing traditional posts don't see what the big deal is. And, I assume that there is some resistance to making what is traditionally the task of a luth
  5. OK, after pondering overnight and reading the additions above, I'm thinking that step one (working experimentally) is to significantly lower the profile of the existing bar in a prototype. Thanks for the floor joist example John, that helped me with the mass vs. stiffness issue. I have one prototype with a zip off top (it's glued on with black high temp silicone). It also happens to be the variation with the thinnest plates. So, I can record some open strings and spectral analysis before, then again after re-profiling the bar. That ought to demonstrate something. One thing that's occ
  6. I'm quite certain that John's response to you was in good humor.
  7. A _careful_ reading of the gizmo discussed on this thread will reveal that it allows for a great deal of adjustment, very likely with the same results as a wooden post. Part of the design parameters as discussed make it easier to install and adjust -- not just for amateurs but also pros. One thing you can't do with a traditional post is adjust the tension easily. One gizmo version (above) makes that very simple. It's not for everyone, anymore than Peghead tuners or composite tail pieces, but it's far from running in leg irons.
  8. Interesting. Do you remember where? I'm more or less convince that a spring loaded post on its own isn't going to do the trick -- the spring will introduce way too much damping in the linkage. What seems to work is a more or less rigid connection (just how rigid being open to debate). John seemed to suggest the possibility of a spring to hold the thing in place when the string tension is removed, but solid contact when under tension. That might work. And please everyone, don't take offense. We're just throwing ideas around here. Sometimes good stuff comes out of that.
  9. I wouldn't worry about the luthier business -- carbon fiber is unlikely to replace wood in large numbers. Moreover, it I start to sell these things -- instead of just investing in them -- I'll have more expendable income, and the most likely expenditures will be on wooden instruments from contemporary American makers I'd like to own (and Manfio, of course). Edit: I think I need to include the Aussies in that too -- and maybe the Brits. You can see where this is going...
  10. Hah! So right you are (about the speculation). I think maybe you've got a point. The bass bar may prove to be redundant, but I do agree that if you eliminate the sound post you both stray too far from the violin sound (been there, done that) and you remove an important adjustment point. I've found that if you go sans sound post you lose much of the focus of the mids and highs (although you get a richer low end). I'm guessing that this is because the top and bottom plates are no longer mechanically linked, and the bridge behaves very differently without the post in its vicinity. So, I'll
  11. Actually, I'm thinking that it might amplify movement. If the bass bar does indeed rock, beyond some measure of initial resistance it might rock more with more weight on the ends of the beam. This is pure speculation -- and very possibly wrong.
  12. Hey J, only the foot of the post is fixed in position (in one imaginary version, at least). The top of the post can be tapped around to your heart's content. The nice thing is that you could de-tension it just enough to make said tapping easy, than re-tension to whatever degree you wanted.
  13. I hear what you're saying, and I might even agree. In part the question is "simpler for whom?" Such a post would certainly be simpler for the end user -- the player, much in the same way that a modern, well engineered car is simpler to own and more economical to drive than something from the sixties, even though is far more complex to initially make. It's simple for an experienced set-up person to adjust a post, but far from simple for anyone else. I understand any reservations regarding having players messing around with things, but some would be skilled enough to make adjustments and per
  14. And John, I think your idea for a patented adjustable post may have real potential. Despite the way we tend to think here, most of the violins in the world are student level instruments and many of them in schools. Such a patented post could be installed and adjusted in a matter of a few minutes with even minimal practice. Any adjusting tool could be cheap and included with the post. A video on YouTube could demonstrate the process and the results. Many string teachers would be adept enough to do it on their own. Not to put an luthiers out of business, but the schools need all the help t