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Why not an adjustable sound post with self alignin


Alex_E
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Re Joseph Curtins excellent recorded lecture on "Some Principles Of Violin Setup", at the Twenty-Third Annual Convention on November 9-12, 1995, which relates mainly to the function of the strings/bridge and correct bridge setup.

Under the Dynamic Functions section it relates:

"It is interesting to note that if the bridge were truly rigid it would not matter what it were made of. As long as the weight and dimensions remained the same, the choice of bridge blank and the shape of the cutouts would make no difference to the sound.

This, by the way I believe is very largely true for the violin sound post. Research has shown that the sound post had no resonances falling within the important areas of the violin's range. This means that the post is acting as a rigid column and neither flexing nor compressing/expanding longitudinally. This implies it does not matter whether the post is made from old wood or new wood, "good" wood or "bad" wood", providing of course, that length, fit and mass are optimal. Rene Morel, speaking from long experience, stated as much in a lecture he gave at the 1994 Guarneri exhibit at the Metropolitan Museum in New York. I myself have have found it to be true, though on the basis of far less experience."

Assuming he is correct and the function of the post is simply to transmit the vibrations of the bridge to the bottom plate, then theoretically, it may be possible to design and make a suitable sound post both adjustable for length and with self aligning feet, for both easy initial fitting AND side to side movement with it's built in length adjustment. In other words a Universal Sound Post that can be adjusted for an exact fit into all violins.

Any comments?

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Many years ago I recall fitting a few of those "perfect-post" sound posts which were similar to what you describe. The post itself was made of spruce and could be adjusted to any length by removing wood from the center portion where it came apart in two pieces. It was aligned with male and female halves. Once the initial length was obtained by cutting off what was needed from the female half, you simply put it back together and inserted it into the instrument. At each end of the post was a flat circular nylon foot on a ball joint that was fit into a socket at each end which allowed the feet to automatically adjust themselves to the angle of both plates when pulled into position. I can't remember the name of the man who invented it (and patented it), but I recall fitting several of these in the early 90s. Although the idea was a good one, I found that the violins tended to be a little sluggish with this post compared to a well fit one piece all spruce post ...

... of course once the post was cut it could not be made any longer, just shorter by removing more wood from the center, so it is a bit different than what you are considering. Another major draw back was the price, if I recall correctly they were about $50.00 each directly from the inventor.

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That's interesting to know that the theory has already been put into practice, I did a search on Maestronet and Google earlier but nothing showed up.

Like all inventions there are several ways they could be made, I guess the most important factor would be the need to maintain the same, or similar, material structure and not introduce any material that could have a dampening effect, the nylon foot may have contributed to the sluggish effect.

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A few months ago, I was setting up a violin, but had run out of new sound post wood, and every old sound post I had on hand was too short to reuse in that instrument. I was still curious to see how it would play, so while waiting for some new materials to arrive, I decided to experiment a little with some sound post doctoring.

I lengthened a short post by gluing a little disc of spruce to each end. I cut the spruce used for these discs lengthwise with the grain so it would be easier to work with and so it would be less rigid than the grain of the sound post, running perpendicular between the plates. The logic here was that less rigid ends on a sound post might be slightly less abrasive against the inner surfaces of the plates and might conform just a little to their contours, helping improve a less than perfect fit (there’s your self-adjusting element). Counter to those possible advantages was the question of how these little pads would dampen vibrations between the plates. By the time the post was fit, the discs at the ends were each about 1mm thick.

The violin sounded so nice with that post, I considered leaving it there, even after the new sound post wood was available, but that wouldn’t have been a complete experiment, so I cut a new one. Installing a normal post confirmed that the little extensions on the short post did have a dampening affect. The new sound post made a measurable improvement in the depth and brilliance of the violin.

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It seems one would risk losing vibrational information in the soundpost in any area of transition between one material and another, i.e. from wood to nylon, from wood to glue to wood with grain in a different direction, etc.

The bridge and soundpost are amongst the most sensitive parts of the acoustical system, are they not? And, therefore, they would be most susceptible to minor alterations in material and fit.

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"Research has shown that the sound post had no resonances falling within the important areas of the violin's range. This means that the post is acting as a rigid column and neither flexing nor compressing/expanding longitudinally. This implies it does not matter whether the post is made from old wood or new wood, "good" wood or "bad" wood", providing of course, that length, fit and mass are optimal."

The sound post doesn't need to resonate, but it would need to be of sufficient rigidity at an appropriate diameter to accurately transmit the vibrations of the violin top to the violin back without damping those vibrations (and without breaking through the instrument. Length, fit, and mass are therefore not the only characteristics that go into a suitable soundpost.

Since a metal instrument might deform over time, but not crack, you might have other options than wood for soundpost materials.

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"It seems one would risk losing vibrational information in the soundpost in any area of transition between one material and another, i.e. from wood to nylon, from wood to glue to wood with grain in a different direction, etc."

You're right about that. I really figured it myself even before trying my little experiment, but went for the empirical evidence just to be sure.

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"Rigid soundpost" implies that the two endpoints are essentially the same point in the structure, if you ignore the mass of the post. In fact, models of the violin used for analyses sometimes consider a small area in the top (near the post) to be an extension of the back.

But one thing always bothers me, and I think it is bad science. "The post transfers vibrations from the top to the back." This is the offending statement and is not very meaningful to me. In fact, I think that it comes from a misunderstanding of the physics of the violin. I think I can justifiably say this because the word "vibrations" presumes to be a reference to the dynamics of the violin.

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And then there is the problem of taking a simple workable solution (like the sound post) and attempting to "improve" upon it with ever more complex and increasingly unworkable alternatives.

The sound post has already been reduced to its most workable and simplest form. There is a certain amount of skill required in order to be able to fit and place one correctly - but the effort is well rewarded in the fact that it is eminently workable; it serves its function perfectly. If you can do that well, THEN go ahead look for an alternate method. The chances are that you won't be interested in a substitute then, though.

I really hate to be a killjoy, but there is absolutely no reason to “improve” the sound post by making an adjustable one, unless you have no skill in fitting one in the first place. Most probably it won’t be as efficient or work as well as a traditional one regardless of the solution.

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Where might we be today if Stradivari had had aluminum availbable to him? Or if he had merely accepted Amati's designs as being the ultimate? There's always room for innovation & improvement, Alex. Maybe your idea could result in a "try-post"- inserted & moved around at will while test playing the instrument, & THEN, after determining the optimum placement & length, replace it with a hand-set a spruce soundpost.???

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"Maybe your idea could result in a "try-post"- inserted & moved around at will while test playing the instrument, & THEN, after determining the optimum placement & length, replace it with a hand-set a spruce soundpost.???"

Even better would be a "try-post" with a built in meter able to actually give variable readings that would allow the required "sweet spot" to be precisely determined, before fitting a traditional post in that exact spot.

A scale of readings could be recorded for future use by test placements, to show the recording needed for specific placements needed to enhance or lessen the brilliance of a single string, broaden tonal range, etc, etc, then to rectify a tonal defect in an instrument the "try-post" could be moved around until the specific reading was obtained, to enable a a single precise placement of a Spruce sound post to give the enhancement required.

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"Even better would be a "try-post" with a built in meter able to actually give variable readings that would allow the required "sweet spot" to be precisely determined, before fitting a traditional post in that exact spot.

A scale of readings could be recorded for future use by test placements, to show the recording needed for specific placements needed to enhance or lessen the brilliance of a single string, broaden tonal range, etc, etc, then to rectify a tonal defect in an instrument the "try-post" could be moved around until the specific reading was obtained, to enable a a single precise placement of a Spruce sound post to give the enhancement required."

I'm going to say something neither of you is going to like, but please listen.

Alex, you cannot improve something you don't understand to begin with. It is logically, practically, impossible.

If you cannot recognize the sweet spot yourself, THERE IS NO METER THAT WILL RECOGNIZE IT FOR YOU. How would you know the meter was right to begin with, unless you were able to find and recognize it? And if you were able to do that why use the meter? Plus the fact that there is no “sweet spot” without a proper fitting sound post to begin with.

99.9% of these type of ideas come from people who either have never made a violin, or are on the first couple. Then, they start understanding that it is going to be years before they understand the traditional methods well enough to offer up "improvements".

I'll stick with my original position. Learn the traditional methods first. THEN, improve on them if you think you can. By then you will probably see enough to realize why what you thought would work before would have been a waste of time.

But, If you never learn them to begin with, you will not be able to improve them.

Of course you don't have to believe me... good luck with this idea.

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"Where might we be today if Stradivari had had aluminum availbable to him? Or if he had merely accepted Amati's designs as being the ultimate? There's always room for innovation & improvement, Alex. Maybe your idea could result in a "try-post"- inserted & moved around at will while test playing the instrument, & THEN, after determining the optimum placement & length, replace it with a hand-set a spruce soundpost.???"

Good sentiment but faulty logic, Ron1. We must assume that Strad apprenticed somewhere, learned the craft, mastered it - then effected his changes to arrive at his own model. Not the other way around.

It just doesn't work that way.

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[quote

I'm going to say something neither of you is going to like, but please listen.

Alex, you cannot improve something you don't understand to begin with. It is logically, practically, impossible.

If you cannot recognize the sweet spot yourself, THERE IS NO METER THAT WILL RECOGNIZE IT FOR YOU. How would you know the meter was right to begin with, unless you were able to find and recognize it? And if you were able to do that why use the meter? Plus the fact that there is no “sweet spot” without a proper fitting sound post to begin with.

99.9% of these type of ideas come from people who either have never made a violin, or are on the first couple. Then, they start understanding that it is going to be years before they understand the traditional methods well enough to offer up "improvements".

I'll stick with my original position. Learn the traditional methods first. THEN, improve on them if you think you can. By then you will probably see enough to realize why what you thought would work before would have been a waste of time.

But, If you never learn them to begin with, you will not be able to improve them.

Of course you don't have to believe me... good luck with this idea.


CT, I believe every word you say, I know there's a 99.9% probability that you're right, I raise these various hypothises for discussion as there is NOTHING on this earth that can't be improved on, in some aspect.

Otherwise we would all still be walking everywhere, living in caves, eating raw meat and banging two stones together for music.

Remember the worlds esteemed medical profession who were adamant that stomach ulcers were caused by faulty diets and ridiculed the Australian Professor who dared to suggest that they were caused by a certain type of bacteria. He was eventually proved correct and now the vast majority of stomach ulcers are easily cured by a course of specific antibiotics.

Or US paratroopers during WW2 who were taught to land with their feet apart and suffered a higher rate of ankle injuries than British paratroopers, who were taught to land with their feet together in conjunction with a landing roll that transfered the impact force up along the outer leg across the buttocks and back, the continuation rolled them back onto their feet again ready for action.

Some of my ideas are dreams, some wistful thinking, but SOME may be useful alternatives, so when I post them for discussion don't take them too much to heart.

The world is full of people with fixed ideas, who because they carry out a task a certain way, there can be no better way to do it and couldn't tell a good idea from a poor one, not even if it jumped up and bit them on the backside.

I daresay the only reason Stradivari didn't use bandsaws, finger planes, sandpaper or Dremel tools, was that they hadn't been invented.

I don't want to be in that class of people, I hope I continue to think of alternative ways to do things until the day I die.

Incidently, this thread, as you are aware, flowed on from the one (on another Forum) where I was trying to work out the best method to stop a sound post slipping on aluminium plates. I have today thought of a very simple solution that doesn't require any type of friction patch or retaining rail glued to the plate. Which I am by now aware, may slightly subdue the sound, have tried it out and it works flawlessly.

I won't tell you what the solution is, at the moment, other than to say it is very simple, to see how long it takes to come to your mind as well, now that you know there is a solution, as you too have an inquiring mind.

When I start an idea in my mind, they tend to flow in many directions and sometimes in the middle of them all a sudden solution will come to mind.

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My guess is a tiny round piece of sandpaper glued to each end of the sound post?

My previous posts were not an attempt to seek to dissuade you from innovating, but an attempt to save you some time and effort. In all the examples you gave, I would guess (without knowing) that those improvements were made by people who were not new to the field, but by people who had enough experience to understand the problem correctly to begin with.

Even so wrestling with an innovative concept can do nothing but force you to learn anyway, so, It doesn't really matter what I think, it's not me doing it and it won't be me that learns from the experience. Not long ago I attempted to learn an "innovative" plate tuning process which I discovered was not really workable - however, that's not to say that the experience wasn't valuable or that I didn't learn something from it.

This weekend came and went too fast, I'll really attempt to formulate the rest of that reply on the String Asylum by tomorrow evening, it's three quarters finished.

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"My guess is a tiny round piece of sandpaper glued to each end of the sound post?"

That's one idea that never occured to me, it would probably work very well, I knew you had an inquiring mind and could come up with some wonderful ideas when the need arises.

The solution is much simpler, it's as follows:

Use a sharp edged instrument (chisel) to score lines in the soft aluminium, on both plates, in the area where the sound post will be fitted, parallel to the centre axis.(like mini plow furrows)

The lines need to scored with the raised edges facing "uphill" to act as restraining anchors, these sharp edges sink easily into the end grain of the sound post, thus allowing full contact to be made with the plates for maximum vibration transmission and at the same time preventing the post from slipping "downhill".

My instruments of course have one major improvement on the old masters when it comes to fitting sound posts, if it gets to tricky trying to carry out what is, in effect, an endoscopic operation, it's a simple matter to remove the back plate, fix the post in the required position with some blue tack, screw the plate back on and remove the blue tack with a wire hook.

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I am in 100% agreement CTVIOLIN. Anyone with an innovative idea for an improvement MUST first become entirely familiar and understand current and accepted methods. However,I do feel he/she is entitled to have those innovative ideas during the learning process. I was merely trying to encourage Alex, and point out that Stradivari, too, was an innovator and an experimenter.

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