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Do Soundposts Drift?


GlennYorkPA
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Okay, while thinking about the whole soundpost drifting thing, I was finally tuning, shaping, tweaking a bridge on a violin that I finished two years ago. It has been played regularly and I was surprised to find the varnish mostly worn away under the bridge feet. So how does this happen? I've seen this on older instruments but I was surprised that this happened so quickly on mine. In reality, the tension on the feet should be about the same as the top of the soundpost against the top plate, shouldn't it? Are the bridge feet moving ever so slightly and wearing the varnish away? If it is, is it possible that the soundpost could be moving ever so slightly as well? I'm asking because I honestly don't know why the varnish wears. I'm assuming it's the vibrations that are causing it but maybe it's because I had a poor fit on the bridge feet to begin with or could it caused by movement simply from tuning? Anyway, the whole soundpost movement thing made me wonder about bridge feet movement.

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Okay, while thinking about the whole soundpost drifting thing, I was finally tuning, shaping, tweaking a bridge on a violin that I finished two years ago. It has been played regularly and I was surprised to find the varnish mostly worn away under the bridge feet. So how does this happen? I've seen this on older instruments but I was surprised that this happened so quickly on mine. In reality, the tension on the feet should be about the same as the top of the soundpost against the top plate, shouldn't it? Are the bridge feet moving ever so slightly and wearing the varnish away? If it is, is it possible that the soundpost could be moving ever so slightly as well? I'm asking because I honestly don't know why the varnish wears. I'm assuming it's the vibrations that are causing it but maybe it's because I had a poor fit on the bridge feet to begin with or could it caused by movement simply from tuning? Anyway, the whole soundpost movement thing made me wonder about bridge feet movement.

Kubasa,

Are you sure the varnish wore away under the bridge feet or did it just stick to the bridge and was lulled away when the bridge was removed?

I'd like to believe that all the vibrations transmitted to the body through the feet degraded the varnish but I remove the chin rest from every violin that enters my collection and always find damage to the varnish at the point of contact.

Violin varnish is quite tender, especially oil varnish and anything pressed onto it for an extended period will bond to it.

Glenn

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I don't need to "convince" you or anyone else; as a maker, you're welcome to your own separate reality. As a player, I know what's been experienced not just by me, but also by 50 other professional string-playing colleagues.

Being the nudge I am, I simply don't like to see mis-information spread around via the Internet. You get a pimple on your butt in New York, the next day everyone in LA knows you have pneumonia.

Besides, if "they already agree with the opinion", any attempt at "convincing" would be redundant.

Hmmm, that's quite a Gordian knot you've tied there.

The fact is, that anyone - you - me - anyone else -, has an opinion formed by their unique individual experiences, and no on can say that they (you, or I, or even the other guy) must or should change their opinion or observation, based on the fact that someone else might have a different opinion or even a different worldview.

I don't understand it when someone has an opinion that they insist is truly the (perhaps only?) correct one.

You've talked to fifty professional string players? I've talked to at least as many, and in addition - hundreds of violin makers and repairmaen. Still - neither of us can claim irrefutibly, that we are absolutely correct about a point such as this.

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There are several different issues in this thread, all interesting!

It's a well observed phenomenon that if you relax the tension by slackening the strings and then retension everything, it will take 24 hours to settle down and sound like it sounds. So the success of any modifications which involve taking the bridge down can't really be judged the same day. In my experience it can go either way, sounding significantly better or significantly worse the next day!

Most soundposts are shoved in far too tight, and take a bit of effort to dislodge, even with the strings down. Any change of position is likely to mean that the soundpost is a bit looser, so when you tighten everything up again you have subtly changed the arching, as well as inducing a new degree of tension in the table which may relax very quickly ....

The difficulty of judging one violin against another is a whole other can of worms - I'm afraid I think it's like marriage. You have to make the commitment!

Moving serially from one violin to another results in a chain of adverse comparison, and some players get stuck in that for life, always wondering if this one is "the one". When you move rapidly from one instrument to another you're mainly hearing the differences, not the reality. I think it's best to stop listening to the violins and just be aware of whether you're making good music.

Sometimes you make the best music on a violin whose sound you don't completely approve of, but that's the instrument to hold on to.

Sell all the others and start playing. Life is short.

Martin Swan Violins

Thank you, Martin; you've taught me how to live. Great post.

S

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... I was surprised to find the varnish mostly worn away under the bridge feet. So how does this happen? I've seen this on older instruments but I was surprised that this happened so quickly on mine. In reality, the tension on the feet should be about the same as the top of the soundpost against the top plate, shouldn't it? Are the bridge feet moving ever so slightly and wearing the varnish away? If it is, is it possible that the soundpost could be moving ever so slightly as well? I'm asking because I honestly don't know why the varnish wears. ....

Is it worn, or displaced? Glenn's points are the most obvioust to me. Unusual warmth this summer has caused quite a few problems in some states.

It may depend on the player, but students can strike/bump a bridge and think nothing of it. They'd re-tune the violin and keep playing. At the lesson the instructor would re-center the bridge.

The bridge, depending on the thickness and stiffness, rocks forward and back. I would think that this action would "wear" the varnish faster than the side-to-side (which you did not suggest). If the island is thicker, the arching would not distort that much on lower notes, but I can imagine on thinner islands that the bridge and top are not fully coupled during very active playing. I have certainly seen the "flattening" (displacement) of varnish under quite a few recent Italian instruments.

This also brings up the issue of shoulder rest feet, as they will remove varnish too, but for more obvious reasons.

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Yes, Bairoin you make good observations and personally I must say other fine players have reported this type of experience to me with violins in particular... even with top end old Cremonese instruments that have been great until half way during a concert some time when they become muddy. ( in fact the grade of instrument seems not to matter) I think that the micro climate of an orchestra or around a soloist can become quite humid. The breath onto the bridge and into the F holes I believe has some effect here as can an increased level of perspiration associated with the effort of performance in some players. This is something to be considered in making and set up.

Mr Goldsmith, thank you for your reply. It's taken me a day or to figure out how to respond.

Because the effect is often temporary, humidity would be ideal suspect, as the timeline and proximity to the instrument appear to coincide (related to my experiences). Will have to think about this some more. Trying to think of an occasion and instrument where this had occurred in a shop. I appreciate the posting of your comments. Thank you again.

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Kubasa,

Are you sure the varnish wore away under the bridge feet or did it just stick to the bridge and was lulled away when the bridge was removed?

I'd like to believe that all the vibrations transmitted to the body through the feet degraded the varnish but I remove the chin rest from every violin that enters my collection and always find damage to the varnish at the point of contact.

Violin varnish is quite tender, especially oil varnish and anything pressed onto it for an extended period will bond to it.

Glenn

Good point Glenn. I thought I had checked the feet but now, I can't remember if I did or not (so let's assume I forgot....) That makes sense along with the other comment about this being it hot, humid summer. It's quite possible that the varnish was indeed sticking to the feet. It just really surprised me when I took the bridge off because as I mentioned, I've seen that on older violins but I didn't expect it on mine. So, the logical answer here would be that my varnish was stuck to the feet because of the very hot, humid summer. It makes sense instead of somehow thinking that it was caused by drifting or creeping like this discussion started out. Okay, sorry for the detour and back to the discussion at hand!

Thanks - James

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As to the issue of any "soundpost drift" -

Here's an interesting experiment:

-

1. Pick a violin you like and know

2. Play for 15 minutes, at least till you feel warmed-up

3. Now put on your mute and repeat #2

4. Finally, take the mute off, and play again.

Ask yourself, does this third sound differ from what you experienced during the first 15 minutes?

And why?

i'll be really curious to hear your answer to that last question, if you don't mind

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If the back has been sealed and burnished and the post has been moved around a bit and therefore burnished those surfaces can get pretty slick. So I think it is possible that the post can move. But I agree that it's not very likely if string tension has not been changed.

Oded

Agree with one caveat. A new violin that hasn't been brought back for a 6 month check up can have the soundpost wandering about as it is a bit loose and little jars can make them walk.

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I had a young viola customer who kept coming back to me with the soundpost down. I was feeling a little exasperated, as I knew that post had been quite snug. Finally I noticed that this kid was pretty big, and had big hands. I asked him, "Are you picking this instrument up like this?" (demonstrating with my thumb and fingers spanning the center bouts.) He cheerfully admitted that he was. I explained that he was strong enough that he was flexing the plates, and making them release the SP. ("Doctor, it hurts when I do this... " "Don't do that!")

I set the post one more time, and the instrument never came back. Nice kid. Just had no idea what he was doing to the viola. :)

...I have a bad habit to break, apparently.

Certainly explains the inconsistency of my viola when I was teaching regularly-and resting the instrument on my hip while holding it in exactly that manner.

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Agree with one caveat. A new violin that hasn't been brought back for a 6 month check up can have the soundpost wandering about as it is a bit loose and little jars can make them walk.

Dean,

Much earlier in the thread, someone suggested marking the position of the post with a pencil then looking to see if it had moved.

My point in starting this thread was to find out if anyone had actually done this and it appears they have not and so we have had an interesting theoretical discussion about whether posts might move to their sweet spots or not.

So I'm fascinated that you now say you have clear evidence for walking posts following new set up. If the movement had an improving effect on the performance of the violin, I would take that as support for the proposition.

Glenn

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Much earlier in the thread, someone suggested marking the position of the post with a pencil then looking to see if it had moved.

My point in starting this thread was to find out if anyone had actually done this and it appears they have not..

I have. As I mentioned before, I've only run across a couple of instances where reasonably tensioned and fit posts seemed to move on their own, from nothing more than playing, and these were unusually arched instruments. I can't be positive this was just from playing though. Can't rule out other things that the owner declined to mention.

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Much earlier in the thread, someone suggested marking the position of the post with a pencil then looking to see if it had moved.

My point in starting this thread was to find out if anyone had actually done this and it appears they have not and so we have had an interesting theoretical discussion about whether posts might move to their sweet spots or not.

So I'm fascinated that you now say you have clear evidence for walking posts following new set up. If the movement had an improving effect on the performance of the violin, I would take that as support for the proposition.

Glenn

Yes, I suggested that. (the pedant)

But, from your original post, I had not gotten the implication that perhaps you thought that the post might "drift" in order to find it's particular “sweet spot“. I believe that it may have been implied, but not stated directly.

In any case, I missed it.

My guess would be that it (the sp) might drift at times, due to something improper - a sharp blow - tp gut broke - the bridge fell - string(s) broke - abrupt curves or short post, and on and on.

But in any case I would think that the movement might be random.

The idea that it might seek out its own "sweet spot" by some means of some physical inclination, just doesn't seem likely to me.

For one thing, in order to theorize, I do not believe that there is a stable or consistent nodal line in that position - which, under certain circumstances (like, if the violin was played loudly and continuously at one single frequency and receive a sharp blow...) might cause the post to wander to a specific spot having to do with tone..., exists.

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Dean,

Much earlier in the thread, someone suggested marking the position of the post with a pencil then looking to see if it had moved.

My point in starting this thread was to find out if anyone had actually done this and it appears they have not and so we have had an interesting theoretical discussion about whether posts might move to their sweet spots or not.

So I'm fascinated that you now say you have clear evidence for walking posts following new set up. If the movement had an improving effect on the performance of the violin, I would take that as support for the proposition.

Glenn

Hi Glenn,

I have not seen "walking posts" in properly fit seasoned violins. Most violins gain in arching height after construction, as you know...I think the walkers were due to a lack of a new post that accommodated the new arch AND abuse while in the case. BTW I need to send a pic of a wooden case while I still have it. Not ornate but interesting. I'll PM you.

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Yes, I suggested that. (the pedant)

But, from your original post, I had not gotten the implication that perhaps you thought that the post might "drift" in order to find it's particular “sweet spot“. I believe that it may have been implied, but not stated directly.

In any case, I missed it.

My guess would be that it (the sp) might drift at times, due to something improper - a sharp blow - tp gut broke - the bridge fell - string(s) broke - abrupt curves or short post, and on and on.

But in any case I would think that the movement might be random.

The idea that it might seek out its own "sweet spot" by some means of some physical inclination, just doesn't seem likely to me.

For one thing, in order to theorize, I do not believe that there is a stable or consistent nodal line in that position - which, under certain circumstances (like, if the violin was played loudly and continuously at one single frequency and receive a sharp blow...) might cause the post to wander to a specific spot having to do with tone..., exists.

CT - I never got into the vibrational analysis of violin plates so I'm interested in your comment about there not being a nodal spot or line where the sound post is. My simple mental image was that the purpose of the post, in conjunction with the counter pressure from the treble foot of the bridge, was to create such a nodal point. If you are correct, then the top is flapping about as much at the post position as anywhere else and there is no point of rest for it to migrate to. I pictured an island of vibrational tranquility where the post would prefer to be but I'm now seeing this model doesn't hold up. In which case, the improvement I notice is entirely due to me learning how to adapt to the setting. Thanks for clarifying this for me.

Glenn

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Hi Glenn,

I have not seen "walking posts" in properly fit seasoned violins. Most violins gain in arching height after construction, as you know...I think the walkers were due to a lack of a new post that accommodated the new arch AND abuse while in the case. BTW I need to send a pic of a wooden case while I still have it. Not ornate but interesting. I'll PM you.

Hi Dean,

It seems the walking posts were more a figment of my imagination than reality.

I don't have much success with PMs so could you indulge me by sending the case pics to my email glennpwood@yahoo.com. I'm always looking for interesting examples of cases, preferably with provenance, for the second edition of my book.

Thanks

Glenn

www.violincasecollecting.com

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CT - I never got into the vibrational analysis of violin plates so I'm interested in your comment about there not being a nodal spot or line where the sound post is. My simple mental image was that the purpose of the post, in conjunction with the counter pressure from the treble foot of the bridge, was to create such a nodal point. If you are correct, then the top is flapping about as much at the post position as anywhere else and there is no point of rest for it to migrate to. I pictured an island of vibrational tranquility where the post would prefer to be but I'm now seeing this model doesn't hold up. In which case, the improvement I notice is entirely due to me learning how to adapt to the setting. Thanks for clarifying this for me.

Glenn

It all depends on what frequency you're interested in. At A0, B1-, and B1+, the post is pretty much on a nodal line. But not the CBR... the post moves for this one. And at many other frequencies, the post is moving... i.e. NOT on a nodal line. And at some frequencies, it IS at a nodal line. No simple answer (as usual).

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It all depends on what frequency you're interested in. At A0, B1-, and B1+, the post is pretty much on a nodal line. But not the CBR... the post moves for this one. And at many other frequencies, the post is moving... i.e. NOT on a nodal line. And at some frequencies, it IS at a nodal line. No simple answer (as usual).

Don,

Thanks for the comment.

Do those frequencies you refer to (A0 etc) correspond to low notes or open strings?

In my experience, the settling in of the post (or my adaptation to it) happens quickest with hard playing on the open strings and it's usually the G and D that need most help.

Thanks

Glenn

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Lower frequency body vibration modes. See these definitions... although it's a bit out of date (B1 is really two relatively closely spaced modes, thus the - and +).

Now you've lost me again.

I can understand Martin Schleske's wobbling plate videos where you can clearly see what's happening but this table is just hocus pocus for me.

Thanks anyway.

Glenn

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