Sound post shifting

June 16, 2009 at 04:45 PM ·

I just got back from a luthier. He pointed out how the sound post has shifted toward the f hole pushing the upper plate. There was a visible bump! This is a new sound post. Our previous luthier thought the old one was a bit short and cut a new one last September. Although I didn't look, I am quite sure it was installed at the right place. How could it have moved to the side pushing up the upper plate on its own? 

Replies (24)

June 16, 2009 at 05:12 PM ·

I'll take a guess:  The violin's sound post takes quite a bit of vibrating, add on top of that, the violin body exspands and contracts with humidity and temperature changes.

June 16, 2009 at 08:07 PM ·

Well, I don't know. If it comes from settling naturally by vibration or expansion, it would shift to somewhere that's roomier, I would think. The sound post in question squeezed in to a tighter spot pushing the plate up.  Could it have been dropped? It is fixed for now. What I would like to know is if it could do that again under certain circumstance. It could have left an imprint or even cracked the top or bottom plate. Scary thought.

June 16, 2009 at 07:50 PM ·

Very similar thing happened to me. Humidity shot up, and a couple of seams opened, and the soundpost shifted. Apparently it's been happening to violins all over the city. Such finicky things!

June 16, 2009 at 08:44 PM ·

Generally, soundposts won't move on their own unless all the strings are released, there is a severe impact, things are coming unglued in a major way, or the violin has a very unusual arching which is peaked in the center. In the last case, the soundpost would move toward the center.

Is it possible that your luthier wasn't suggesting that it had moved on it's own, but that he didn't agree with where it had been placed?

June 17, 2009 at 01:19 PM ·

David, Thank you for the reply. That's exactly what I needed to know. You are right that the luthier didn't say it moved on its own just that he didn't agree with where the post was placed. The post was newly installed last September by another reputable luthier who I am sure put the post on the right spot. It is not that hard to get that right, is it? So I assumed that the post must have moved on its own some time since September.The violin is of a standard shape as far as I know. I change strings one at a time. The only mishap I had was when a store sent me a 3/4 G string. Before I realized that, I tried hard, very hard to tune. That couldn't have distorted the violin enough to move the post, could it? Would it be more likely that someone dropped the case at some point with the violin inside? It's my daughter's violin and she takes it to school.

June 17, 2009 at 01:35 AM ·

The post should fit snugly, but not tightly.  If your daughter is like mine (9yrs age), the violin will take a beating at school.  Many student grade violins are fitted tightly, to ensure the post does not jar loose during rough handling. The indication is a rise in the top plate when viewed from the side.  Not good for the wood, but then student violins are not intended to last forever.  But, you do not want to see more rise than 2mm max.

Humidity is the enemy for wood, causing it to swell.  For furniture, this means the dowels get crushed, so when the air is dry again, the dowels are loose.  This is why old furniture conmes apart and can't be reglued: larger dowels are then needed, and the cycle repeats.  For violins, not so much of a problem, as the sides will swell too, thereby raising the top and belly slightly, so no crushing. 
But the unknown factor is how much humidity the soundpost will absorb. If more than the sides, the SP will create pressure on the plates, causing an indentation, and the top plate will rise slightly. Removing the humidity can cause the SP to fit looser, and so it can slip free should the strings snap loose.  Usually, not a problem, as the strings keep everything under tension, so the whole violin holds together.

I live in Shanghai, where the humidity is so heavy some summer days, we are in a fog.  In winter, very much drier.  To avoid problems, I have moved my SP say 2mm towards the bassbar.  No problem during summer usually, but on occasion during winter should the strings jar loose, the SP can knock over when transported.  Resetting the SP is certainly a frustration, but in my case a looser fitted SP saves the violin.


June 17, 2009 at 04:39 PM ·

Although my daughter takes it to school, it's not a student violin. It will be a major loss should something happen to it. I don't believe the post is necessarily tight fitting. When the same post was placed at the right spot, the violin sounded far more open. I am beginning to think it calls for a more protective case.

June 17, 2009 at 01:39 PM ·

When we move a soundpost, we tap it with a setting tool. It usually requires a pretty sharp tap. Soundposts generally do not move on their own unless they are too short, or, as I suspect might be a contributing factor in your particular case, the top of the post is over-rounded. Then there is little friction between the top of the post and the belly, and even an unnoticed jarring of the case with the violin inside could, in very specific cirimstances, shift the post. However, as I think David mentioned, the movement would be toward the center. The presence of a bump is a sure indication that the post perhaps doesn't fit well and that it has been pulled too far outward with the setter. It's only when things like this are out of whack that humidity can exacerbate the problem. The bump worries me: it's time to have someone look at that post again.

June 17, 2009 at 02:06 PM ·

David, Thank you for the reply. That's exactly what I needed to know. You are right that the luthier didn't say it moved on its own just that he didn't agree with where the post was placed. The post was newly installed last September by another reputable luthier who I am sure put the post on the right spot.

I'm not sure but by "right spot" do you mean there's a definitive spot for where the soundpost should go on all violins? I had thought that it was a matter of taste - two different luthiers may place the soundpost at two different spots on the violin depending on their tastes (and yours, if you have given input). So Luthier A thought the post was too short for where he wanted to place it, and Luthier B thought it was too long through a combination of it truly being too long but also that he wanted to move the post to a different spot? I think that's what David meant when he said that Luthier B "disagreed" with the placement.


June 17, 2009 at 02:08 PM ·

We are getting it fully serviced in August. In the meantime, the post is set right for now. The bump is gone and the top seems to be settling back. Our last luthier mentioned something about the previous sound post cut at an angle. He didn't agree with that for some reason and put a new one in. Could there be something peculiar about this violin? From outside, i don't see anything. It's a Gustave Bernardel. 

June 17, 2009 at 02:54 PM ·

well, not qualified to say much, but here is a bit...

not saying that you should, but if you want to, you can have a good view of the inside of the violin by looking into the endpin hole (with the endpin taken off of course).  if you don't have a great lighting source, on a sunny day next to a window, there is enough illumination for the light to shine through the F holes while you look into the endpin hole.  you can appreciate a lot of wonderful things: the shape and length of the bassbar, the neck block, the liners, the wood, a fuzzy dirt ball or two, etc and of course, the upper and lower contact areas for the soundpost.  you should be able to see if the bevels of the post really neatly nudge onto the upper and lower table.  having said that, considering that you have to loosen all the strings, there is a chance your post will fall,,,so don't do it, but just a thought for a future tour.

i am not in a position to comment on whether the upper plate is too thin,,,i can imagine if enough force is applied a thick plate can bulge too.   what we all dread is that line of crack,,,the pressure from the buldge could contribute to that if other conditions of the freaks of nature are met.

IF a post is set too tight, or becomes relatively too tight (comparing to the height of the soundbox, since different woods may react to moisture differently)  because somehow the humidity induces a relatively longer post, it may get stuck on that spot, the original spot,  like a tire jack.  unless there is clear marking where the old post was set, to say that the post actually moved toward the treble side against higher pressure by itself without outside intervention does not really make sense.  

i wonder if luthiers can comment on the quality of the wood to be used for soundpost.  does soundpost wood need to be "aged" for stablility? 

June 17, 2009 at 03:24 PM ·

I'll try to respond to some of the question which have come up since my last post.

First of all, there probably is one best soundpost location for a given instrument, with a given player, in a particular season. This can change with time and playing though.

Luthiers will not all agree on where that best position is. They might not want to spend the time (or you might not want to spend the money) for them to experiment enough to find it. Or they might not know how to find it. They might choose a location based on whether it "looks right". Others have a set of measurements they use.

One example how things can easily get messed up: My own violins require that the soundpost be rather far back from the bridge, because I make the top unusually thick in that area for durability reasons. One volin was brought to me recently because it didn't sound good after a "respected luthier" had moved the post. Apparently this luthier noticed that the post was rather far back, and "fixed it" without noticing that the change had really hurt the sound.

The thing you need to realize about luthiers is that absolutely anyone can hang out their sign and go into business. Some are extensively trained, and some have next to no training. Even among those with extensive training and experience, there can big differences in skill at manipulating sound. There are a few who have developed a strong enough reputation that musicians will fly in from all over the place for a sound adjustment, or orchestras will fly the luthier in. Some luthiers aren't interested in that kind of business, so don't take that alone as an indicator of quality, but it will give you some idea of the disparity.


"I wonder if luthiers can comment on the quality of the wood to be used for soundpost.  Does soundpost wood need to be "aged" for stablility? "

One shouldn't use green, unstable wood of course. Regarding quality of the wood, opinions will vary.

Rene Morel has this trick he's pulled on musicians who got on his nerves when they insisted in some obsessive-compulsive way that only a certain kind of wood should be used. He makes a new soundpost, hands the violin back to the player, and asks, "How does it sound?" After they say that it sounds great, he asks them to look inside. What they see is that the soundpost has been made out of a pencil.  :-)

June 17, 2009 at 04:46 PM ·

People may disagree in fine adjustments but don't they agree in gerneral that the sound post is placed where the top is flat? It certainly couldn't be where the top slopes down forcing the post to push up the plate. We weren't doing any fine adjustment. I was there for evaluation how much work will be need when the luthier noticed the tiny bump. The sound opened up immediately when he teased the sound post to the flat part to ease the bump. It looked pretty basic to me.

June 17, 2009 at 06:53 PM ·

flat is relative.

June 17, 2009 at 09:22 PM ·

Ihnsouk, I'm not sure what you mean by the "flat part of the top". As a general rule, the soundpost goes behind the treble bridge foot (in the direction of the tailpiece). In practice, some violins can sound best with the post inward or outward from this position. If this is done, one must weigh the tonal advantages against possible negative structural consequences.

June 17, 2009 at 11:53 PM ·

I meant where the arch eases up a bit toward the middle, roughly the area under the bridge. The bump due to the post was behind the bridge toward the tail piece and a little outside of the foot. This sems to agree with the general area you mention for the post except it is placed a little outside of the bridge. If it was meant to be there, it should have cut shorter, I would think. I assumed that it was meant to be behind the bridge foot and cut accordingly but moved.

June 21, 2009 at 04:53 AM ·

no kidding... does a pencil for a SP really work?  

also, no kidding.... I saw a violin once that had the SP positioned in front of the bridge.  the owner said he preferred the sound this way.  


June 21, 2009 at 02:36 PM ·

Good question Ron:

If this is true, more than likely it was a regular ceader #2 soft graphite core.  Just for kicks & giggles, how would a harder graphite lead affect the sound?

What would a pencil for a sound

June 22, 2009 at 08:41 AM ·

"no kidding... does a pencil for a SP really work? "


 "What would a pencil for a sound"


I've never tried it myself. In this case,  Rene Morel was just trying to prove a point. He's quite a character. If he thought a section of pencil was actually acceptable, he'd probably use it on a regular basis, which he doesn't.

Once in a while, you get a customer who is obsessed with some trivial thing or another. They won't believe what you say, so you need to demonstrate. ;-)

In this case, I don't thing the message was that a pencil is acceptable, but that what a luthier does with the soundpost is more important than the material. In actual practice, Rene hand-makes soundposts starting with a raw, rectangular piece of spruce.

June 22, 2009 at 02:44 PM ·

Bravo Rene! LOL!

June 23, 2009 at 08:29 PM ·

How much does Rene charge for a soundpost adjustment or replacement?

June 23, 2009 at 09:31 PM ·

You can probably call to ask -

June 25, 2009 at 07:23 PM ·

Someone told about a 'pencil' sound post. I know it is off-topic but how about this, a Cristal Sound Post?

I'm not going to install one of those on my violin though...


June 26, 2009 at 03:27 AM ·

How about a carbon fiber soundpost? ;-)

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