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Why sound post fit matters


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I don't know why the fit is important for sound, I just know that it is.

 

I don't believe you, Mr. B  :-)

 

 

A poorly fit post WILL fit eventually. See linkman's post. The top will fit to the post! Also the load will distort the top to fit the post. Seen that plenty of times! These are reasons enough to fit the post well.

Tension will also fit over time! Too tight or loose will eventually settle in. The arching will distort off course but it will all work out.

 

The only remaining question is: do you really want that to happen? Nobody should want their instrument to distort in any way if it could be helped.  But that doesn't make the facts less correct here.

 

I feel the largest factor in the fit is this: do both ends of the post have exactly the same amount of wood touching (and at the same amount of tension throughout).  Let's say they don't:  then there is a large part of the post that is simply not reacting the same as the rest.  Same with position, n-s and e-w both.  If you move it off of optimal position by 1/10 mm, the difference in tone, response, and power is gargantuan.  I agree with Curious1 in that position is more important simply because this will not 'settle in'.  It's either executed correctly by the luthier (or amateur...) or it isn't.  However, while a post may settle in with a bad fit, that still doesn't guarantee that the contact will be exactly the same on both ends of the post, no matter what amount of time is given.  Or that the tension will be equal across the plane of contact.

 

Only with a good initial fit can you ensure the longevity of the health, tone, and response of an instrument.  There's no reason to shoot for anything else, really.

 

The real question is HOW to make a perfect fit that maximizes the instrument's sound.

 

Ouch.  Ain't that the painful truth.

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The thing I noticed about Evahs is that they stretch a lot, especially around the bends in the nut and bridge.  When they stretch, the metal windings develop gaps... like saw teeth.  That can't be good.

 

Evah A strings especially... I don't know how many I have had unwind.  But that was also due to my slacking and tightening them during adjustments.  They (the A string) don't usually unwind if you keep them tuned up after the first time.  Never had many problems with the others unwinding totally.

 

 In the case of seasonal variations, NY has pretty severe climatic changes, I'd be surprised if no one ever changes bridges, but it pro'ly depends also on the model.

 

Or if they don't control the humidity in their home..

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On another note, I took a peek at my teacher's violin (Januarius Gagliano ca. 1756).   I had never looked at the post before... and found that it is not even verticle.  Not north-south OR east-west.  The ends look like they are fitted well, but... what's the point??  Gotta get the other stuff right, too.  That's why a true perfect fit is so darned difficult.

 

Oh, and it was set up by one of the most prominent shops in the country.....

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On another note, I took a peek at my teacher's violin (Januarius Gagliano ca. 1756).   I had never looked at the post before... and found that it is not even verticle.  Not north-south OR east-west.  The ends look like they are fitted well, but... what's the point??  Gotta get the other stuff right, too.  That's why a true perfect fit is so darned difficult.

 

Jesse; Who says the other aspects are "not right" for that fiddle?  As a friend once said to the Oberlin Workshop participants about working on historic instruments (paraphrase); "Keep in mind you probably aren't the first genius to work on this (any) instrument".  It may well be that the new post was cut to fit a spot that an old post, that was once quite successful, was positioned. Gotta' heed those with good hands who have gone before you before you can even hope to make an improvement... if one is possible.

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On another note, I took a peek at my teacher's violin (Januarius Gagliano ca. 1756).   I had never looked at the post before... and found that it is not even verticle.  Not north-south OR east-west.  The ends look like they are fitted well, but... what's the point??  Gotta get the other stuff right, too.  That's why a true perfect fit is so darned difficult.

 

Oh, and it was set up by one of the most prominent shops in the country.....

Adding to Jeff's comment, the positions of the top of the post and the back of the post do different things. It is not at all odd to have the post not vertical.

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Now I'm getting confused.

 

I guess I've always assumed that a vertical post is generally best. And that usually if a tilted position seemed good, it meant that the length/tension needs attention.

 

Things I think are happening in setting a post:

 

'Good Fit' means clean flat post ends at just the right tilt to evenly distribute contact on both top and back.

Inspect with a light and mirror to see clean contact with plates all around post

'pivot' the post in place to feel a good fit

Fit is essential for sound, power, response, bright tones..

 

Position adjusts tonal balance and character

Starting position is centered behind the treble bridge foot, which ideally is also symmetric to bass bar

Starting position is about half a post width behind the bridge foot

To adjust bass to treble balance, move nearer or farther from bar

To adjust tightness/hotness of response versus openness/fullness of tone, mover nearer or farther from bridge

This aspect also interacts with after length.  Short for tighter, longer for more open

Position is in terms of the post contact with the top.  Within normal ranges, position of contact with back does not have similar tonal results.  However, the resulting change of tension can and is significant.

 

Tension/Length is critical for power and response of tone

Tension is creating a balance between the plates and strings. 

The tension balance is changed by any of:

Post Length

Post tilt

Post position

Bridge height

Tension of strings chosen

Pitch level of tuning

Post tension is mostly manipulated through post length. This has to be set fairly early in the setup process, but then all the later elements of setup impact the tension balance.  So, post length likely needs to be revisited after all else is done.

 

? A tilted post position will be a bit like a poor fit in that it adds an indirectness of action between the top and back????

 

These are the things I think I see.  But then I'm prone to imagining stuff.

 

Thoughts?

 

 

 

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I don't have an answer yet. Maybe I'll look into whether some of the synthetic materials used for guitar nuts have better wear properties than ebony. Anybody know?

 

A lot of the synthetic materials for guitar nuts are easy to abraid with wound strings. They are probably a bit harder to wear than ebony, ebony is seldom used as a guitar nut for that reason. The synthetic materials like Tusq, Micarta or Delrin can also be very different, the problem is you have to try the to see if they sound good. Personally I don't think Delrin is a good nut material because even though it is tough, it does not "feel" right in terms of how it stops the string at the break angle point. Oddly enough the nut adds a bit to the quality of the sound, without going really deep into it, the neck of a guitar produces a bit of the sound in an acoustic-classical guitar and as many of you know the species of wood used in an electric guitar neck is a tonal contributing factor. Electric guitars often employ a metal nut, brass for example, one reason is to effect the tone and the other is because electric guitar strings are nut cutters. Lots of makers use bone as the standard in acoustic guitars both steel and nylon string. Corian, Micarta, Tusq are cheap to buy from guitar supply houses to test durability, they can be had in black, but I don't use them on guitars, them might work for violin nuts. 

My favorite nut is good ivory, but I gave up my stash for various reasons, I use the best bone I can get.

 

My thought for that raspy and cutty violin A string would be to use an ebony nut with a bone insert for the A slot. The bone can be morticed into an ebony violin nut blank and super glued, doubt it would come out. Then the nut would be fitted, slotted, polished etc and then the bone can be dyed black with a black Sharpie marker, or with a spot of analine dye...whatever..then a dab of shellac to give it the same sheen as the ebony..you know how to match textures. I bet it be worth try if the ebony gets worn down to the the fingerboard by those aggressive A strings. 

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I don't believe you, Mr. B  :-)

 

 

 

The only remaining question is: do you really want that to happen? Nobody should want their instrument to distort in any way if it could be helped.  But that doesn't make the facts less correct here.

 

I feel the largest factor in the fit is this: do both ends of the post have exactly the same amount of wood touching (and at the same amount of tension throughout).  Let's say they don't:  then there is a large part of the post that is simply not reacting the same as the rest.  Same with position, n-s and e-w both.  If you move it off of optimal position by 1/10 mm, the difference in tone, response, and power is gargantuan.  I agree with Curious1 in that position is more important simply because this will not 'settle in'.  It's either executed correctly by the luthier (or amateur...) or it isn't.  However, while a post may settle in with a bad fit, that still doesn't guarantee that the contact will be exactly the same on both ends of the post, no matter what amount of time is given.  Or that the tension will be equal across the plane of contact.

 

Only with a good initial fit can you ensure the longevity of the health, tone, and response of an instrument.  There's no reason to shoot for anything else, really.

 

 

Ouch.  Ain't that the painful truth.

I guess I wasn't clear enough. At the MINIMUM a post has to fit and be at the correct tension but it isn't right until it is in the right place. Poor tension and fit will work themselves over time will work themselves at the detriment of the instrument.

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Jesse; Who says the other aspects are "not right" for that fiddle?  As a friend once said to the Oberlin Workshop participants about working on historic instruments (paraphrase); "Keep in mind you probably aren't the first genius to work on this (any) instrument".  It may well be that the new post was cut to fit a spot that an old post, that was once quite successful, was positioned. Gotta' heed those with good hands who have gone before you before you can even hope to make an improvement... if one is possible.

Exactly. Each instrument is different.

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This is another of those subjects about which there is more bull shit flying about, than there is at a Texas rodeo. I am always skeptical of posts that are not vertical. It often indicates that the post is digging into the back and belly unevenly, causing damage. There are three important things about posts; these are fit, position and tightness. Of these, tightness is the most important for the sound. The post should always be tightened equally top and bottom.

This is followed by position. Initially, on new instruments or instruments that have been apart, I almost always fit a violin post about two millimeters inside the bridge foot. (Higher arched instruments require slightly less). And half a sound post width behind the bridge. This is to allow for movement as the instrument settles. With just a new post in a settled instrument I fit it one millimeter inside to allow the post some compression. After a month or so the post can either be adjusted or shortened. 

As a very general rule the closer that you go to the bridge the more direct (focused) the sound becomes, until it begins to get muted. The further behind the bridge you go, the better the response becomes, until it begins to lose focus. I always insist that a post should be fitted with the sound post setter slot facing exactly outwards and the post vertical in all directions. This way you can always see if the post has moved or has been moved. This may mean fitting more than one post sometimes three for cellos.

The quality of the fit is all about the health of the instrument.  Of course all this is pure theory and things can be very different for each instrument and that is where the ear and experience comes in. Once the final adjustment has been done leave it alone. 

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On another note, I took a peek at my teacher's violin (Januarius Gagliano ca. 1756).   I had never looked at the post before... and found that it is not even verticle.  Not north-south OR east-west.  The ends look like they are fitted well, but... what's the point??  Gotta get the other stuff right, too.

If the ends fitted well, and it wasn't vertical, it's probably because someone found that the post worked well in that position, and meant for it to be that way.

Consider the wide variety of thicknesses and graduation schemes in various instruments. Why would the ideal post position on the back always just happen to be directly across from the ideal position on the top?

 

Like Holmes and Pasewicz, if I run across a crooked post on a fiddle which is working really well, I'll be very very careful about "correcting" it.

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Adding to Jeff's comment, the positions of the top of the post and the back of the post do different things. It is not at all odd to have the post not vertical.

This is another of those subjects about which there is more bull shit flying about, than there is at a Texas rodeo. I am always skeptical of posts that are not vertical. It often indicates that the post is digging into the back and belly unevenly, causing damage. There are three important things about posts; these are fit, position and tightness. Of these, tightness is the most important for the sound. The post should always be tightened equally top and bottom.

This is followed by position. Initially, on new instruments or instruments that have been apart, I almost always fit a violin post about two millimeters inside the bridge foot. (Higher arched instruments require slightly less). And half a sound post width behind the bridge. This is to allow for movement as the instrument settles. With just a new post in a settled instrument I fit it one millimeter inside to allow the post some compression. After a month or so the post can either be adjusted or shortened.

As a very general rule the closer that you go to the bridge the more direct (focused) the sound becomes, until it begins to get muted. The further behind the bridge you go, the better the response becomes, until it begins to lose focus. I always insist that a post should be fitted with the sound post setter slot facing exactly outwards and the post vertical in all directions. This way you can always see if the post has moved or has been moved. This may mean fitting more than one post sometimes three for cellos.

The quality of the fit is all about the health of the instrument. Of course all this is pure theory and things can be very different for each instrument and that is where the ear and experience comes in. Once the final adjustment has been done leave it alone.

It the ends fitted well, and it wasn't vertical, it's probably because someone found that the post worked well in that position, and meant for it to be that way.

Consider the wide variety of thicknesses and graduation schemes in various instruments. Why would the ideal post position on the back always just happen to be directly across from the ideal position on the top?

Like Holmes and Pasewicz, if I run across a crooked post on a fiddle which is working really well, I'll be very very careful about "correcting" it.

I would consider it a truly exceptional violin that sounded best with the post vertical.

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There are three important things about posts; these are fit, position and tightness. Of these, tightness is the most important for the sound. The post should always be tightened equally top and bottom.

This is followed by position. 

 

Well, I'll say that in 99 out of 100 violins (approx.), this holds true, so if you can achieve these variables you can fit any soundpost well.

 

Then again, I have found what David talks about also. As I have posted earlier in this thread.

But not often.

Often, very often, most often,  the ideal spots for the soundpost ends are opposite one another.

Why? Who knows. Perhaps the theoretical posters can ponder that the nth node is connected front and back then, or some such -

 

But, rarely a tilt can achieve the best tone, rarely that is, in my experience  also.

Actually, I even hesitated to mention this possible oddity in SP setting, way back in the beginning of this thread because it is rather an oddity. 

So is this correct thinking? 

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Like Jerry and David I would be extremely reluctant to move a post away from a position (not vertical) that is clearly marked on the back by a shiny spot, indentation, old pencil mark etc. That is to say historical precedent.

The post is there to regulate the modal behavior. Position is the most important.

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This is another of those subjects about which there is more bull shit flying about, than there is at a Texas rodeo. 

 

The quality of the fit is all about the health of the instrument.  Of course all this is pure theory and things can be very different for each instrument and that is where the ear and experience comes in. Once the final adjustment has been done leave it alone. 

 

I'm afraid I've never been to a Texas rodeo...  But Roger's last statement kind of says it all.  See below:

 

One of the documents that made an impression on me early on was a reprint of a very old technical drawing, by a maker, of a higher arched instrument.  The post wasn't vertical at all... the post, at the back, was noticeably closer to the center joint that it was at the top.  I can only assume the violin maker felt that was the proper position for the fiddle, very possibly due to the design and thickness of his arching.

 

Conversely, a couple years ago, a symphony player brought in one of Roger's fiddles that was purchased by a local violin collector through a dealer in NY.  The post was pushed toward the C bout edge at the back and was very tight (the upper treble ff wing was lifted very significantly).  It was reported to me that the previous owner loved it that way, but the symphony player nor I could get the violin to sound well when we tried to play it.  It sounded like a choked chicken (which I have heard, don't ask me why) and, with the exception of the post position and tension, neither of us saw a reason it should sound that way.  Two shorter posts later (allowing the wing to level out between installations), with the sound post very-close-to-if-not vertical, both the player and I were vary happy with the sound.

 

I always have a much easier time installing or adjusting a post in an instrument I already know well...  but if does occasionally take fitting more than one post to get things where I want them.  Just putting the second post in a Scarampella this morning.

 

As David, Curious1, Jerry and I have all mentioned earlier; It's a really a good idea to consider what's worked previously... but if it ain't working, it's often best to go back to the standard guidelines and start over.  Wherever you do put it in the end, for the health of the instrument and the stability of the adjustment, it's gotta' fit. :)

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If the ends fitted well, and it wasn't vertical, it's probably because someone found that the post worked well in that position, and meant for it to be that way.

Consider the wide variety of thicknesses and graduation schemes in various instruments. Why would the ideal post position on the back always just happen to be directly across from the ideal position on the top?

 

Like Holmes and Pasewicz, if I run across a crooked post on a fiddle which is working really well, I'll be very very careful about "correcting" it.

 

It might've also been fitted by an incompetent or worse, ...myself. :) And how would one know if it's "working really well" if one doesn't make 

changes, observes the results and "adjusts" accordingly.

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Something that's worked for me over a long period of time is to roll the top of the bridge, after the notches have all been finished, over a drop or two of CA glue. I put a drop or two of thin CA glue on a non porous surface and roll the top of the bridge over the glue then immediately roll the top of the bridge over a piece of paper towel. This way the CA glue stays in the grooves but most of the glue is removed from the edge. This procedure does alter the sound a bit but I like the effect- a bit more focused.

Same can be done with a nut. If the groove has worn then a mix of ebony dust a CA glue or just several layers of CA glue can be used to raise it up a bit.

I've seen a 75 yo bridge in good condition and someone recently reported seeing a viola of mine made in 1987 with the original bridge (both in excellent condition) The 'wings' of a bridge can sometimes settle so the ends of the knees should not be cut with an upsweep or the two surfaces can end up touching and ruining the acoustics of the bridge.

A bit of powdered rosin on the ends of the soundpost can help keep it from migrating.

Oded

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I was just wondering how you can get a soundpost to be tighter at one end than the other.

 

Easy, one end has a perfect fit and the other end has a less than perfect fit. The pressure (i.e., tightness) exerted at each end is proportional to the surface area of contact. Of course the force exerted at each end will remain equal.

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Easy, one end has a perfect fit and the other end has a less than perfect fit. The pressure (i.e., tightness) exerted at each end is proportional to the surface area of contact. Of course the force exerted at each end will remain equal.

I don't think that's what Roger meant. His post fits perfectly.

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