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Can anyone articulate their impressions of the effect of bassbar placement on sound?  I am trying to weigh the balance between my training and the oddly proportioned instruments that I often see.

 

What do you believe is the tonal effect of moving a bassbar further in, further out, or angled in some way other than the 1/7 proportion?  Also, mass and stiffness variations for that matter.

 

I had a stock of bridges in 1mm increments from 40mm - 44mm to try and keep the bridge centered while maintaining the proper overlap over the bassbar and came to the conclusion that a poorly placed bassbar should not necessarily dictate bridge width.  In theory a bar further out should get the wider bridge, but I have not found it to necessarily be the right choice.  I have also had better luck with bridges centered on the f-holes/centerline rather than shifting them off center to match the bassbar overlap.  

 

I imagine that the effect of mass of the bar is similar to effect of tightness of the sound post, and effect of moving the bar inward or outward is similar to moving the post inward or outward.  I can't say that I have documented enough bassbar details to have a clear picture of how an oddly placed bar effects sound.  

 

I think that understanding the effects of changes to the bassbar might better inform placement of a new bassbar that might be more specific to the instrument.  For example, a wider bar to add a little more mass to help get a stiff top moving?

 

The closest similar topic that I found was about 43mm and 44mm bridge placements.  A couple interesting points in there, but not quite what I'm looking for.

 

http://www.maestronet.com/forum/index.php?/topic/326383-43-and-44-mm-bridge-blanks-for-violin

 

As always, thanks for the feedback.

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This is definitely an interesting topic but difficult to answer. I tend to move the bar slightly further out on a weaker top and a little bit in on a stiff one ranging between 1 and 1/2 mm inside the foot. I also think centering the bridge is very important and if the instrument is worth it I would move the bar rather than set the bridge over. I have just made a fiddle with a taller bar to see what would happen and am not really impressed although my thinking was to make an instrument that would appeal to a really strong player and have been told that this one sounds better when played loud but I;m not sure if that is the same thing. In general I use the same bar dimensions on most fiddles and find that when I do change it's not easy to assess the result. I have heard different ideas on this from different people. I believe Carl Becker stuck to a set of numbers for each model but have heard from other good makers that they change as much as 2 mm in height on different instruments although I don't really understand what dictates the changes.  Hopefully some of the other folks will comment on this.

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This is definitely an interesting topic but difficult to answer.

 

Thus the lack of answers.  I have not heard any answers either, only "what I do, and it seems reasonable" type of things.  I don't have answers, either.

 

But the lack of clear answers says something.  Either hardly anything happens, or whatever happens is somewhat random and hard to pin down.

 

Extrapolating downward from my test where I removed the bass bar entirely, I'd guess the answer is both... hardly anything happens, and whatever does happen is hard to pin down.  Given that a bass bar of normali-ish size is used, I would think that slight position movements would be really tough to judge.

 

I'd just make sure it is mostly under the bridge foot, only to be sure that the F-hole wing doesn't cave in.

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This is definitely an interesting topic but difficult to answer. I tend to move the bar slightly further out on a weaker top and a little bit in on a stiff one ranging between 1 and 1/2 mm inside the foot. I also think centering the bridge is very important and if the instrument is worth it I would move the bar rather than set the bridge over. I have just made a fiddle with a taller bar to see what would happen and am not really impressed although my thinking was to make an instrument that would appeal to a really strong player and have been told that this one sounds better when played loud but I;m not sure if that is the same thing. In general I use the same bar dimensions on most fiddles and find that when I do change it's not easy to assess the result. I have heard different ideas on this from different people. I believe Carl Becker stuck to a set of numbers for each model but have heard from other good makers that they change as much as 2 mm in height on different instruments although I don't really understand what dictates the changes.  Hopefully some of the other folks will comment on this.

 

For my last two violins, I had my bass bars about 3-4mm higher than usual.  What happened was that the response was somewhat slow and the bottom end was lacking a bit.  After trimming them down, response and bottom end improved.  However, on one of the violins, a bit of power is lost whereas the other one gained power.  I still don't know what on earth is going on. :D

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Interesting. I have not tried any alternatives, just followed my training, which is pretty much the same as Weisshaar. I was taught that height = stiffness and width = mass. More mass in the bar will drive the bar harder as will a tighter post. I can't really articulate the final effect, but i was thinking that observations from a more broad group might help flesh out the concept a little better.

I imagine that one could do a mass experiment fairly easily with weighted plugs that would go into holes in the bassbar so other variables could be eliminated. Not so easy to isolate other factors.

I just finished moving a bassbar on an inexpensive factory violin. I soaked the joint so I could remove the bar intact and refit it in the proper location with minimal other changes. The bar had been 3.5mm inside a 42mm bridge foot with the bridge centered. I tried setting it up with an off-center bridge with a 1mm bar overlap, but that was not great either. I tried variations between, and a few different post positions before resorting to the bar. I think the new bar location had a similar effect to moving a soundpost from too far inside the bridge foot to a place where it is better balanced. It's still not a great sounding instrument, but it's better balanced. Not a violin worth spending a to. Of time on, but it got me thinking about the question of how to make deliberate tonal changes through changes to the bar

After many adjustments to instruments over the years I can often hear things like an out of place soundpost, but it's hard to articulate the sound that identifies this issue. I'd like to hone in on it, and do the same with other adjustments, such as the bar.

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I imagine that the effect of mass of the bar is similar to effect of tightness of the sound post, and effect of moving the bar inward or outward is similar to moving the post inward or outward.  I can't say that I have documented enough bassbar details to have a clear picture of how an oddly placed bar effects sound.

 

As always, thanks for the feedback.

 

Hmmmm, 

I'd have to think real hard on this point.

The soundpost tightness is a completely different thing, and has completely different effects, than anything having to do with the bass bar...

They must be approached separately and moving them does completely different things.

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Hmmmm, 

I'd have to think real hard on this point.

The soundpost tightness is a completely different thing, and has completely different effects, than anything having to do with the bass bar...

They must be approached separately and moving them does completely different things.

 

I think that soundpost placement and tension effects the leverage that the bridge has against the bassbar.  If you think of the mass of the bar similar to the weight of the head of a hammer, and the placement of the soundpost as how far you choke up on the handle it may give some illustration of the point.  Not a perfect analogy and their relationship is more complicated, but I think this is one of the ways in which they effect eachother.  Typical specs would put the center of both ankles on the center of the soundpost and bar and you can imagine that the way bar mass vs soundpost tension may have a similar effect on the bridge torsion even though the bar and post serve different purposes.  Of course that is just one component of the interaction, and it's hard to really evaluate the change before and after a bassbar change.  Especially if one has a preconceived notion of what to expect.

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There really is no consensus at all on the effect of soundpost placement (various detailed scientific studies measure conflicting results), and that's something it's a hell of a lot easier to experiment with than bassbar placement!

I think it's probably very easy to hear what you expect to hear ...

However, it's very easy to experiment to a limited degree with bridge placement. I've really never come across a situation where the sound is affected adversely by having the left bridge foot sit directly over the bassbar.

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If I were to try my hand at a bassbar placement experiment I would run a Chladni frequency vibration analysis to mark the node areas with exsisting bar.  Maybe run the test again without the bar and then run the test with a newly shaped bar located differently a few mm's placement wise.  Then check node areas again to see if anything moved, decreased or expanded in size.  I would have to be absolutely bored to do this, though.

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How do you run a truly controlled experiment on bass bar adjustments?

 

That is, how are the changes done without affecting anything else that in turn can affect the tone?

 

Who decides that the change is an improvement?

 

This looks like a sem-rhetorical question, with the answer being that you really can't be sure of anything, once you try to move a bass bar around.  You'd always have the potential perturbations of taking off and re-gluing a top, and associated uncertainties of getting the soundpost exactly in the same spot, in addition to the uncertainties of how you measure the results.

 

As to whether it's an "improvement", I think it depends...

 

Say for the sake of argument that you CAN show precisely what changes are produced by moving the bass bar around, and that these changes are consistent from one instrument to another (probably impossible, but just sayin...).  Now, whether a change is good or bad will depend on what you are starting with.  More bottom end would be good for a stiff, harsh instrument, but bad for a tubby one.  And, of course, you might not just get one change, but a basket full of changes throughout the spectrum, and how that meshes with the starting condition becomes less obvious.

 

Fortunately, I don't think the bass bar positioning does much, so I don't worry about about it and just make sure it's mostly under the foot of the bridge. 

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Can anyone articulate their impressions of the effect of bassbar placement on sound?  I am trying to weigh the balance between my training and the oddly proportioned instruments that I often see.

 

What do you believe is the tonal effect of moving a bassbar further in, further out, or angled in some way other than the 1/7 proportion?  Also, mass and stiffness variations for that matter.

 

I had a stock of bridges in 1mm increments from 40mm - 44mm to try and keep the bridge centered while maintaining the proper overlap over the bassbar and came to the conclusion that a poorly placed bassbar should not necessarily dictate bridge width.  In theory a bar further out should get the wider bridge, but I have not found it to necessarily be the right choice.  I have also had better luck with bridges centered on the f-holes/centerline rather than shifting them off center to match the bassbar overlap.  

 

I imagine that the effect of mass of the bar is similar to effect of tightness of the sound post, and effect of moving the bar inward or outward is similar to moving the post inward or outward.  I can't say that I have documented enough bassbar details to have a clear picture of how an oddly placed bar effects sound.  

 

I think that understanding the effects of changes to the bassbar might better inform placement of a new bassbar that might be more specific to the instrument.  For example, a wider bar to add a little more mass to help get a stiff top moving?

 

The closest similar topic that I found was about 43mm and 44mm bridge placements.  A couple interesting points in there, but not quite what I'm looking for.

 

http://www.maestronet.com/forum/index.php?/topic/326383-43-and-44-mm-bridge-blanks-for-violin

 

As always, thanks for the feedback.

Why is it called a bassbar in the first place?  A reason is because it's underneath the bass side strings running along the length of the plate.  The more the angle of such said bar could enable it to be called a tone bar of sorts.  Make and glue a piece of wood 90 degrees to the grain of the wood then we do have a tone bar- more so if it's under the bridge feet.  You take wood from it and the tone will change.  Now, running lengthwise with the grain, like a bassbar in a violin is supposed to, I find you can't change tone very much.

 

  David Lashof explained over at ALL-Experts the proper way to work a bassbar into your build.  I believe I used Curtin's method of thicknessing a bar while glued to the plate.  Do include the belly thickness with your bassbar thickness for the most part.  I don't see or really thought about how a greater mass bassbar could move a stiff top.  Seems to me it would just add weight but on a wide grained top that may be something to try.

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There really is no consensus at all on the effect of soundpost placement (various detailed scientific studies measure conflicting results), and that's something it's a hell of a lot easier to experiment with than bassbar placement!

I think it's probably very easy to hear what you expect to hear ...

However, it's very easy to experiment to a limited degree with bridge placement. I've really never come across a situation where the sound is affected adversely by having the left bridge foot sit directly over the bassbar.

 

Fair point.  

I'd be interested to see the studies on soundpost placement(even though results conflict).  I don't recall having come across it.  

 

My goal in seeking other feedback is largely to challenge my own perceptions, which are not based on any scientific or controlled experiments.  I was thinking that by gathering the observations of others there may be at least some portion of a trend.  DGV's observation about the tonal change is helpful.  It may be unscientific and ambiguous (as most tonal changes), but if many reports show results that are at least partially similar, then perhaps it's something to look at more closely. I think of post adjustments as striking a balance between attributes inherent to the instrument, and the bar may be similar in that respect.

 

Don pointed out that the changes are subtle.  I think most of the changes on the instrument are subtle, which is why we struggle to identify the effect of any individual component.  Interesting to hear from someone who has done experimentation and found nothing conclusive.

 

How do you run a truly controlled experiment on bass bar adjustments?

 

That is, how are the changes done without affecting anything else that in turn can affect the tone?

 

Who decides that the change is an improvement?

 

I have begun dabbling with a method of testing instruments that allows me to do a comparison before and after an adjustment.  I will take 3 - 5 instruments and conduct a play test with at least 2 observers (including the player) who will rate various attributes and make any additional notes about details that stand out.  Then I will change one instrument and do the same test with the same player and observers.  Their ratings of the same instrument are not identical from one trial to the next, but the trends are similar.  It also gives some sort of comparative metric to assess the change.  This allows a small level of consistency when comparing after a day or two while to work is being done.  I have also considered it as a way to assess a new string as it breaks in.  I have struggled with terminology in identifying what attributes to rate, and how to describe them.  Even so, with tests done within a relatively short period of time it seems to help organize one's idea of what is being heard.  In that respect it isn't really about the ratings at all.

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I just finished moving a bassbar on an inexpensive factory violin. I soaked the joint so I could remove the bar intact and refit it in the proper location with minimal other changes. The bar had been 3.5mm inside a 42mm bridge foot with the bridge centered. I tried setting it up with an off-center bridge with a 1mm bar overlap, but that was not great either

 

 

I, too have  been faced with this dilemma on where to position a bridge for an ill-placed bar, and wondered about the tonal effects of off-centered bridges.  One variable I keep in mind is the nut - bridge - end pin alignment.  The off-centered bridge may have resulted in poor tone because of the "dogleg"  created in the string path.  My experience is that the tone gets muffled when the strings don't travel a straight line from nut - bridge - end pin.

 

By the way, thanks for bringing up this topic. I can put them in but have a long way to go in understanding the effects of the variables in placement and shape.

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Most makers and repair men put the bassbar 1.5 mm inside the bridge foot. Surely they can't be wrong.

My own experience is that the bassbar helps the lower frequencies, especially on the G. Apart from that if the bridge foot is not over the bar, there maybe some irregular movement in transferring the sound from the bridge to the belly. I'm sure observing the movements of the bridge foot in slow motion would confirm this.

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Most makers and repair men put the bassbar 1.5 mm inside the bridge foot. Surely they can't be wrong.

 

Probably if it was wrong, they wouldn't do it; so in that sense, you'd be correct in saying it can't be wrong.  But that doesn't mean that a millimeter or so either way would make any difference... i.e. nearly everything would be equally right.

 

My own experience is that the bassbar helps the lower frequencies, especially on the G.

 

 

I "helped" the lower frequencies by removing the bass bar entirely:

post-25192-0-49520500-1431639908_thumb.jpg

 

The fundamentals below the A string were all stronger.  Not good, for many reasons, but that's what happened.

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Most makers and repair men put the bassbar 1.5 mm inside the bridge foot. Surely they can't be wrong.

My own experience is that the bassbar helps the lower frequencies, especially on the G. Apart from that if the bridge foot is not over the bar, there maybe some irregular movement in transferring the sound from the bridge to the belly. I'm sure observing the movements of the bridge foot in slow motion would confirm this.

Not on this side of the ocean. I was taught to use 1 mm inside and recently have heard that colleagues are using slightly less. I beleive R. Hargrave recently said on an MN thread that he uses 1/2.

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 Either hardly anything happens, or whatever happens is somewhat random and hard to pin down.

 

 

I have the same feeling. I tried to put bassbars on few integrated junk violins. I found it hardly change the tone characteristic.

The only dramatic change is the volume due to higher tension allowed. The shape and thickness of the bar is a puzzle to me.

 

I have read that master maker in the old days can tap the bar and tune it but I am not sure what to tune.

 

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Not on this side of the ocean. I was taught to use 1 mm inside and recently have heard that colleagues are using slightly less. I beleive R. Hargrave recently said on an MN thread that he uses 1/2.

 

My put is the sweet spot may be different depend on the stiffness distribution of the top. 1mm inside is a empirical rule because we can't move a bassbar like a sound post. Imagine if the sound post has to be fixed. How would you teach your student? I will say something like "3mm behind the foot..."

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I have read that master maker in the old days can tap the bar and tune it but I am not sure what to tune.

 

 

You can find all kinds of things written.  After you filter out (if possible) the things that are not true, and then further filter out the things that are true but unimportant, you probably won't have much left.

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