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Thread: Hi total newb here...

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    Default Hi total newb here...

    I did do a prelim search in order to answer my question, which is: Is there some formula for establishing where the sound/tone bars go in relation to any other established landmark on the instrument? An example: (From Siminoff's Book) Offsetting them in relation to the center line.

    His reasoning for that particular instrument seemed reasonable but what about on a "hybrid" (and I do hate that terminology) piece? -Harry

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    Registered User sunburst's Avatar
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    Default Re: Hi total newb here...

    I once heard Don McCrostie say that he had tried placing the tone bars in different positions left to right and heard no particular difference. I breathed a sigh of relief and went on to experiment with other aspects of construction happy that tone bar placement was not something I needed to be too concerned with.

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    Default Re: Hi total newb here...

    Quote Originally Posted by sunburst View Post
    ... and went on to experiment with other aspects of construction happy that tone bar placement was not something I needed to be too concerned with.
    Hi John. So, what were some of the (tone bar) issues you were considering up until that time?

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    Registered User sunburst's Avatar
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    Default Re: Hi total newb here...

    Just thought about moving them side to side, maybe close together, maybe farther apart, see if there was any sound difference. I like it when somebody else tries things and reports that "nothing happens"; then I don't have to try the experiment myself!

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    Certified! Bernie Daniel's Avatar
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    Default Re: Hi total newb here...

    Quote Originally Posted by sunburst View Post
    Just thought about moving them side to side, maybe close together, maybe farther apart, see if there was any sound difference. I like it when somebody else tries things and reports that "nothing happens"; then I don't have to try the experiment myself!
    Given the fact that are those who claim -- with no small amount of certainty either, that varnish (instead of lacquer), or hide glue (instead of lacquer), or one kind of spruce versus another, or a total contact bridge versus a "two-foot" bridge all make a difference (a big difference?) in the sound of a mandolin -- it is indeed good to find that tone bars don't matter!

    Oh but then don't I recall that one way to supercharge a mandolin is to scallop the tone bars!
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  7. #6

    Default Re: Hi total newb here...

    How could the position of the bars not matter? It must IMO as vibrations will be conducted differently throughout the body when they are in different locations. Why even have them if it doesnt matter where they are and why did Loar design his to be so close to the f holes on the bass bout? Cuz it matters I'm a thinkin'.

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    Default Re: Hi total newb here...

    Quote Originally Posted by shortymack View Post
    How could the position of the bars not matter? It must IMO as vibrations will be conducted differently throughout the body when they are in different locations. Why even have them if it doesnt matter where they are and why did Loar design his to be so close to the f holes on the bass bout? Cuz it matters I'm a thinkin'.
    There are too many variables to make a statement like that. I think some of the terms we're using in this thread are misleading.

    The placement of the bars does "matter". However, when the above posters are saying it "does not matter", they mean that when properly tuned and adjusted, the tone bars in Instrument A will perform a very similar function to the tone bars in Instrument B.

    Is the spruce exactly the same strength from centimeter to centimeter across its width? Across its length? Of course not. But these are things we learn to deal with, the position of the bars themselves as just one of many variables.

    According to Siminoff, the reason for the placement of tone bars in Loars is that they made it easier to reach the desired tap tones, whatever the basis was. But the "incorrect" placement of the bars does not preclude the proper tuning of the plate... of course every luthier's definition of the "proper tuning" will be different, but that's the gist. Cohen uses his weird bracing scheme because he likes it. It's probably that simple in the case of the Loar tone bars too, if I could hazard a guess.

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    Default Re: Hi total newb here...

    Quote Originally Posted by shortymack View Post
    How could the position of the bars not matter? It must IMO as vibrations will be conducted differently throughout the body when they are in different locations. Why even have them if it doesnt matter where they are and why did Loar design his to be so close to the f holes on the bass bout? Cuz it matters I'm a thinkin'.
    I'm thinking too. The mass-producers had to have enough time and money to stir things around under the hood in order to gain some edge in the market. And sure, those models are going to get copied at some point, e.g., the ubiquitous F5 design knock offs and the pre-war Martin copies. Other than the sound (important) quality which we all seek, what insights do others have in regard to their OWN designs? Does someone believe that no less than 47 tone bars is Nirvana for the eardrums? (Apparently, whoever makes "The Loar" now believes that 0 bars are fine as they have 2 models without any. )

    I suppose it's those models that never made it to the production line are the ones which are valuable because they showed what NOT to do and the everyday chump like me will never get to see one.

    So, essentially, I'm getting either that A: The tone-bar placement (if someone has decided to put them in at all) is not too much of an issue and that B: Gibson did it a certain way for a reason.

    Theoretically though, if you were presented with a design we'll call "x" AND if you decided that you wanted tone bars, what parameters would you define for yourself in determining where to put them?

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    Default Re: Hi total newb here...

    Quote Originally Posted by ArtDecoMandos View Post
    However, when the above posters are saying it "does not matter", they mean that when properly tuned and adjusted, the tone bars in Instrument A will perform a very similar function to the tone bars in Instrument B.
    i thought that might be what 'sunburst' meant but I did feel the sting of disappointment. Cohen has made some decent sounding doe's I take it.

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    Registered User sunburst's Avatar
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    Default Re: Hi total newb here...

    FWIW, I don't tune plates or tone bars to specific notes, there is no need. (It works in some people's building systems.)
    Tone bars, assuming we're talking about two bars running roughly lengthwise the grain of a top with two holes to each side (typical "F-5" "A-5" construction), add stiffness to the top lengthwise without adding stiffness crosswise. If the goal is to stiffen the top longitudinally while not stiffening it laterally, the exact placement of the bars is not important. What is important is getting the top to have the correct stiffness (longitudinally and laterally) and mass to work well for the builder's system of building.

  12. #11

    Default Re: Hi total newb here...

    Quote Originally Posted by ArtDecoMandos View Post
    There are too many variables to make a statement like that. I think some of the terms we're using in this thread are misleading.

    The placement of the bars does "matter". However, when the above posters are saying it "does not matter", they mean that when properly tuned and adjusted, the tone bars in Instrument A will perform a very similar function to the tone bars in Instrument B.

    Is the spruce exactly the same strength from centimeter to centimeter across its width? Across its length? Of course not. But these are things we learn to deal with, the position of the bars themselves as just one of many variables.

    According to Siminoff, the reason for the placement of tone bars in Loars is that they made it easier to reach the desired tap tones, whatever the basis was. But the "incorrect" placement of the bars does not preclude the proper tuning of the plate... of course every luthier's definition of the "proper tuning" will be different, but that's the gist. Cohen uses his weird bracing scheme because he likes it. It's probably that simple in the case of the Loar tone bars too, if I could hazard a guess.
    The posts say that placement did not matter, not how refined or tuned the bars were. Thats what I was basing my statement on is all. Guess Im wrong, but why are they called 'tone bars' then and not just braces?

  13. #12

    Default Re: Hi total newb here...

    Quote Originally Posted by shortymack View Post
    Guess Im wrong, but why are they called 'tone bars' then and not just braces?
    Braces are for structure. Tone bars are for adjusting the acoustic properties of the plates. They add structure, and that's how they work, but that is not their reason for being.

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    Registered User Bill Snyder's Avatar
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    Default Re: Hi total newb here...

    Shortymack, John (sunburst) said "If the goal is to stiffen the top longitudinally while not stiffening it laterally, the exact placement of the bars is not important".
    That stiffening DOES affect tone, so they are tone bars.
    Bill Snyder

  15. #14

    Default Re: Hi total newb here...

    Quote Originally Posted by sunburst View Post
    FWIW, I don't tune plates or tone bars to specific notes, there is no need. (It works in some people's building systems.)
    John, but you do tune plates to something, which is all I was trying to say. It might not be a reading on a strobe tuner, but it is some kind of amalgamation of your experience that you are listening for or generally carving towards. For me it's much more about holding it in my hands and flexing it different ways to see what it feels like.. the tap tuning I do is more just another frame of reference.

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    Default Re: Hi total newb here...

    Quote Originally Posted by Bernie Daniel View Post
    Given the fact that are those who claim -- with no small amount of certainty either, that varnish (instead of lacquer), or hide glue (instead of lacquer), or one kind of spruce versus another, or a total contact bridge versus a "two-foot" bridge all make a difference (a big difference?) in the sound of a mandolin -- it is indeed good to find that tone bars don't matter!

    Oh but then don't I recall that one way to supercharge a mandolin is to scallop the tone bars!
    Thanks Bernie. It's a jungle out there. I imagine we'll all share a vine or two now and then.

  17. #16

    Default Re: Hi total newb here...

    Quote Originally Posted by Bill Snyder View Post
    Shortymack, John (sunburst) said "If the goal is to stiffen the top longitudinally while not stiffening it laterally, the exact placement of the bars is not important".
    That stiffening DOES affect tone, so they are tone bars.
    Ok, I understand but.... kerfing (for example) has an effect on strengthening the body which in turn acts as a platform to stiffening the top as well but it isnt called tone kerfing. Why would you shape or scallop the bars if they were just for structural purposes?


    Please dont get me wrong Im not trying to be a smart _ _ _ and enjoy the disscussion. Nor am I a builder but just cant help to think that placement along with shape and everything else does matter as far as tone goes. It all matters.


    Ok, Ill shut up now.

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    Default Re: Hi total newb here...

    Quote Originally Posted by sunburst View Post
    FWIW, If the goal is to stiffen the top longitudinally while not stiffening it laterally, the exact placement of the bars is not important. What is important is getting the top to have the correct stiffness (longitudinally and laterally) and mass to work well for the builder's system of building.
    It's worth a great deal to me thanks. So, I might look at the grain and determine that it would benefit from some support. A tighter grain needing less and a wider grain more. Perhaps? Why not during the carving process, just leave the area that would be covered by the tone bars more or less thick?

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    Default Re: Hi total newb here...

    Quote Originally Posted by shortymack View Post
    Ok, I understand but.... kerfing (for example) has an effect on strengthening the body which in turn acts as a platform to stiffening the top as well...


    Ok, Ill shut up now.
    I know this much. That top has to be stiff enough not to split yet vibrate as well. Kerfing... a necessary evil, albeit around the edges of the soundboard. And hey, it's my thread so hang as long as you want to.

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    Default Re: Hi total newb here...

    During my first few builds, I placed the tone bars it the direction that Siminoff suggested in the plans. Later I decided to try them opposite to see what happened. I could not detect a difference at all. I then tried them so that they lay symetrical to each other, and again there was no difference. Later I tried tap tunning and while I want to say that I believe that there may be merit in tap tunning, I did not find a difference in the plates that I tap tuned. There was too much variablility in the process. If the temperature or humidity in the shop changed, there was too was a change in the tap tone of the piece I was tapping to on my Peterson strobe tuner. Also where I held it during the tap tunning process would greatly change the tap note. Then there was the fact that no two tops or backs had the same mass as they were hand carved. To throw another twist in the mix, I had a top that tapped like a dead piece of wood. No matter what I did to it it did not "ring" like my previous builds. I proceeded with the build anyway and made sure it flexed the way I liked it to when it was glued to the rim and it ended up being my best sounding mandolin to date. I think what it boils down to is that you have to work with whatever scenario plays out with the building of the box. If you are happy with the flex of the top plate and the way it responds with the back as a whole unit, it will be a good mandolin. There are a lot of guys who put a lot of science behind the whole process talking about the way plates respond and the function of tone bars or braces, and when I try to read and understand what is being said, my eyes kind of glass over and realize that I have no idea what they are talking about. Just build it and mess with it until it sounds the way you want it to.

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    Default Re: Hi total newb here...

    The stiffness of the wood, the density of the wood, the arch of the top, the graduations of the top, and the bracing of the top all work together for the top to work as it does. (Internal damping is important too, but we don't need to get too involved in this discussion, and besides, we have little control over damping, other than choosing the wood.) "Tone bars" are one means of controlling stiffness and mass of the top, along with arching and graduation.
    Why are they called "tone bars"? Good question. Apparently someone sometime thought it sounded better, or would sell more instruments, if the two longitudinal braces (yes, they are braces) were called "tone bars". Regardless of what they are called; braces, tone bars, whatever (a rose by any other name...), what they do is stiffen the top plate longitudinally and conveniently provide a relatively easy way for the builder to adjust the longitudinal stiffness of the top plate.

    When we learn the basics of plate modes and how top and back plates behave when the instrument is making music it becomes easier to understand what the various components do, but it doesn't get easier to understand why some things are called what they are.

    As for my own building, I work more by stiffness and mass than any other "tuning" of my plates. I adjust the arch height a little according to how the wood feels in terms of stiffness and density, I graduate a little thicker or thinner, also according to how I read the piece of wood, and I weigh my tops and backs. I don't worry about grain count or other visual aspects, they don't have much to do with density and stiffness. I've almost completely quit tapping and listening, though I do listen to the sound of the wood as it is handled and carved. I started out trying to tune to notes, but most of the time I wasn't able to "hit" the notes I was trying for, so I just started recording the notes I got looking for consistencies. Eventually I gave that up too. The sound of my mandolins has gotten more consistent as I've gained experience and quit "tuning". When I have a top carved and braced and ready to glue to the rim I weigh it, and the weight is almost always consistent within about 6 grams. My F-5 tops weigh a few grams over 100 grams, so that means I'm getting weights consistent within 6% or so regardless of spruce species or source. How do I do that? I'm not sure. Also, if I tap my two braces (tone bars, if you prefer ) after gluing the top to the rim they ring notes about a half step apart pretty consistently, but the notes themselves show no particular consistency at all. As I've said before, I see no reason to tune to specific notes because I don't see that it does any good, at least in my building system.
    Eventually I want to do some more precise stiffness measurements ("deflection tuning") in order to have more predictability when using unusual woods, but I don't think I'll ever find a use for tuning parts to specific notes.

    One more thing;
    I just started carving a top from some very light (low density) European spruce. It is less dense than any spruce I can remember using. I'm curious to see what the weight of this top is after carving, and how it compares to other top weights I've recorded. I expect it to be lighter, but I don't know how much. I also don't know what my final thicknesses will be, but I expect it to be a little thicker than my usual red spruce tops. (so much to learn....!!!!)
    Last edited by sunburst; Aug-24-2012 at 10:25pm.

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    Default Re: Hi total newb here...

    Quote Originally Posted by Max Girouard View Post
    Just build it and mess with it until it sounds the way you want it to.
    I got two gifts Max. One on the left side of my head and the other on the right. Thanks. I just might do that.

  24. #22

    Default Re: Hi total newb here...

    Good post, John (and everyone).
    It's important to realize that "tap tuning", in the Siminoff sense, is a production technique. I think a lot of people (including myself) have been lured by the idea that since sound involves science, that achieving some property (tap tone) of some parts is all you need to do to get a Loar.
    It is not intended to be the only way to get good tone, it is intended to be a tool for duplicating the physical properties of an existing, known good, instrument. If you haven't gotten there to begin with, then there is nothing to duplicate.
    Deflection tuning is for the same purpose. But since every builder's materials and specs vary enough to throw it off, there is no magic formula.
    As Darryl Scott said, "there ain't no easy way".

  25. #23

    Default Re: Hi total newb here...

    Oh, and one more thing. We get so worked up about bracing patterns, which finish to use, etc.

    And in reality, most builder's first builds are far more plagued by a bad setup than anything else. Setting up an instrument isn't obvious, easy or quick (at least, when you're getting started.) It has taken me 10 years to feel like I really know what to do to get a good setup. There's a lot more productive things to focus on than the resonant frequency of your second instrument's bass tone bar.

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    Default Re: Hi total newb here...

    "Cohen uses his weird bracing scheme because he likes it......"

    That's not quite correct, and I have addressed that in other threads. I originally used it because I thought there might be something to it. By the time I got around to doing enough physics on the subject myself and realizing that there wasn't anything to it, I had gotten used to working with it. That's not the same thing as 'liking it', more like fait accompli. I have stated several times on this forum that the pattern works fine, but is no better than any other pattern.

    I have used the term 'wacky braces' for my bracing pattern in an attempt at self-deprecating humor. Still, there is a bit of sting associated with hearing or seeing someone else refer to my bracing pattern as 'weird'. I make it a point to not refer to other luthiers in threads which they haven't weighed in unless I am referring to them in a positive light.

    http://www.Cohenmando.com

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    Default Re: Hi total newb here...

    Quote Originally Posted by sunburst View Post
    When I have a top carved and braced and ready to glue to the rim I weigh it, and the weight is almost always consistent within about 6 grams. My F-5 tops weigh a few grams over 100 grams, so that means I'm getting weights consistent within 6% or so regardless of spruce species or source.
    Is humidity a variable or pretty much constant?

    I just started carving a top from some very light (low density) European spruce. It is less dense than any spruce I can remember using. I'm curious to see what the weight of this top is after carving, and how it compares to other top weights I've recorded. I expect it to be lighter, but I don't know how much. I also don't know what my final thicknesses will be, but I expect it to be a little thicker than my usual red spruce tops.
    Why wouldn't you shoot for a similar weight on this piece instead of mass or thickness? Does it not follow that "more" sound freqs could be absorbed by a piece of similar weight having more mass? I'd like to know if the flexibility is there at a given weight.

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