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Thread: New Builders Tap tuning

  1. #1

    Default New Builders Tap tuning

    Ok, letís tackle tap tuning. I tapped my little self silly with istrobesoft, clamp on tuners and several others, and I cannot hear or replicate what Siminoff says. First I neither hear nor measure any difference in the tone bars. I can eventually get a consensus note for a plat or rim assembly, but with two kits and two from scratch, Iím stumped. I read on here some long time builders trashing tap and others think itís gospel. The label inside Loarís say something like ď parts were tunedĒ whatever that meant to them. I donít think he had iStrobesoft. The two from scratch so pretty good, but that may be a parent talking. Help

  2. #2
    Registered User fscotte's Avatar
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    Default Re: New Builders Tap tuning

    I think if you can be 100% consistent in each top plate you build, then it may work. That means consistent in arch size, shape, mass distribution, stiffness distribution, tone bar weight and size and placement, etc..

    Even with a cnc machine, this is still difficult, because wood is not 100% consistent it it's stiffness and mass.

    Here's an experiement anyone can do. Take a 5 gram piece of clay and place it near the center of the top of a mandolin. Just 5 grams will lower the tap note of your mando. You can check the tap note with an fft program such as Audacity for computer, or any other fft app on a smartphone.

    If the 5 gram weight is placed near the edge, it has nearly no affect on the tap note. So it's a question of weight distribution. If just 5 grams can lower the tap note, how do you control weight distribution when carving from one plate to the next?

    F'nstance, if carving two plates, how can I be sure that the center of each plate are of equal weight? The amount of mass near the center will affect the tap note more than if the mass is nearer the edge

    And that's just for mass. Stiffness works the same way. The more the stiffness near the center, the more it affects the tap note.

    So it's extremely difficult to be consistent. And I think people like Siminoff and others have found that to be true. Siminoff has a very wide range for his tap note targets, I've seen him suggest Gb to C. Now that's a very wide margin..

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    Default Re: New Builders Tap tuning

    I used to do this, and try for the target note, on occasion , I could achieve it,but on occasion,. I would tap the note, and never get the target note, right to the point of shaving the bar out, and starting over, so, I finally got to where I would tap it to the closest note , and call it good, for instance if I had C +45 cts. I took it to C and left it. A member here helped me, and told me he thought deflection tuning was more valid then tuning the bars. tuning the plate,, always a war on this topic. My buddy a builder told me , instead of tap tuning, I should go in the yard at midnight the first full moon and throw chicken bones on the ground and dance around it, I disagreed , but there it is, good luck
    Mike Marrs

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    Default Re: New Builders Tap tuning

    I think time spent getting the proper shape of the plates is a better use of time along with proper thicknessing. Tapping won't help if you have a trench instead of a graceful recurve or a back that is too stiff.

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    Default Re: New Builders Tap tuning

    Iím in the camp that says tap tuning (as described by Siminoff, that is, tuning parts to specific notes) is utterly useless. Achieving a particular note only means you got that piece of wood to a certain mass. You could find the same note on a flat piece of wood if you thicknessed it to the proper dimension. Think marimba bars.

    This doesnít mean I donít tap or scratch the tops and backs while I carve and flex them but Iím looking for a particular type of sound and flexibility that is unfortunately, totally subjective and I couldnít describe it if I tried! Plus, I know what is in or out of the ballpark for graduations in the instruments I build and all these things together inform my decisions about how much wood to remove.

    And one more thing, as Jim pointed out , unless each top and back you carve have exactly the same recurve and arching, you wonít learn anything useful from comparing one build to the next. Those two things are your foundation. Everything else builds from there.

    Incidentally, my braces are always the same size. 😉

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  10. #6
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    Default Re: New Builders Tap tuning

    I’m in the camp that says tap tuning (as described by Siminoff, that is, tuning parts to specific notes) is utterly useless
    Agreed. Personally I think Siminoff's chapter on tap tuning should be torn out and burned. Relative tuning of the top and back is another story.
    Peter Coombe - mandolins, mandolas and guitars
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  12. #7

    Default Re: New Builders Tap tuning

    Quote Originally Posted by fscotte View Post
    I think if you can be 100% consistent in each top plate you build, then it may work. That means consistent in arch size, shape, mass distribution, stiffness distribution, tone bar weight and size and placement, etc..

    Even with a cnc machine, this is still difficult, because wood is not 100% consistent it it's stiffness and mass.

    Here's an experiement anyone can do. Take a 5 gram piece of clay and place it near the center of the top of a mandolin. Just 5 grams will lower the tap note of your mando. You can check the tap note with an fft program such as Audacity for computer, or any other fft app on a smartphone.

    If the 5 gram weight is placed near the edge, it has nearly no affect on the tap note. So it's a question of weight distribution. If just 5 grams can lower the tap note, how do you control weight distribution when carving from one plate to the next?

    F'nstance, if carving two plates, how can I be sure that the center of each plate are of equal weight? The amount of mass near the center will affect the tap note more than if the mass is nearer the edge

    And that's just for mass. Stiffness works the same way. The more the stiffness near the center, the more it affects the tap note.

    So it's extremely difficult to be consistent. And I think people like Siminoff and others have found that to be true. Siminoff has a very wide range for his tap note targets, I've seen him suggest Gb to C. Now that's a very wide margin..
    Thanks for that. What you’re telling me is more experience helps. Yeah Siminoff has different notes in different books. Of course the goal is to predict a good sound from the parts before you put it together. I’m still frustrated in understanding any kind of results from tap tuning. Other builders give different notes. Thanks for answering.

  13. #8

    Default Re: New Builders Tap tuning

    Quote Originally Posted by Martian View Post
    I used to do this, and try for the target note, on occasion , I could achieve it,but on occasion,. I would tap the note, and never get the target note, right to the point of shaving the bar out, and starting over, so, I finally got to where I would tap it to the closest note , and call it good, for instance if I had C +45 cts. I took it to C and left it. A member here helped me, and told me he thought deflection tuning was more valid then tuning the bars. tuning the plate,, always a war on this topic. My buddy a builder told me , instead of tap tuning, I should go in the yard at midnight the first full moon and throw chicken bones on the ground and dance around it, I disagreed , but there it is, good luck
    Iíll try the chicken bones 😊

  14. #9

    Default Re: New Builders Tap tuning

    Quote Originally Posted by peter.coombe View Post
    Agreed. Personally I think Siminoff's chapter on tap tuning should be torn out and burned. Relative tuning of the top and back is another story.
    Relative tuning? One note apart?

  15. #10

    Default Re: New Builders Tap tuning

    Quote Originally Posted by Jim Hilburn View Post
    I think time spent getting the proper shape of the plates is a better use of time along with proper thicknessing. Tapping won't help if you have a trench instead of a graceful recurve or a back that is too stiff.
    Yes I try to go by the Siminoff dimemsions and templates.

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    Default Re: New Builders Tap tuning

    I only have Sim's original book from the 70's and don't know how he's changed things since then but I'd highly recommend Adrian Minirov's plans which I believe are available at Elderly.

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    Default Re: New Builders Tap tuning

    Larry my experience is limited but Iíll share my findings thus far. Iíve got both Siminoff books and he says to tune the bass tone bar to Ab and Treble bar to A#. I was always confused and could never achieve that. Mr. Dearstone says he tunes the top (along with the tone bars) to a C and back to D...Mr GilChrist tunes to a specific note also. Iíve emailed him and have asked to what notes he tunes but received no reply. On my #6&7th Mandolin, I tuned the top assembly to a C note(without the neck attached) simultaneously carving the tone bars down and tuning it as an ASSEMBLY not each tone bar separately. These Mandolins turned out with a great sound. A friend(who also builds) was impressed and decided to take the back off his stewmac kit. We couldnít achieve a C note on his top because the neck was attached. We wound up tuning his whole assembly to A440 believe it or not and the back to a D# note(because he didnít want to take no more wood off as I begged him to lol). That mandolin turned out to be a canon. Go figure? Iím thinking that what other builders is saying about proper arching, graduations etc or absolutely important. But I also believe that tuning The assemblies are important as well. Iím currently building #8 and tuned with the neck attached to A441(leaving a little for final sanding) and the back is closer to a 261hrtz because when I reached graduation points it was already past my D target. Instead of discarding a perfectly fine piece of fiddle back maple, I went ahead and attached the back. It could turn out as a dud who knows? But the resonant frequency of the air chamber measures exactly a D 293-4hrtz. which in my understanding will climb somewhat when the pressure of the strings are applied.
    I said all that to say this, at this point Iím gambling BUT I hope to get to a persistent method of building using a combination of all techniques. Correct grads, archings, recurves, AND tunings etc. Itíll take many more builds to get to that point and perhaps Iíll never reach it. All I know is that itís fun learning with each one and I wish I had the time to do more....

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    Default Re: New Builders Tap tuning

    I am a relative newbie to this but, tapping to try and achieve a specific pitch is BS. I bought all of Siminoff's stuff and spent a lot of money on testing equipment. Carved the bass bar all the way off. BS. I feel it is much better to carve to ur numbers and voice it when you are done. Taught this by a very good builder. I do think the size of your tonebars has a huge effect on what u r trying to achieve.

  20. #14

    Default Re: New Builders Tap tuning

    For someone who has not observed the process from someone first hand, what the heck would I know what I was listening for exactly? Not that I didn't rap my knuckles against the back and top a bunch when building my Arches kit. What I did do, in the desire for a bright tone to complement my Silverangel, was go very conservative with carving the plates and braces. To that goal I succeeded, and wonder of wonders, it hasn't folded up.
    Silverangel A
    Michael Kelly LSFTB
    Arches F style kit

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  22. #15

    Default Re: New Builders Tap tuning

    I tap a lot on vintage instruments, as well.................it's called "checking for loose braces!"

    But, in all seriousness, I WANT to believe in tap tuning -- that is -- the belief that an experienced builder can hear things "we" can't hear and make fine adjustments and tuning, based on arcane knowledge........

    I will repeat the story I heard about John D'Angelico, FWIW........when a potential client went to discuss the possibility of him building a custom guitar, supposedly D'Angelico would hold both of your hands in his for an uncomfortably long amount of time, then finally let go and say something like "OK, I builda u nice guitar!"

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    Default Re: New Builders Tap tuning

    https://www.mandolincafe.com/forum/s...g-F5-mandolins

    There’s a lot of threads on this subject. This one for example that I’ve saved. Let us know what camp ya join brother....Either the “ This is Hogwash and BS” camp OR “ There must be something to this or reputable builders wouldn’t be using this technique to produce awesome mandolins that the world covets” camp...
    Last edited by Clinton Johnson; Aug-12-2018 at 4:59pm.

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  26. #17
    Registered User fscotte's Avatar
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    Default Re: New Builders Tap tuning

    Well, the proof that it doesn't work is because if it did, them everybody would be building stellar sounding mandos. It's very simple and easy to get a plate to a certain note.

    What I've gathered from experienced builders here, is that what's more important is the relationship between the plates and how they interact with the internal air resonance.

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    Default Re: New Builders Tap tuning

    Agreed Fscotte, and the way you achieve good relationship between plates is by deflection tuning, correct? Would it be reasonable to say that tap tuning could achieve the same goal when one learns how to make it work for him?

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    Default Re: New Builders Tap tuning

    I'm in the hogwash category as to a specific note. And I have always given a world of credit to Siminoff for his first book. It probably started a lot of us back in the day. But how one can tune one tone bar to a note and the other one to a different note when they're both glued onto the top plate is a mystery to me. Heck, you can tap on different parts of the plate and get different notes depending on where you're holding the plate. But you do figure out where to hold it to get what you need. I do know what I want to hear and I know when I hear it. And then I stop carving and messing with it. Both top and back, and then back and forth between one and the other- a relationship. I don't know what notes they are. And that all changes anyway when things are glued to the rim. After a certain number of instruments with the same plate arching and rim height, things become fairly predictable. I don't know what's going to happen when my "hearing" goes away for whatever reason. Probably have to start building electrics.

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    Default Re: New Builders Tap tuning

    I would never say it's hogwash just because I don't understand it even though I've heard some of the big names say just that.
    My point is if you are on your first or so mandolin there are a lot of fundamentals to learn without getting off in the weeds too far.

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  33. #21
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    Default Re: New Builders Tap tuning

    Quote Originally Posted by Clinton Johnson View Post
    Agreed Fscotte, and the way you achieve good relationship between plates is by deflection tuning, correct? Would it be reasonable to say that tap tuning could achieve the same goal when one learns how to make it work for him?
    Deflection tuning might be more reliable but again, you have to carve exactly the same way each and every time. In addition, it's nearly impossible to achieve consistent deflection results for the back plate.

    Unfortunately, you can't just make the back plate deflect to a set number every time. In fact, I don't even use deflection on the back plate. I find it to be useless.

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  35. #22
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    Default Re: New Builders Tap tuning

    Here we go again!

    First of all, you cannot tune individual parts. The whole thing vibrates as a whole. If you are tapping one tonebar you are exciting one mode of vibration, and another mode of vibration when you tap the other tone bar. You can see this clearly if you try Chladni patterns. This applies to free plates, partially assembled, or a finished mandolin with the strings on. Siminoff was correct in that it is useful to get the main modes of vibration of the finished mandolin with strings on between notes (from lots of research done on guitars), but the modes are whole body modes, not just individual parts so he got that bit wrong. Problem is, nobody has shown any relationship between modes of vibration of free plates or a partially assembled instrument to modes of vibration of the completed instrument. Note that the tailpiece and bridge will change the frequencies, so it gets complicated, and relationships are very likely to be non linear. There must be some sort of relationship because if you carve a top or back thicker then the frequencies must be higher in a free plate and also in the assembled instrument. The best we can do is to build a database of measurements and note down the sound, and form empirical conclusions without really knowing what the relationships are - i.e. if I do this then I get a certain sound. I did this with oval hole mandolins and published it -
    http://petercoombe.com/jaamim7.html
    http://petercoombe.com/jaamim8.html

    Problem with archtop instruments is that it is difficult to measure modes of vibration on the completed instrument. The best way is with laser interferometry which is very sensitive to frequency, but does not measure amplitude. Unfortunately you do need a laser interferometer which are not cheap so the average Luthier won't have one. Dave Cohen has published papers on this, but the average Joe will find these papers fairly heavy going, but they do indicate reality and not some hair brained theory. Suffice to say, mandolins are similar to guitars, but the frequencies are higher, and the frequencies vary depending on what type of mandolin it is.

    At the moment I am measuring free plates and completed instrument measurements on my pancake flattop mandolins to try and understand how this stuff works once the mandolin is assembled - i.e. can I predict what will happen from the free plate measurements. I am using my pancake mandolins because they are about as simple as a mandolin can be, yet still be a decent sounding mandolin, and are much easier to measure than arch top mandolins. This is likely to take years before I can make any sense out of it.
    Peter Coombe - mandolins, mandolas and guitars
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  37. #23

    Default Re: New Builders Tap tuning

    Quote Originally Posted by peter.coombe View Post
    Agreed. Personally I think Siminoff's chapter on tap tuning should be torn out and burned. Relative tuning of the top and back is another story.
    With my very limited experience, the relative tuning seems to be valid....

  38. #24

    Default Re: New Builders Tap tuning

    Quote Originally Posted by Jim Hilburn View Post
    I only have Sim's original book from the 70's and don't know how he's changed things since then but I'd highly recommend Adrian Minirov's plans which I believe are available at Elderly.
    Yeah, I'm tempted to buy the plans, but at $85 not yet bit the bullet...

  39. #25

    Default Re: New Builders Tap tuning

    Quote Originally Posted by Clinton Johnson View Post
    Larry my experience is limited but I’ll share my findings thus far. I’ve got both Siminoff books and he says to tune the bass tone bar to Ab and Treble bar to A#. I was always confused and could never achieve that. Mr. Dearstone says he tunes the top (along with the tone bars) to a C and back to D...Mr GilChrist tunes to a specific note also. I’ve emailed him and have asked to what notes he tunes but received no reply. On my #6&7th Mandolin, I tuned the top assembly to a C note(without the neck attached) simultaneously carving the tone bars down and tuning it as an ASSEMBLY not each tone bar separately. These Mandolins turned out with a great sound. A friend(who also builds) was impressed and decided to take the back off his stewmac kit. We couldn’t achieve a C note on his top because the neck was attached. We wound up tuning his whole assembly to A440 believe it or not and the back to a D# note(because he didn’t want to take no more wood off as I begged him to lol). That mandolin turned out to be a canon. Go figure? I’m thinking that what other builders is saying about proper arching, graduations etc or absolutely important. But I also believe that tuning The assemblies are important as well. I’m currently building #8 and tuned with the neck attached to A441(leaving a little for final sanding) and the back is closer to a 261hrtz because when I reached graduation points it was already past my D target. Instead of discarding a perfectly fine piece of fiddle back maple, I went ahead and attached the back. It could turn out as a dud who knows? But the resonant frequency of the air chamber measures exactly a D 293-4hrtz. which in my understanding will climb somewhat when the pressure of the strings are applied.
    I said all that to say this, at this point I’m gambling BUT I hope to get to a persistent method of building using a combination of all techniques. Correct grads, archings, recurves, AND tunings etc. It’ll take many more builds to get to that point and perhaps I’ll never reach it. All I know is that it’s fun learning with each one and I wish I had the time to do more....
    thanks, this kinda parallels my experience so far...

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