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Thread: how to get perfect compensation, tool perhaps?

  1. #1

    Default how to get perfect compensation, tool perhaps?

    Is there anything like this for mandolin?

    https://www.stewmac.com/Luthier_Tool...Intonator.html
    Trinity College TM325 Octave Mandolin (converted to 4-string tenor guitar).
    Eastman MD-605SB, MD-604SB, MD-305, all with Grover 309 tuners.
    Eastwood 4 string electric mandostang, 2x Airline e-mandola (4-string) one strung as an e-OM.
    DSP's: Helix HX Stomp, various Zooms.
    Amps: QSC-K10, DBR-10, THR-10, Sony XB-20.

  2. #2
    Adrian Minarovic
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    Default Re: how to get perfect compensation, tool perhaps?

    Quote Originally Posted by kurth83 View Post
    Is there anything like this for mandolin?

    https://www.stewmac.com/Luthier_Tool...Intonator.html
    Why?
    Most of the time standard bridge (CA) will intonate well enough with standard setup and strings. If you really wish to cut the saddle to your exact preference you can always start with standard saddle (unless you want to intonate wound a string as in TI srings) adjust action to players preference and position of bridge so that no string sounds flat (usually that's set for best intonation of g and e or g and A) and then slowly remove tiny amounts of wood from th leading edge of bridge under the sharp pair (few strokes of fine file). Typical quality mandolin bridge has the upper saddle edges under strings almost 1/8" wide so there is room for quite an adjustment.
    You can estimate the amount of wood removal using precise tuner and calculator. Let's say the string is 5 cents sharp at 12th fret so you need to remove roughly 5/100 of the fret distance between 12th and 13th fret from the leading edge.

    edit: With all this in mind, mandolin intonation just cannot be perfect. You have pair of strings and very few players are able to press them perfectly uniformly (especially in gig situation) so one is always sharper than other and also the short scale makes it even more sensitive to bridge height vs compensation (on longer scale instruments there's no need (or minimal) to adjust compensation with minor action adjustment). We have to learn to live with these thngs as they are part of the sound. (think of "wet" tuning of accordions)
    Adrian

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  4. #3
    The Amateur Mandolinist Mark Gunter's Avatar
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    Default Re: how to get perfect compensation, tool perhaps?

    Quote Originally Posted by kurth83 View Post
    Is there anything like this for mandolin?

    https://www.stewmac.com/Luthier_Tool...Intonator.html
    No need for this with a floating bridge.
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  6. #4
    Registered User John Bertotti's Avatar
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    Default Re: how to get perfect compensation, tool perhaps?

    I could see a jig for a builder so he could dial in bridge compensation then go make the compensated bridge, especially for those guys using a CNC.
    My avatar is of my OldWave Oval A

    Creativity is just doing something wierd and finding out others like it.

  7. #5

    Default Re: how to get perfect compensation, tool perhaps?

    The issue is the Trinity College bridge which is compensated for a plain steel string on the A, so I need a new bridge. I also converted it to a tenor which makes more precise tuning desirable. The G vs D at fret 12 isn't right either, so I figured since I need a new bridge anyway, it would be nice get precise measurements.

  8. #6

    Default Re: how to get perfect compensation, tool perhaps?

    I may have found something from the electric guitar world:

    https://store.tonepros.com/p/tp6g-to...ormula-saddles

    They are found on archtop electric guitars like a Les Paul GT, used exactly the same as mando bridges, with screws to adjust height.

    Pretty sure I can make a mando bridge out of one by making a wood base with holes for the two posts, it doesn't have to be great, just enough to let me adjust the intonation, and have a real bridge made to match.


    These come in a variety of string spacings, post sizes, and radius.
    Trinity College TM325 Octave Mandolin (converted to 4-string tenor guitar).
    Eastman MD-605SB, MD-604SB, MD-305, all with Grover 309 tuners.
    Eastwood 4 string electric mandostang, 2x Airline e-mandola (4-string) one strung as an e-OM.
    DSP's: Helix HX Stomp, various Zooms.
    Amps: QSC-K10, DBR-10, THR-10, Sony XB-20.

  9. #7

    Default Re: how to get perfect compensation, tool perhaps?

    This should work just fine. Your bridge base will need to be pretty shallow since they're already over 1/2" tall. But if you can get the position and height correct, then your luthier can work off of measurements or from the physical Tune-O-Matic.

    Another option would be to make a nice plastic or wood holder for four of the tune-o-matic saddles, which would allow you to make something less clunky.

  10. #8
    Phil Goodson Philphool's Avatar
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    Default Re: how to get perfect compensation, tool perhaps?

    Quote Originally Posted by kurth83 View Post
    The issue is the Trinity College bridge which is compensated for a plain steel string on the A, so I need a new bridge. I also converted it to a tenor which makes more precise tuning desirable. The G vs D at fret 12 isn't right either, so I figured since I need a new bridge anyway, it would be nice get precise measurements.
    I had a similar problem years ago when I was using a wound 2nd. My luthier just grafted on a piece of ebony onto the front of my saddle at the A string position and fine tuned it from there. It was virtually invisible after he finished and intonation was much better.
    Phil

    “Sharps/Flats” ≠ “Accidentals”

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    Default Re: how to get perfect compensation, tool perhaps?

    edit
    Last edited by MrMoe; Jun-07-2019 at 8:08pm.

  12. #10
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    Default Re: how to get perfect compensation, tool perhaps?

    "Fine Tuning" That is what we are paid to do (as folks who work on instruments), every instrument, every bridge, and every string change, every action change, require it. I have not found any short cuts other than being a really fantastic player who can compensate with her touch.

  13. #11
    Registered User Hendrik Ahrend's Avatar
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    Default Re: how to get perfect compensation, tool perhaps?

    Kurth, just to make sure we're on the same page. On fretted string instruments (today) we strive for equal temperament. Hence, perfect intonation means that all notes are perfectly in tune with a modern electronic tuner. That in turn means that all octaves are pure (without any beats) - only the octaves are pure. However - and here is the catch - all major thirds are "too wide" for 13.7 cents (= deviation from pure in % of an equal temperament half note), and all fifths are "too narrow" for 2 cents.

    So the compromise - impure intervals except for octaves - is part of the concept. Hence, there's is no need to be all too fussy about pure intonation - other than on octaves.

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  15. #12
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    Default Re: how to get perfect compensation, tool perhaps?

    Quote Originally Posted by kurth83 View Post
    I may have found something from the electric guitar world:

    https://store.tonepros.com/p/tp6g-to...ormula-saddles

    They are found on archtop electric guitars like a Les Paul GT, used exactly the same as mando bridges, with screws to adjust height.

    Pretty sure I can make a mando bridge out of one by making a wood base with holes for the two posts, it doesn't have to be great, just enough to let me adjust the intonation, and have a real bridge made to match.


    These come in a variety of string spacings, post sizes, and radius.
    I wound up in pretty much the same situation a few years back. Did something very similar and it worked out perfect. Click image for larger version. 

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    If you haven't already worked it out...let me know and I can send you this one. Sorry about the delay, just noticed this string.

  16. #13

    Default Re: how to get perfect compensation, tool perhaps?

    Sweet, here is my version, I didn't get the string spacing quite right, but that's less important than the compensation.

    Click image for larger version. 

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    The TC OM has only about 1/2" of height, so that's the raw bridge with a few layers of index cards cutout below it to get the string height close.

    It actually plays like that, but really soft, a +24 db boost on the pickup and it sounds pretty good, slight loss of highs, but not a bad sound either. :-)

    Nice to hear it finally play in tune. I have a new set of heavier strings on order, and once it settles in a bit, I'll send the measurements off to cumberland.
    Trinity College TM325 Octave Mandolin (converted to 4-string tenor guitar).
    Eastman MD-605SB, MD-604SB, MD-305, all with Grover 309 tuners.
    Eastwood 4 string electric mandostang, 2x Airline e-mandola (4-string) one strung as an e-OM.
    DSP's: Helix HX Stomp, various Zooms.
    Amps: QSC-K10, DBR-10, THR-10, Sony XB-20.

  17. #14
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    Default Re: how to get perfect compensation, tool perhaps?

    To be clear, are you using tuneomatic saddles to set the scale lengths so you can have them cut into an ebony saddle? I've experimented w/cutting little scoops into ebony banjo saddles and it's pretty common now to see them on 3rd strings e.g. https://www.hangoutstorage.com/banjo...1619482013.jpg
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  18. #15

    Default Re: how to get perfect compensation, tool perhaps?

    Yes, the plan is to have cumberland make one with the compensation obtained from the tuneomatic bridge.

    WRT scooped bridges, the recent reposted news article on string gauges goes into detail why volin bridges (current design invented by stradivarius) are cut the way they are and answers why and how properly scooped bridges work well. See the cafe news section.
    Trinity College TM325 Octave Mandolin (converted to 4-string tenor guitar).
    Eastman MD-605SB, MD-604SB, MD-305, all with Grover 309 tuners.
    Eastwood 4 string electric mandostang, 2x Airline e-mandola (4-string) one strung as an e-OM.
    DSP's: Helix HX Stomp, various Zooms.
    Amps: QSC-K10, DBR-10, THR-10, Sony XB-20.

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