2 Same Guitars. Same Everything. Identical. Different Tension?

Discussion in 'Guitars in General' started by ruger9, Feb 14, 2020.

  1. Timtam

    Timtam Member

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    You misunderstood what Frudua said. There is a difference between string tension (entirely determined by tuning, mass per unit length, and scale length .. therefore only the string between the nut and bridge), and string stiffness (the force required to change string length* ... the inverse of string compliance ... and affected by additional factors, including the string length / geometry beyond the nut and the bridge). (Frudua calls stiffness 'hardness' ... lost in Italian-English translation ?).
    Try these ..
    http://www.noyceguitars.com/technotes/articles/t3.html
    https://www.liutaiomottola.com/myth/perception.htm

    * so ... fretting and bending 'feel'

    I might also say that while the stiffness of the neck (the combination of wood stiffness and specific dialled-in truss rod stiffness) might theoretically affect playing 'feel' of the strings, I know of no direct evidence to support this. Certainly some necks can be very stiff. But if others are very flexible, every fretted note would go out of tune just due to the act of fretting it, due to the neck bending. So there is a small window in which a neck can be flexible without affecting its operation. As I said, whether this narrow window is perceptible in general playing, on top of the other stiffness/'feel' factors, is AFAIK unknown.

    There is some experimental science on neck stiffness, but not much ... eg
    http://leonardo-guitar-research.com/Guitar_neck_stability_and_stiffness_tests.pdf
    It has shown for example that beliefs about quartersawn necks being stiffer are not necessarily true.
    https://www.liutaiomottola.com/myth/quartersawn.htm
    https://www.barbarossa-guitars.com/misc/Articles/2017-01-13/Bending_Test_Article_25-Mar-2016.pdf
     
    Last edited: Feb 14, 2020
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  2. ruger9

    ruger9 Member

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    WOW.... ton of info in those links!
     
  3. hotrats73

    hotrats73 Member

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    If everything is equal my guess is that neck profile is different.
     
  4. ruger9

    ruger9 Member

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    Well, as I said earlier.... they are both Fender Modern C maple necks. One is MIA one is MIM, and the MIM one seems to be a TINY BIT thicker- like 1mm maybe (using a micrometer)... but it's definitely "feel"-able. It's also the stiffer of the 2.
     
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  5. korus

    korus Member

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    Which neck has the truss-rod tightened more for the same relief? Stiffer one?

    All other elements being equal, the one with tighter truss rod sounds brighter (less low end to eacb tone, mostly) unplugged also.

    (you can turn each 1/4 or 1/8 turn tighter and back to exact same position to find which one 'fights' more)
     
    Last edited: Feb 15, 2020
  6. K-Line

    K-Line Vendor

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    Every piece of wood is different.
     
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  7. ruger9

    ruger9 Member

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    That I'm not sure of. I *think* the stiffer one, as the looser one's truss rod is barely engaged, if I remember correctly. That guitar is 25 years old, the stiffer one is only about 6 years old.

    actually, if what I said above is true (about the true rods)- the stiffer one is NOT brighter, and has MORE bass than the looser one. However- now you're moving into TONE territory, and there's a lot of factors there... wood species, guitar weight, pickups....
     
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  8. korus

    korus Member

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    You're right my bad. Part on tone is competely obsolete, ignore it.
     
  9. CaptNasty

    CaptNasty Member

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    @Timtam is on point with this post.

    String tension = the amount of stress (i.e. pulling force) required to elongate a string to a target vibrating frequency (i.e. pitch).
    https://en.wikipedia.org/wiki/Tension_(physics)

    String stiffness (i.e. perceived tension) = the amount of force required to fret or bend a note.
    https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0102088

    Given two instruments of the same scale length, using the same tuning, and strings of the same gauge the string tension will be the same however the string stiffness can vary due to a number of factors including but not necessarily limited to:
    • Bridge height
    • Nut height
    • Neck relief
    • Neck width
    • Neck thickness
    • Neck shape
    • Break angle over the nut
    • Nut type (i.e. locking vs slotted)
    • Stiffness of the bridge (i.e. hardtail versus tremolo bridge)
    • Condition of frets (i.e. polished, corroded, pitted, worn, or divotted)
    • Player specific techniques and reactions to individual instruments
     
  10. kuhboom

    kuhboom Member

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    Another big factor in string compliance with bolt on guitars is neck pocket depth, which will affect the break angle over the bridge / saddles. even a slightly deeper neck pocket can make the guitar feel much slinkier.
     
  11. Sweetfinger

    Sweetfinger Silver Supporting Member

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    The two things I'd look at were the wood in the necks and the profile. Even a slightly different profile, radius, or fretwire will make the hand move through repetitive motions in slightly different places. Your hand, just like a car, will have "power bands", defined by musculature, ligaments, and the geometry of the bones and tendons. If a different neck profile or fret height, etc., moves, say, a full step string bend just slightly into or out of your hand's strong spot, that guitar will feel easier, or stiffer, all else being equal.
    If one of the necks is cut from a stiffer piece of lumber, that will affect the feel of the guitar. Depending on the player, they may feel it as stiffer, or easier.
    I have a customer who has two similar acoustics and has tried for years to force the stiffer feeling one to play like the softer one. We've gotten them close, enough that most people can't feel a difference, but he measures it by how long he can play one at a gig before his hands get tired. The softer one he can play all night. The stiffer one, a set, set and a half.
    Guitars are such low tolerance constructs from an engineering standpoint, and the materials used (wood), are inconsistent enough, even when cut from the same log, that finding two identical examples or trying to manufacture identical "peas in a pod", are just not attainable through methods other than luck. Sure, you can entirely re-think the electric guitar and employ non-traditional manufacturing and use modern materials but you end up with instruments that players simply don't like.
    The takeaway is that there's a point where you've done what you can and either accept fate, or drive yourself, and others mad.
     
  12. BADHAK

    BADHAK Member

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    What a strange post
     
  13. CaptNasty

    CaptNasty Member

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    What a worthless post...

    You’ve added nothing to this thread other than an off topic snipe. Bravo!
     
    Last edited: Feb 21, 2020
  14. VaughnC

    VaughnC Supporting Member

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    IMO, the amount of "feel tension" of the strings is related to the inherent pliability of the individual piece of neck wood and the amount of trussrod tension needed to obtain proper fretboard relief.
     
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  15. Adaptandovercome

    Adaptandovercome Member

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    For the question on string tension, 2 exact guitars maybe but think about two Siamese twins the only thing exact was the father and mother? Onto the tuners take a close look could one set be staggered height to achieve tone and pitch each guitar will have its own preferred setting to achieve that there's no getting around it.
     
  16. icr

    icr Member

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    Fantastic find!! Now if you can connect the higher tension string to the lower tension string you can create a perpetual motion machine and harvest unlimited energy!
     
  17. ruger9

    ruger9 Member

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    /Thread. LOL

    I was never worried about, and certainly not driving myself crazy over nuances... I was just interested in talking about it, I like learning stuff. But yes- so much of this crap can drive you insane. I no longer sweat the small stuff. In the end, it comes down to "do I like the guitar? I do? Good, then play it."
     
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  18. cr7r9

    cr7r9 Member

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    Is it possible that one or more of the strings are not tuned exactly to the same pitch as the other guitar?
     
  19. Dave Weir

    Dave Weir Gold Supporting Member

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    It’s pretty easy to compare the stiffness of two necks.
    Tune them both, then tune D to G. See how that affects the other strings.
    I suspect the results will be similar, but check it out. Then you can confirm or rule out neck flex.
    The things I notice most are friction points at or past the nut and bridge, and fret size.
     
  20. korus

    korus Member

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    So the questions coming from this thread might be :

    Is the guitar with stiffer feel of 2 identical ones (same construction, same setup) always the one which have strings HIGHER above body top/pickguard?

    And a question for regular (bottom fed strings) Teles:

    which friction of strings with metal part is greater : at saddle slot or at bridge plate hole? Which break angle of these 2 should be primarily made less steep (while making the other one more steep, obviously) to reduce stiffness of strings more than the other way round?

    My estimate that friction is greater at saddle so strings on Tele become less stiff when intonated position of saddles is further away from bridge plate holes.
     
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