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Neck reinforcement - steel bars vs carbon rods

Discussion in 'Luthier's Corner' started by Rodent, Mar 1, 2006.


  1. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    speaking of steel reinforcement bars ...

    is it just me, or do others hear a 'pinging' upper mid tonality that is only found in Warmoth necks? I find it most noticable when slapping or soloing a bridge J p/u. It's there whether I play thru a '67 Ampeg B115, a SWR Super Redhead, or an Eden WT800 + Avatar SB112 with the horn rolled all the way off. I hear this pinging no matter which bridge I use (Hipshot, Quan, stock Fender) in any flavor of materials (steel, brass, aluminum)

    this past weekend I A/B'd a Warmoth body/neck against an equally composed Sadowsky, used the same electronic set-up (OBP-1 with B/T + passive wired with backwards blend control), same strings, etc ... and it was easily (and immediately) detected by all of us testing. The only major difference between the Warmoth and Sadowsky is that Roger utilizes carbon fiber rods vs Warmoth's steel bars.

    I wonder how much the use of steel bas vs composite rods is affecting what we all heard ... any thoughts?

    BTW - this is definitely no dis on Warmoth necks

    All the best,

    R
     
  2. Maybe those steel rods are moving around just a bit? I wonder how they anchor them in....
     
  3. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    It could be the reason.
    A metal rod is uniform, i.e. the properties are the same regardless of direction (there is another word for that, but i lost it...).
    A fibre reinforced material has different properties in different directions. Just think of wood, along grain and cross grain... In a reinfoced plastic, it is even more pronounced.

    What could be behind the difference in sound is that with uniform properties, several more overtones may ring on a more equal level. Non-uniform properties will cancel some. This also includes torsional overtones, which are very peculiarly cancelled by non-uniform materials.

    It's just a thought, but theoretically very feasible.
     
  4. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    I have not idea, but AFAIK Warwick necks have steel rods, too.

    You find that "ping" sounding good or does it make it worse?
     
  5. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    carbon fiber rods are usually manufactured with a pulltrusion process, and all fiber tows are aligned along the length of the rod. when done properly, this is the ultimate manufacturing process yet for creation of a commercially available uniform property material. the cloth racks noted in this image are the exception for most pulltrusion processes I have experience with.

    [​IMG]

    steel bars have more of an isotropic grain structure than the pulltrusion carbon rods, and may contain unseen internal stresses depending on the manufacturing method utilized to 'cut/form' the strips of material.

    I can attest that the steel bars in a Warmoth neck are not loose, as they are solidly epoxied in place.

    To my ear, this pinging is excellent for those who are looking for a more mordern sound, and a note in the 'not so hot' column for those looking for something more traditionally old school. I receive the same commentary from a couple of players who have been taken my prototype basses out for test spins.
     
  6. I am constantly amazed at the level of experience and intelligence one finds in this forum on a daily basis. There are great people here!
     
  7. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    The fact that the pultrusion process works the way it does means that carbon composite rods are inherently highly anisotropic in their properties. They are uniform in composition, but not in properties with respect to direction, the way Sub meant.

    As to Sub's conjecture about the generally isotropic properties contributing to ringing, I can't comment.
     
  8. Rodent and pilotjones got it, but you're looking for isotropic. I wish that more things were isotropic, specifically plasmas in magnetic fields. (Looks over at tokamak and shakes fist) I'M TALKING ABOUT YOU!!!

    :eek: :D

    I really need to go home.
     
  9. *** is tokamak?
     
  10. It's a nuclear fusion device:

    http://en.wikipedia.org/wiki/Tokamak

    Here's a cutaway image of JET (largest in the world right now) and ITER (soon to be built in France, twice as large as JET in almost every dimension).

    [​IMG]
     
  11. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Yeah, isotropic is the word I lost.

    And Rodent is right, different production processes will alter the isotropicity:)eek: ??) of a plate - but it will be very much more isotropic than a pulltruded fibre bar.
    Which may induce a different set of overtones, and the difference in the quotient mass/stiffness does indeed mean a different set of overtones.