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graphite bars inside the neck

Discussion in 'Hardware, Setup & Repair [BG]' started by Berme, Sep 9, 2001.


  1. Berme

    Berme

    May 11, 2001
    Spain
    are these narrow graphite bars inside some custom wood necks really useful for reinforcement and stability? I´m thinking of buying a Jerzy Drozd custom bass and I don´t know how these bars will really affect necks.
     
  2. Bass Guitar

    Bass Guitar Supporting Member

    Aug 13, 2001
    Graphite bars are supposed to reinforce the necks to prevent the neck from warping or changing with temperature or humidity. They are also supposed to help with dead spots. Some basses have graphite bars in the neck so that they can use softer woods to make the neck. Some believe that softer woods sound "warmer". If you are buying a custom bass, ask the luthier for more details about it. :)
     
  3. The only empirical evidence I've ever seen concerning whether graphite is good for eliminating dead spots comes from Warmoth. They claim in their website to have experimented with graphite but found that it, in fact, didn't do anything for dead spots. Hence, they only use steel reinforcements in their necks. As the owner of a Warmoth neck, I can heartily attest to the fact that this neck has NO deadspots and is the finest Fender style neck I've used to date.

    My own thoughts on this are that Warmoth is likely right in their approach. Dead spots are because the woods used in the neck manufacturing are incapable of sympathetic vibration at particular frequencies. Carbon fiber is not unlike wood in it's density though it is much stiffer than wood when assembled correctly. It is then very hard for me to believe that replacing certain parts of the wood structure in a neck with a similiarly dense material would have any affect at all in eliminating dead spots. Other add-on devices that affect dead spots are made from brass - a very dense metal - and the example they set lends support to my idea.
     
  4. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Now, I'm not an acoustics expert, and I don't offer this as gospel--but I had heard that the explanation for dead spots was the exact *opposite*. That is, that dead spots are caused by *too much* sympathetic resonance in the neck, so that the vibration in the string essentially gets "sucked up" into the neck rather than continuing to be propagated through the string. If this is so, then stiffening the neck, whether with graphite, steel or anything else, ought (all else being equal) to reduce dead spots, insofar as it keeps necks from resonating too much in response to string vibration.
     
  5. Berme

    Berme

    May 11, 2001
    Spain
    can someone explain what is exactly a dead spot? English is not my mother tongue, so there are some terms hard to figure out what they mean.:confused:
     
  6. Bass Guitar

    Bass Guitar Supporting Member

    Aug 13, 2001
    For an explanation of the definition and cause of deadspots, here is a great link:

    Acoustic Society of America - Dead Spots FAQ

    "What are "dead spots"?

    However, this long decay is not observed for each fret at which the player fingers a string. There are particular locations on the fingerboard where the sustain of a string is considerably shorter than for adjacent frets. This irregularity is well-known among players of electric basses and guitars; they call it a "dead spot". An electric guitar of the well-known Stratocaster type is chosen as an example to illustrate the effect and its diagnosis."

    Acoustic Society of America - Dead Spots FAQ
     
  7. Bermel, it's easy to describe what a dead spot is...
    especially on a Fender instrument. On your G string, play an open note and then a note at each of the frets going up. Notice how each note rings and has nice sustain and tone. Then when you get to the C#/Db/D area notice that the note sort of just thumps. That's a dead spot. It's annoying but a very common thing in a lot of basses. Fender just seems to have patented it :) and most players learn to deal with it.

    A custom bass with a laminated neck probably won't have dead spots. As a matter of fact, I've never seen a laminated neck with a dead spot at all. You will definitely notice the difference.

    Richard, the point you have made has gotten me to thinking. My first idea is that we are probably talking about the same thing. My second is that you are probably right about the orientation of where the vibration is going. My Bad :(

    But I want to be clear about the definition of stiffness. For my money, stiffness is the resistance to bending. I think that carbon fiber is great for this reason - that and the fact that the stiffness can be added without adding weight. But material density and the neck design are the biggest contributors to dead spots IMO. Replacing one fairly dense wood (i.e. maple) with a similiarly dense manmade material (carbon fiber) won't necessarily change the location or intensity of a deadspot. I wish we could get someone from Warmoth or one of the custom builders with a bit more experience to add to this discussion. I'm sure they could shed some more light on the subject.
     
  8. Berme

    Berme

    May 11, 2001
    Spain
    you guys are amazing! I mean, i don´t stop learning things here! before talking to any luthier, i´m gonna get good info about all this stuff...maybe David Pushic has something to say here!:rolleyes: Are you there, Dave?
     
  9. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Yeah, it would definitely be helpful to have one or more of those guys weigh in--I'm kind of whistling in the dark here.

    I take your point about stiffness as distinct from material density. However, I don't think density is the answer all by itself. I don't think we can assume that two identically dense materials will *necessarily* resonate in exactly the same way; I think there's more to it than that. My guess--and it's only that--is that the density, stiffness, and internal structure of the construction material, along with the way the neck is fashioned from that material, probably all play a role in the presence or absence of dead spots.
     
  10. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Gentlemen;
    the thing with dead spots is that the neck responds to the string frequency in a disfavourable manner - right?

    To avoid this, we need to alter the neck resonanse frequencies. Preferably, we raise the lowest resonance well above the basses register. Do we agree so far?

    Resonance frequency is a function of mass and stiffness, refer to the string equation, f=1/2L*sqr(T/g)
    So, to raise the resonance freq, we need to increase the quotient EI/m, that is stiffness per unit mass. Which leeds us to this thesis:

    A neck shold have high stiffnes and low mass.

    From a mechanical/acoustical approach.
     
  11. Berme

    Berme

    May 11, 2001
    Spain
    mmm...it seems that mi ideas about building a thin 7 piece purpleheart/wenge neck with 3 graphite bars inside are being confirmed as an excellent option...:) THANKS!
     
  12. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Good sound, very pretty.....Though it will be awful heavy......

    Good luck!
     
  13. yep- I agree with this.
    I've found that removing the tuner buttons (heavy Schaller cast elephant ear types) from my Fender P plus (reducing the mass at the headstock) the deadspots get moved up- ie. towards the bridge, and reduced in severity.

    I put Hipshot Ultralight tuners on my Warmoth parts bass (with (heavy)steel reinforcing rods in the neck).

    there's a slight deadspot at C# on the Gstring.

    I think that with lighter graphite reinforcement instead and the ultralights the deadspot would be moved further up- possibly eliminated.


    I think to eliminate deadspots, sympathetic vibration in the neck must be prevented.
    It can be done either by adding a lot of mass to make the neck inert (impractical due to balance issues), or by making the neck extremely stiff/rigid-eg. graphite.
    also, I think that wider/thicker necks are less prone to deadspots (eg. 5string versions of 4string basses I've tried) due to the greater stiffness due to greater cross-sectional area (and also greater mass).

    if there is still some sympathetic vibration in the neck (as on most wood or hybrid wood/graphite necks) the mass/density determines where on the neck the deadspot will show up- best further towards the bridge, as the neck is less flexible towards the neck-body joint.