Why is my MIM neck more sensitive to humidity than my MIJ P-bass?

Discussion in 'Basses [BG]' started by Just go for it, May 9, 2021.

  1. Does anyone have an explanation for this?
  2. Maxdusty


    Mar 9, 2012
    Michigan USA
    I can speculate... wood used in the MIJ is perhaps a little better seasoned to deal with humid climates than the one in that particular MIM.
    I grew up there and I know pianos and sometimes some guitars bought in the US have to acclimatize when transported to Asia to deal with the humid climates, not all, but some.
    Last edited: May 9, 2021
    Chrisk-K, Dabndug and vindibona1 like this.
  3. dabbler


    Aug 17, 2007
    Bowie, MD
    Not sure but 2 questions will get the discussion started:

    1. Which neck is thicker (front to back).
    2. Do they have the same type (rounds/flats), brand and gauge of strings?
    DaveDeVille and erratick like this.
  4. 1. The MIJ is thicker, the MIM is the Nate Mendel model.
    2. Same strings on both basses (Elixir Strings Nanoweb Light/Medium .045 - .105)
  5. dabbler


    Aug 17, 2007
    Bowie, MD
    I would expect a thinner neck to be more susceptible to environmental factors, everything else bring equal.
  6. Strangely, my Yamaha and Ibanez basses are not bothered by it either. And these necks are even thinner.
    Yahboy likes this.
  7. Maxdusty


    Mar 9, 2012
    Michigan USA
    I live in Michigan, summers are hot and humid, winters are cold, really cold....my Yamaha basses when I had them were indeed pretty stable year round, some of the Ibanez basses I've owned were more affected by the change than Fender, the worst were the old Ibanez SR300 version with the 3 piece necks(I had two of them). They needed constant tweaks. The newer SR300 and SR300E models, the 5 piece necks were more stable.
    shodan likes this.
  8. RattleSnack


    Sep 22, 2011
    As far as I understand, it's air humidity that makes neck unstable. Fretboard wood soaks water and expands, pushing neck to backbow. And it's also other way around, if it dries out, it shrinks and pulls neck into forward bow.
    If one of your guitars has maple fretboard and it has finish on it, it will soak very little water making neck more stable.
    That is one of reasons I prefer finished maple over unfinished rosewood for fingerboard. In my experience, this GENERALY makes guitars with maple fretboard more stable.
  9. The thing is, adjusting the NM neck is a hell of a job.
  10. In Japan they often build guitars differently to deal with the high humidity. Yairi acoustics are sometimes if not often with laminated backs and sides because of the humidity, not to make cheaper guitars. I'm not sure how they basses might be constructed differently.

    That makes sense. My humidifier struggled all winter to maintain 40% IRH and I turned it off a month ago where the humidity dropped a bit and had difficulty getting straightening the neck of my Jazz5/RW (the TR adjustment is super stiff which doesn't help). We had an increase in humidity later last month and the relief dropped to the point where I almost had to loosen the TR, only to have a bit of a humidity drop and my J5 is now where is should be. However, the neck on my Yamaha TRBX605 with RW (made in Indonesia) has remained pretty stable all year. I haven't checked my J4/maple as it lives in the closet because I have little use for a 4 banger any more.
    RattleSnack likes this.
  11. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    If the neck is thinner back to front, there's less wood to combat the tension. But also likely that the MIJ used better wood and/or seasoned it better.
    Son of Wobble likes this.
  12. Samatza


    Apr 15, 2019
    There are a few factors at play, are the fretboard woods the same species?

    Ebony has a tendency to react more, maple less and rosewood somewhere in the middle.

    Basses with graphite reinforcement are more stable. Properly dried woods are also less reactive.
  13. Different personalities
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  14. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    Wood can vary a lot in quality within the same species, and thus will react differently to changes in humidity. Different finishes will have varying degrees of protection against moisture ingress/egress. Then, of course, differences in geometry of the necks will also affect how they react.
  15. Bloomfield


    Jan 21, 2020
    Nova Scotia
    Look at the end grain at the headstock or heel; are the growth rings oriented the same? The cut of the wood could have something to do with it.
    One Way and 31HZ like this.
  16. AboutSweetSue


    Sep 29, 2018
    There could be multiple reasons. What year are these basses?

    You could take a pic of the necks. Some wood grain detectives could possibly tell you.
  17. cxcxcx


    Mar 8, 2019
    It’s largely due to the drying process that the lumber used to make the neck goes through - the wood in modern guitars built under certain price points won’t be as as dry and as close to moisture equilibrium as it could/should be - fully dried lumber is part of what you pay for in a high-dollar guitar. You don’t get noodle necks from builders like Smith, Sadowsky, or Suhr because they pay strict attention to the wood they use before a saw blade ever comes near it.

    In the case of many Fender designs, wood compression and a known issue with the truss rod design can make a neck particularly wonky and require a lot of adjustment. In many instances, a few well-placed truss rod washers inside the neck before the adjuster nut can make up for some missing space and totally fix an otherwise unreliable neck that can’t hold a setup. You can Google “Fender truss rod washers” and find them all over.
    Last edited: May 9, 2021
  18. Thank you all for your input so far.
  19. micguy


    May 17, 2011
    Wood and steel expand differently with temperature and humidity changes. If you have a thick, stable (meaning the internal stresses have been relieved by time or proper seasoning) wood neck that takes most of the tension without needing much help from the truss rod, you'll have a more stable neck.

    The most stable neck I ever had was a Kramer aluminum (duh) - those don't have a truss rod; they're so frickin' stiff there simply is no need. Second best are my roasted maple Warmoth 5's - fairiy thick (and wide), very stable wood (roasting helps considerably in relieving internal stresses in wood), and stiff enough that they don't need much help from the truss rod. In summer, I think they'd be just fine without a truss rod. In Winter, you give the thing a quarter turn, and you're there.
  20. Maxdusty


    Mar 9, 2012
    Michigan USA
    There's a post here on TB a while back about the MIJ Fender necks typically having more of a finish coating on the back of their necks than the MIM or even the US Fender necks so better protection against the effects of moisture and humidity. Don't know if that's true but come to think of it, the MIJ necks I've seen do seem to have a thicker coating of finish on them. That on top of use of better seasoned wood probably makes for more stable necks.
    Fialka and kjp360 like this.
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