Dead spot!

Discussion in 'Basses [BG]' started by Michael Henson, Dec 20, 2005.

  1. I recently lowered the action on my Ibanez Ergodyne 5 string and now I have a dead spot at about the eighth fret. I don't want to raise the action because the feel is a thousand times better now. What are the other options for fixing this?

  2. Figjam


    Aug 5, 2003
    Boston, MA
    I belive its called a Fat Finger.
  3. scottbass

    scottbass Bass lines like a big, funky giant

    Jul 13, 2004
    Southern MN
    There are two adjustements that interact to affect playability: string height and neck bow (curvature). Check the curvature by holding down the big string - "B", if it's a 5-string bass - before the first fret (or use a capo) and also just past the last fret. The biggest gap between string and fret should occur somewhere in the middle, around the 8th to 14th fret. You should be able to just slide a business card (thin) or a credit card (thick) in the gap. Also check the thinnest - "G" - string to make sure the neck isn't warped.

    If the gap is too small, or nonexistent, you need to put more curve in the neck. You do this by loosening the adjustment nut on the headstock using an allen wrench - turn it left, or counterclockwise. Some basses use a wheel with holes around the rim instead of an allen head, and it's at the body end of the neck instead of at the headstock end. I don't know which one your bass uses.

    If the gap is too large, you need to make the neck straighter. You do this by tightening the adjustment nut or wheel - turn it right, or clockwise.

    I never adjust my neck more than 1/4 of a turn per day. Then tune it, play it, let it sit overnight, tune it again and check it again.

    Hopefully you can get those interacting adjustments - neck bow and string height - to peacefully coexist and give you an action height you like without fret buzz or dead spots.

    After you set up a few basses you actually get kinda good at it and can get them the way you want without too much trial and error. Until then, just keep trying.

    Oh yeah, when you get everything the way you want it you will have to redo the intonation by using a tuner and moving the bridge saddles to get each 12th-fret note to be in tune with its open string tuning.

    Good luck!
  4. I will try this, thanks for the advice.
  5. Vic

    Vic There's more music in the nuance than the notes. Gold Supporting Member

    Oct 14, 2002
    Central Illinois
    Staff, Bass Gear Magazine
    Interesting... I thought the original question was not about how to set up action (string height, relief, intonation), but instead, that he noticed a dead spot he never noticed before after lowering the action. :)

    Well, IMHO, I think the bad news is, a dead spot is in the instrument. Usually caused by an inconsistency in the wood in the neck (or in the neck design, but usually, it's wood imperfections).

    The reason it might be more prevalent in a lower action setup, is because that also usually means you're using/developing a lighter touch (a good thing, IMHO), in which case, the quality of the resonance of the instrument is going to be a lot more critical.

    This is the reason there is such a strong aftermarket for necks, and especially composit/graphite necks.

    Some builders use reinforcement bars to minimize risk, some builders are just super meticulous about wood selection, and some builders just consider it part of the character (as long as it's not totally stifling).

    On a higher action instrument, most folks tend to dig in a lot more, which will somewhat override a weakness in the instrument's ability to contribute to the sound, which is quite possibly why it was never noticed before.

    ...IMHO as usual...
  7. Vic

    Vic There's more music in the nuance than the notes. Gold Supporting Member

    Oct 14, 2002
    Central Illinois
    Staff, Bass Gear Magazine
    All VERY good points, Magneto. Agreed.
  8. I don't believe that deadspots are primarily caused by inconsistencies in the wood used in the neck. From what I understand these are due to resonances of the neck that correspond to the frequencies of one or more notes on the neck. This would make sense since at or near resonance the neck is going to absorb a lot of energy from the string, more than for frequencies that are far from the resonant frequency. While the wood inconsistancy could play into it, I think that it is a more general result of the shape/material of the neck. Even if the neck wood was homogenous the deadspots would still arise to the same extent.

    Here's an interesting experiment that pilotjones found.
  9. Son of Magni

    Son of Magni

    May 10, 2005
    Builder: ThorBass
    One way to help isolate this kind of problem is to try playing the same note on two different strings. Like if your 'dead' note is Db, 4th fret on the A string. Try playing the same Db, 9th fret on the E string. If it sounds dead too, then you've just identified a 'wolf note' on your instrument. If it only sounds dead on the A string, then it's likely that it's a fret related problem or a bad string or something of that sort.
  10. Vic

    Vic There's more music in the nuance than the notes. Gold Supporting Member

    Oct 14, 2002
    Central Illinois
    Staff, Bass Gear Magazine
    Wow, this is seriously interesting stuff...

    Ok, so I'd conclude then, that for an instrument to have fewer (or at least less significant) "dead spots", the resonance of the neck would have to be altered to be insignificant to the fundamental frequencies of the most typical notes played on the instrument... in other words, stiff as heck. This makes sense, and explains why, in the most extreme case, a composite neck (like my Zon) pretty much has no "dead spots" that I can tell.

    This would also explain why the dead spot would tend to be on the same note on a given design... like the C on the G string on a Fender bass (or thereabouts).

    I always figured it was because of consistency, but really, I gather it's all about resonance.

    Hope this all makes sense... it's been a long day... :)
  11. A good idea.
  12. There's an interesting discussion about some experimenting done on deadspots in this article:

    It's mostly about adding mass to the headstock or cutting it off. Adding mass to the headstock dropped the frequency of the resonance while cutting the headstock down resulted in moving the resonance up. I think it mentions that a headless P-bass they built (or essentially headless) had the deadspot moved up to about the 14th fret of the G.
  13. Vic

    Vic There's more music in the nuance than the notes. Gold Supporting Member

    Oct 14, 2002
    Central Illinois
    Staff, Bass Gear Magazine
    This makes perfect sense.