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Bumps from the soundpost...

Discussion in 'Setup & Repair [DB]' started by EthanTheBassist, Mar 27, 2009.

  1. So on my laminate DB, there is a small bump on the front and back of my bass where the soundpost is. You can feel it slightly if you run your hand over it, but I notice it most when I get it at the correct angle with light and you can see the light bend around the bump. There is no cracking. Should I be worried? (I thought it was called doming or something like that.) Thanks in advance!

    I didn't find anything on this topic in the 16 pages of posts but I could swear I've read it somewhere.
  2. Ethan

    you could have a potentially really serious issue there. your soundpost is either not fitted correctly or, if cut correctly, is not set correctly. i have a fully carved bass and my luthier told me that that can do permanent damage to the top.

    if it were me, i would loosen the strings immediately, like NOW, to take the pressure off.

    using a mirror and small halogen light to see the underside of the top through the ff holes, you can check whether the SP is tilted. if you see any gaps between the ends of the SP and the top or back, then the SP is not flush with the inside surfaces. that's the easier situation -- just not set well. it may be just a matter of straightening it out. a luther can do that for you. or you can tap it gently into place. then re-tighten your strings and look again to check for gaps. it has to be perfectly flush on both ends.

    but if the soundpost itself is too pointed or otherwise not cut correctly, you have a bad situation. if it were me i would, as a precautionary measure in that case, remove the sound post until you can go to a good luthier to get this soundpost fixed or a new one fitted.

    hope it works out for you...

  3. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    Well actually that's quite common ... I don't think you need to panic. It won't crack your top because you have a laminated bass, but it might get worse over time as it pushes the top out of shape. You'll probably notice the ffs sinking a bit on the other side, too.

    Lots of ply basses have an extra 4" disk of ply or spruce laminated into the back which distributes the sound post pressure more evenly and reduces the bump. You can get that done. Probably won't affect the sound in a bad way.
    Mike Law likes this.
  4. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    The best thing you can do is get it to a luthier. I agree about loosening the strings. I'd do that as a precaution although, as Matthew points out, there is not likely to be immediate disaster. As for the fitting of the post, well, if it's anything more than it being out of the position for which it was cut, then it's not easy at all. That would mean it's sitting "en pointe" (an angled surface pressing against the top or back, see here) or it's just too tight. Even if it's simply out of its position, it would be best to have a luthier reset it. Unless you have a soundpost setting tool and know what you're doing, you're not likely to get it right. To me anyway, soundpost setting is like transmission repair on a car. It's just not for a DIYer operation.
  5. Good article by Jeff. Thanks for the link.

    Standing "en pointe" is what I meant by a well fitted SP that is standing tilted and the edges can "cut" into the top. That is the easier situtation. It just needs resetting.

    But I don't think one has to take the view that you can't reset the SP yourself. I am not a luthier but I have reset my soundposts on several basses by myself on numerous occasions. I got a SP-setting tool set and it works fine. It's not rocket science and quite do-able.

    Now carving and fitting a new SP, now that would take (for me) time, effort, and skill to get the right length and surface fit on the ends. My luthier fit one for me in about 10 minutes... but he's been doing it for 40 years or more.
  6. Jake deVilliers

    Jake deVilliers Commercial User

    May 24, 2006
    Crescent Beach, BC
    Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
    I've seen a few plywood DBs with cracks front and back from over-sized soundposts. They aren't very easy to repair. :(

    To the OP - please take your instrument to an experienced bass repairperson for evaluation - it might be nothing, it might be that your soundpost needs to be a little shorter... :)
  7. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Well, you're braver than I am and likely much more talented with wood. I'm curious, did you reset your sound posts because they moved-- as in somehow got nudged out of position or shifted during string changing? Was it that you just wanted to try a slightly new position?

    I always took to heart what Jeff says in his "rant:"

    It takes me about an hour to accurately fit a post. If someone fits a post in 5 minutes they are either an unbelievable genius or a charlatan.

    Please don't misunderstand, I mean no slight to your luthier or anyone else. When I've had a new sound post fit, they've pulled the endpin so that they could get a good look at the position through the hole in the endblock. It always took 45 min to an hour because of that last bit of adjustment to get the fit just right using completely flat ends with no rounding of the edges of the post. It seemed like 90% of the fit was done in 15-20 minutes with the last 10% taking the rest of the time.

    To me, that stuff is like rocket science. I know my limits! :)

    I admire folks like yourself who can do this kind of work.
  8. Thanks everybody! I think when I get a chance I will take it down to a guy I just found in eugene (Oregon) that repairs stringed instruments. Any idea how much things like this cost?
    Thanks again!
  9. Oh, and real quick I've always wanted to know: Are carved DB's heavier than laminate/plywood DB's? Thanks.
  10. vejesse


    Apr 8, 2006
    Madison, Wi
    Double Bass Workshop
    Pulling the endpin to look at the soundpost fit? So, do you drill a 1.5" inch hole through the neck block to get a look at the other side?
  11. jallenbass

    jallenbass Supporting Member Commercial User

    May 17, 2005
    Bend, Oregon
    I believe he means that one can see whether the soundpost is straight up and down on that particular axis.
  12. zeytoun


    Dec 19, 2008
    Portland, Oregon
    Depends on the quantities and densities of the woods used.

  13. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Oh, how clever! :scowl:

    I think what I said was pretty clear:
    Just as jallenbass said, the idea is that you can see very clearly if the soundpost is straight along the left/right axis and the view also provides a detailed look at the fit against the plates. I don't know that it's done every time but it sure made sense to me. Look:
  14. E.P. Miller

    E.P. Miller Supporting Member

    Nov 17, 2008
    This is the only thing you need to do. I had the same problem with a bass years ago. The person who set the soundpost told me the top was to thin and that was causing the problem. Another person told me the soundpost was cut too long and was putting too much pressure on the bottom side of the top table. The truth is in there somewhere. Either way, it's totally correctable but you must act quickly...
  15. vejesse


    Apr 8, 2006
    Madison, Wi
    Double Bass Workshop
    ok, ok. Sure I can see it. Didn't mean to offend. It's just that when I set a soundpost, unless I'm fitting a new post in conjunction with a new bridge I tend to do the fitting work when the other work is done and the bass is ready to be strung up. The tailwire is around the endpin plug, the bridge is in position on the top and strings are over the bridge.

    You know the sides of the endpin and neck blocks are usually pretty closely perpendicular to the top. With a 2" x 3" mechanics mirror you can see the side of the post in relation to the edge of the blocks easily.
  16. Thanks everybody! I'm gonna get it to a luthier asap and hopefully not blow my entire college savings.
  17. Drurb,

    i reset my soundpost a few times when it fell over, taking the opportunity to reset it in a slightly different spot. With the right tools it is really not so difficult.

    One of the biggest problems is having enough light in there to see. As you point out, the end pin hole can provide the right perspective. On one of my basses, the TP cord does not go around the endpin but around another separate button-like thing. So its easy to remove the endpin and have a look at the soundpost.

    As for the time involved, it was already about 4 years ago that i had my luther cut and fit a new soundpost from a blank, and i must say it probably was not 10 minutes but more like 45. in retrospect, however, it seemed at the time he worked quickly. i was quite impressed. i would not do that task myself, btw.

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