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Soundpost diameter

Discussion in 'Setup & Repair [DB]' started by MIKMAN, Jun 20, 2008.



    Mar 4, 2008
    Larisa, Greece
    Dear friends, i'm experimenting with the soundpost in my new double bass. I have bought a Tempel soundpost, diameter 20mm, which is 2 mm thicker than the original. How does the soundpost thickness affect the tone? From my experience with the violin's lutherie the thicker soundpost transfers much better the vibrations from the bridge to the back plate of the violin. Is it valid for the double bass?
    Thanks in advance
  2. My experience is that the two biggest factors on doublebass soundposts are (1) good fit and (2) density of the wood in the soundpost. Diameter would be a distant third IMO. Most commercially made soundpost blanks are of medium density spruce which is a good compromise for most basses. However, I've found many instruments sound better with a lighter, less dense post while a lesser number sound better with a heavier, more dense post. It's strictly a matter of trial and error. There are no set in stone rules for which works best on a given bass.
    riimodar likes this.
  3. Bob,

    Have you found any characteristics in basses that might indicate which type of post would work better in a particular instance or does it seem completely random?
  4. Gearhead43


    Nov 25, 2007
    Mr. Branstetter seemed to answer that one already.

    "It's strictly a matter of trial and error. There are no set in stone rules for which works best on a given bass."
  5. ^^^ Nice contribution. I was wondering something along the lines of if the trial and error applied on a bass-to-bass basis (sorry) or if there might be some common thread, say "I might start with soundpost X because this bass displays Y physical or tonal characteristic, and go from there". Y being something like, say, a thicker than normal top plate, a particular style of graduation, A bass that's overly tight/loose or bright/dark, etc.

    Not really looking for something like "Thick soundposts make plywood basses better". :rolleyes:
  6. I would probably try a lighter soundpost first simply because it has been my experience that more basses sound better with a lighter soundpost than with a heavier post. However, I MIGHT start with a heavier post if the bass was extremely dark and the owner wants it brighter. Even then, there is no guarantee that heavier will be better. Every bass is different. It really is a trial and error procedure (at least it is for me).

    The difference that soundpost density can make was shown to me by my late mentor who was a world class violin maker. Many of the good violin makers I know prefer to make their own posts rather than using commercially made soundpost blanks. (Before anyone asks, I don't know of any commercial supplier that grades bass soundpost blanks by anything other than diameter. I make my own.)
  7. Thank you sir! :D
  8. Gearhead43


    Nov 25, 2007

    If you happen to look here again I have a quick soundpost question.

    Would swapping out the stock soundpost on a ply bass, like my Engelhardt, for a better quality one, most likely improve the sound? If so, in what way? (hypothetically speaking)

    I know very little about soundpost woods, and how one type can be better than another. I assume there are "grades" of spruce blanks?

    My bass had a basic setup by an unknown luthier, but I am pretty sure the stock soundpost was left in place. I am trying to ascertain if it would be worth the expense. If it may improve the sound by a good margin I will go for it.

    Jeff Sahs is in my neighborhood, so I have a good luthier to take my bass to.

    Thanks for any input.
  9. Gearhead43


    Nov 25, 2007
    Well, I read and read until I gave myself a headache on different theories on soundpost diameters, materials, etc. Bobs posts seem to indicate that it's the fit & placement that is the most important thing, maybe not the "grade" of wood so much.

    I may still have my post adjusted, meaning a new one made for a possible better position, if Jeff Sahs thinks my bass would need it. I need to see how booked up he is.

  10. Heifetzbass

    Heifetzbass Commercial User

    Feb 6, 2004
    Upstate, SC
    Owner, Gencarelli Bass Works and Fine String Instruments, LLC.
    Hey Bob,

    I was wondering if you could be a little more specific on the "lighter vs heavier"? Could you give a weight range? I realize if a post is longer or shorter it could affect the weight, but if two were the same length, what would the difference be?

    If not, no worries.

  11. I'm really more concerned with density rather than weight. The easiest test I know of is to see how much you can dent the wood with your thumb nail. You can make a fairly deep impression in a soft, less dense wood and will you barely dent a harder, more dense wood.
  12. The best advice I can give anyone about soundposts is to take your instrument to an experienced doublebass luthier and let him examine your bass on his table and then follow what he recommends for your particular instrument. Every bass is different.
  13. Gearhead43


    Nov 25, 2007
    Gotcha, thanks Bob!