'Tweaking' a soundpost?

Discussion in 'Basses [DB]' started by Greywoulf, Feb 26, 2004.

  1. What does it mean to tweak, or adjust, a soundpost when a luthier does it in a setup? I had thought the soundpost was inside the bass, inside the body, behind the lower neck? Am I mistaken about this?

    And if I'm not, then how is it adjusted? Does the bass have to be taken apart to get at this soundpost? Also, why is it done? Are many soundposts too large or too small or in the wrong place, etc, for the best tone? I mean, wouldn't having a soundpost set up correctly in the first place be something absolutely essential for a bass builder?

    Greywoulf :confused:
  2. Search under Sound Post...Just to get you goin', the sound post is a dowel like wooden post that is held upright, right below your basse's treble side, or G side by string pressure on the bridge, on the inside. No glue, nails, screws or chewing gum help it stay suspended....just the string pressure on the bridge. Its job is to help the top not to cave in and to transfer the sound from the top plates to the back plates and move the vibrations around the inside of the bass. To "tweak" the sound just means to move the sound post around the inside of the bass with couple of specialized tools from the outside of the bass. The post, after the strings are detuned taking off the pressure, is moved around...up, down, left and right to achive the sound you're looking for....in terms of darker, less dark, brighter, more cutting, more or less sustain, etc. The catch, even though the bass is laying on it's back, is that while doing this, the sound post falls and you have to chase it around the inside of the bass with pinchers and grabbers, mirrors and whatever. Once you retrieve it, you have to start all over again, bearing in mind that the post end or ends in the case of a carved back are cut to match the arching on the bass top. A flatback is easier because the back end of the post is flat. You have to make sure that the angle cut on the post matches EXACTLY the arching on the top.And/or back!
    You could do some MAJOR damage to your bass by doing this. You need the tools...a complete sound post setting kit. But don't even think about trying it with no experience! :help: Call your luthier!!!!
  3. Thanks Paul... I did the search on "sound post" and came up with 30 pages! (...And each page of course with multiple topics!) But I searched thru and quickly lucked out by coming up with a posting that included the below link to David Gage's site, which has several good articles about setups, including the sound post thing.
    So I'm linking it again here for anyone else who might come thru this thread......


    Greywoulf :hyper:
  4. Like Paul said, a flatback bass is easier. I've messed around with mine a bit just to see what would happen. Never really did much good, but gave me a bit of an idea how it works. I used a small inspection mirror and a long metal spatula (the kind you flip burgers with) to tap it around. Note that I never moved it more than a quarter inch or so, because I figured the shape would need to be adjusted to meet the arching if I moved it much more than that... Also if you plan on moving yours, I would suggest marking it's original location with a pencil so you can put it back if need be.
  5. I know it's only human to be curious, and i'm one of those people who seemingly HAS to know how some things work. I'm not a luthier! I used to do alot of adjusting, so I'm not bad at post setting, a little bridge work. I'm best at how to achieve my sound as in post/bridge movement as it relates to sound and feel. This took me maybe 30 yrs.!
    Ideally it wood be nice to have an old clunker just to experiment on. My problem is that this would have to be a decent, carved, clunker to do all the "fun" things on. The bass, for me, has to be responsive enough to pull out of it all the things I want. For instance, Red Mitchell used to set his SP with a VU meter on a good tape recorder! This was in the days of high action and gut strings, so it was possible. Now days, it probably wouldn't even work.
    I guess my point is, chasing a SP around the inside of a bass isn't some peoples idea of a good time and you can really mess up a soft, spruce top by forcing a post in at the wrong angle. I've seen insides of tops that were cracked by forcing a post that was carved for exact fitting for the arching on the top. If you love your bass, take it to a PRO!