Why is my bass "knocking!?"

Discussion in 'Setup & Repair [DB]' started by burns_isaac, Dec 2, 2013.


  1. burns_isaac

    burns_isaac

    Joined:
    Jun 5, 2010
    Ok so yesterday my new "used" bass started a new buzzing sound around the tailpiece, bridge, sound post area and today after tuning up and doing some bow exercises, I moved onto some pizz stuff, as usual, and along with my first strong pizz came a very loud and at the same pitch "knocking" sound like something is banging around inside my bass at near the same pitch as the note I played. What the heck is going on!!??
     
  2. burns_isaac

    burns_isaac

    Joined:
    Jun 5, 2010
    Sound post alignment problem? I checked inside the F-holes with a flashlight and I don't see anything moving around freely and the sound post is intact.
     
  3. Greg Clinkingbeard

    Greg Clinkingbeard

    Joined:
    Apr 4, 2005
    Location:
    Kansas City area
    Disclosures:
    Setup and repair/KRUTZ Strings
  4. marvin spangles

    marvin spangles

    Joined:
    Nov 26, 2004
    Location:
    Strabane Norther Ireland.
    +1 on an open seam. It happened to me once. Took a while to discover it was an open seam in the lower bout.
    Just hope is not a loose bass bar.
     
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  6. burns_isaac

    burns_isaac

    Joined:
    Jun 5, 2010
    It is a 10 year old Karl Reiser ply so....., but I didn't see anything that looked unusual as I was just looking around again. Bowed, the bass speaks fine with no "knocking" and even a normal pizz it's fine. The knock starts happening when I start digging in. Looks like I'll be seeing the luthier this week. Thanks gentlemen.
     
  7. 360guy

    360guy

    Joined:
    Apr 28, 2006
    Location:
    Lansing, MI USA
    You could stick a light in the bass at night and look to see if you notice any light along the seams. Of course, it helps to turn off all the other lights.

    OR... Fill it with water and see if it leaks from any spots.
     
  8. basshack

    basshack

    Joined:
    Oct 18, 2011
    Location:
    Melbourne Australia
    Or you could seal up the F holes with putty and sink it in the bath and look for bubbles?
     
  9. burns_isaac

    burns_isaac

    Joined:
    Jun 5, 2010
    Ha! Just like an a/c coil when you just can't find the damn leak. Or I can just take it to Joel up in Denton and let him sort at all out. I've heard he's really good.
     
  10. burns_isaac

    burns_isaac

    Joined:
    Jun 5, 2010
    I will try the light thing. I feel ridiculous for even asking now because even if I find the problem I still have to take it to the luthier.
     
  11. fdeck

    fdeck Supporting Member

    Joined:
    Mar 20, 2004
    Location:
    Madison WI
    Disclosures:
    HPF Technology: Protecting the Pocket since 2007
    Could be the portion of the peg that goes inside your bass vibrating. That happened to me on my Kay. I diagnosed it by playing the bass without the peg. Then I shortened it by 2 inches with a hacksaw and the resonance went away. If I sell it to someone 7 feet tall, I will have to report the issue. ;)
     

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