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piezo response adjustment

Discussion in 'Electric Upright Basses (EUB's) [DB]' started by jayscheuerle, Dec 19, 2012.

  1. I'm working to add a piezo strip under my solid bridge. In general, the sound is good, and it's built so that the E end is more sensitive than the G (you can really tell the difference if the strip is flipped). My problem is that the G side is still a little loud and I'd like to even it out via the construction, not electronics.

    Would any of these methods work or do you have any other ideas?

    1) shave the underside of the G end down enough to replace a 1/16" deep section of wood of along the bottom with a 1/16" thick piece of cork

    2) carve a curve on the underside of the bridge where the G string would be transmitting its vibrations directly so that they go to either side, focusing the energy on the edge of the bridge and more towards the pickup section under the D string.

    3) drill a large (3/8" or so?) hole in the bridge under the G string, rerouting the energy so that it still uses the area under the G string, but it's not as direct.

    4) put a small piece of cork between the G string and the bridge.

    Any thoughts would be appreciated !- j
  2. Can you put a pic of the setup?
    How tall is the bridge?
  3. This pic doesn't show the pickup, but the bridge is maybe .75" high on the ends and 1.25" in the middle.

    Attached Files:

  4. Is there a routing under the bridge?
    If not, I'd try a single element from a Fishman BP-100 between a foot and the bass top. (or even the two of them, one at each side, like the KYDD bass)
  5. I've got a pickup I like. I'm just trying to reduce the response on the higher end.
  6. I understand.
    However the solution may be another pickup.
    I'm playing on EUBs since a good while and did a lot of experimenting.
    A short bridge like that may be more difficult to work with.
  7. Steve Dallman

    Steve Dallman Supporting Member

    There's a trick that evens the response of a pickup that was developed for use with a B-band, but I've used it successfully with other piezos, including separate element, continuous strip, or piezo rope types.

    Get some self-hardening clay from a craft or hobby store. You don't need much. Make a thin strip. I usually roll out some with a rolling pin and cut thin strips with an Xacto knife.

    Put a thin strip of clay between the pickup and saddle. Tighten the strings to force the clay in, and wait a day or two.

    This has worked for me. In difficult cases I've put the clay on below and above the piezo. I also take the saddle down to compensate for the thickness of the clay, although if done properly, the clay adds little to no thickness.

    And, most importantly, clean the rolling pin before the clay dries. (Don't ask me how I know this...my wife can tell you.)

    The clay is removable. If unsuccessful, the saddle and pickup can be removed, the clay can be picked out, and the remainder can be removed with a damp cloth.