Bridge placement and tone

Discussion in 'Setup & Repair [DB]' started by m2habert, Aug 5, 2009.

  1. m2habert


    Aug 5, 2009
    Hi there, new to the forum. And new to the DB world of self-induced neurosis.

    Two days ago, I took my DB to a friend who has a lot of experience and is a very excellent and successfull player. I wanted some feedback on my new Spiros and string height, and my biggest complaint was how mid-rangy the instrument was sounding. Some regions (specially the A string at the C-Eb position) sounded dreadfull, really.

    He made fun of me and said I was exagerating, and nitpicking. But he complained about the position of the strings in relation to the fingerboard, saying there was no room for the G string.

    Before I could say anything, he gets a siliconed hammer and bumps the bridge sideways! The bridge slided towards the E string f-hole something about 2.5 mm from its orginal centered position (it has been recently centered by a luthier, and we marked with pencil its "rightfull" place).

    He got pleased with the new position of the strings. It felt better to me, too. But I couldn't believe how much better the bass was sounding!! The awful midrangeness is gone, and the sound is now perfect!! I have more bass too! Less twanginess!

    I'm really curious about this. For starters, ¿why would there be more bass if the bridge is now away from the soundpost?

    I googled about this and didn't find any comments on experimentation on bridge placement. Can't find it here in the forum as well. ¿¿Anybody ever heard about messing up with the center position of the bridge?? I'm very pleased with my sound now, but would like further knowledge for when I upgrade to better bridges...
  2. Damon Rondeau

    Damon Rondeau Journeyman Clam Artist Supporting Member

    Nov 19, 2002
    Winnipeg, baby
    25 mm?? That's one inch. A lot.
  3. Eric Hochberg

    Eric Hochberg

    Jul 7, 2004
    Good info here. If your bridge is that far off center now, it sounds as if your neck might not on straight.
  4. m2habert


    Aug 5, 2009
    sorry, typo/hurry: I meant 2.5 mm.
  5. Gearhead43


    Nov 25, 2007
    If your soundpost is now oriented more towards the outside edge of the treble bridge foot, then those results would make sense.

    You should have the bridge centered, and the soundpost adjusted from there, by a good luthier.
  6. m2habert


    Aug 5, 2009
    That's exactly my reasoning... But, it's oriented towards the bass bridge foot/f-hole. Really would like to know more about this with people who have messed up with this aspect...

    Man, I'm not touching it, the sound and feel are perfect. The sound post is in the exact position setted by the maker. The bridge may have been badly screwed by one of the luthiers when he setted up the threaded wheels.) My problem is exaclty that: luthiers wanting to belittle the maker's work so they can blame their rushed up work on somebody else. (going to the maker means a 4 hour drive. I've already switched to a second more careful luthier, but he also has this bad habit of depreciating the maker's work).

    But, as often said, DB is no exact science... I may have to resort to this "trick" in the future, when upgrading to a better bridge.
  7. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    Well, if the neck is not straight, then its understandable for both your luthiers to be a little critical of the maker's work ... and I wouldn't assume that the sound post is in the right spot.

    So check it. Its very easy to see where things should be.

    1. The bridge should be centered between the inner FF nicks and equidistant from the FFs on both sides

    2. The fingerboard should be straight and centered between the FFs when viewed from the front. You can measure from the corners of the fingerboard to the corresponding FF hole eye to check.

    3. The strings when in their in their slots should be evenly spaced and over the fingerboard from end to end. Your E and G should have at least 6mm sideways clearance to the edge of the fingerboard.

    4. The sound post should be close to a soundpost's width below the centre of the bridge foot and a soundpost's width across towards the g side FF hole

    So how does it all shape up on the above counts?
  8. :confused: Just wondering, Matthew, is the latter half of your statement about where the SP should be?

    I mean, those are the general parameters of where it can be located laterally.

    I've always heard the "classic" SP position was close to one sound post's width below the center of the bridge foot. Adjusting it out toward the g side FF hole is one of those places one can try if the tone is in need of more bass volume on the E and A strings, but are you saying that is the standard position?
  9. sean p

    sean p

    Mar 7, 2002
    eugene, oregon
    another possible reason for the improved sound could be the position of the bass side bridge foot relative to the bass bar. if the foot is more advantageously positioned in this respect (this probably means more directly over the bass bar) that could help sound too. i found that when i had a new bridge cut for my kay last year, one that was much wider between the feet so that it could be centered on the top/table and have the bass foot directly over the center of the bass bar, the sound improved dramatically. of course, we didn't move the soundpost, so the relationship between that and the treble side bridge foot was altered too. ah, the mystery!

    my .02, you know it sounds and feels better. you even said perfect! if it ain't broke...

  10. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    i'm saying usually it is close to there
  11. Gearhead43


    Nov 25, 2007
    Yep. Generally, usually, most of the time, not all of the time. :D