correct placement of bridge?

Discussion in 'Setup & Repair [DB]' started by Peter Kaae, Apr 11, 2005.

  1. Peter Kaae

    Peter Kaae

    Oct 10, 2004
    I´ve owned a Strunal 5/5D for a year, and have now discovered a problem, I think.
    Acording to the Strunal website, the length of string from nut to bridge should be 1050 mm, but when my bridge is located in center of the "F" key mark, my stringlength is 1080! When I locate my bridge so the stringlength is 1050 mm, the bass sound better, but is far from the F-key marks. How should I locate the bridge? What is the correct placement of the bridge regarding to stringlength and F-key marks?
  2. Typically the bridge feet are centered on a line connecting the interior notches in the F holes, but the discrepancy you observe, 3 cm, regarding string length is considerable. Check the angle of your bridge to the body to make sure it is not leaning excessively toward the tailpiece if you haven't already. Make sure you aren't including the nut in your measurements.

    When you moved the bridge to comply with the published string length did you leave the soundpost where is was originally? You know that changing the distance north to south from the bridge foot to the post is a tweaking operation. I see no harm moving the bridge or the post as long as you fit the bidge and post properly and track the way the bass sounds as you go. 3 cm is a huge amount of adjustment, and a discrepancy like this would concern me as well. I'd be tempted to think that the f holes are possibly too far south. Most 3/4 basses commonly have 105 cm (1050mm) string lengths. Usually 107cm. is what you see on the 7/8 sizes, so 108 is just plain odd.

    If there is a picture of a Strunal like yours on their web site, how does it compare with your bass as to bridge placement, f hole location, etc? Maybe someone on the forum with a strunal can compare with what you have found.
  3. Peter Kaae

    Peter Kaae

    Oct 10, 2004
    I have emailed Strunal , to hear their view on this.
  4. Samie


    Dec 13, 2000
    Madrid, Spain
    I have had the same question on other DB.

    I have concluded that if you center the bridge on the top sign of the F, and if the bridge is slanted correctly, the strings endup right on top of the lower F string sign.

    Maybe you should center on the bottom sign of the F only if you dont slant the bridge. I can't find any other use to having 2 different f sign. :eyebrow:
  5. Peter Kaae

    Peter Kaae

    Oct 10, 2004
    I received answer from Strunal (very very friendly people indeed) and, they say that the actual stringlength of the model 5/5 is 106-107 (allmost 43") and if the stringaction is very high (as on my bass) if could be 108. So I will place the bridge "correctly" , and live with it.
    The bridge was made by a great luthier, and I will place it exactly where he did.
  6. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Look at the bridge on the bass on the left of this page in the New Standard Basses ad. Notice the bridge is not slanted and it is aligned so the bridge would center straddle a line drawn to connect the two inner notches in the ff holes.

    This is the correct placement. Luthiers may wiggle up or down a bit to tweak, but this is the standard placement.

    The bridge should not slant at all. The bottom edge of the bridge should be perpendicular to the plane created by seam of the table and ribs.
  7. Samie


    Dec 13, 2000
    Madrid, Spain

    Check the side view of the bridge. After your are dont sanding off the top, the strings will NOT be at the center of the bridge. Now days bridges are made this way to minimize slanting upwards by the string presure.

    If center the feet of a non wedged bridge with the inner f sign, the strings will be right above the inner f sign at the top of the bridge.

    If you center the feet of a slanted wedged bridge with the outer f sign, the strings will be right above the inner f sign also.

    If you center the feet of a slanted wedged bridge with the inner f sign, the strings are going to be 2 to 3 millimiters behind the inner f sign. Making your scale larger

    It makes sense to me :ninja:, then of course I am no luthier. However my bass sound best when the strings line up with the inner f hole at the bridge, not behind. These also makes it easier to play first position notes.
  8. Matthew Tucker

    Matthew Tucker Gold Supporting Member Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    my brain hurts ...
  9. Samie, I'm guessing English is not your first language (but yours is still a whole lot better than my Spanish!).

    Would it be fair to summarize what you're saying as: If you centre the bridge feet on the line between the f-hole points, the strings won't be directly above this line because the bridge is not symmetrical?

    I hope you don't think I'm being patronising, I just want to make sure I understand what you're saying.
  10. Samie


    Dec 13, 2000
    Madrid, Spain

    Yes, that is what I am saying.

    There are 2 f-hole points, one in the inner part of the F-hole, and one on the outer part of the f-hole

    If you center a non symetrical bridge feet on the outer f-hole points, your strings will be lined up exactly above the inner f-hole. This is the way it should be

    I came to this conclusion on my own, but check out this pic I found by accident. It was not that off after all. The feet are centered with the outer f-hole point.


    yeah, my spelling is terrible. Is not the english, i am just a lazy bum. In spanish people cant understand me either so dont worry.

    YOu got it right.
  11. Samie


    Dec 13, 2000
    Madrid, Spain
    They say a picture is worth a 1000 words. Does this explain my theory?

    Attached Files:

  12. Yeah, it does, man. But there are huge differences in the positioning of the inner and outer notches in different f-hole shapes. If I, for example, positioned my bridge legs in the center of OUTER notches, it would misplace my bridge about 3 cm. Also my string length would be about
    3 cm shorter.
    So, I still think the most common way is that a straight line drawn from the center of the foot meets the inner notch of the f-hole.

  13. Samie


    Dec 13, 2000
    Madrid, Spain
    3 cm? or 3 mm? 30 cm is 30mm, are you sure about the diff? Chech the attached pic, the diff is usually 3 to 5 mm.

    It might be more common, but I found that on my bass it sounds better and is easier to play when the string side of the bridge is right above the inner notch.
  14. It´s 3 cm, Samie. I´m metric.
    I seen yo pic, man, but the inner and outer notches in MY f-holes are 3 cm away from each other. I really do not think there is any common rule.
    I´ll post a pic when I get home.

  15. prelims222


    Sep 20, 2004
    Southeast US
    Those 'f-hole nicks' are called mensur marks, and indicate the (ta da!) mensur (string length) for instrument. On the bass, their placement tends to vary some, you don't find this much on the other string instruments, especially violin, where the numbers are basically set in stone, and the tolerances are in fractions of a milimeter, not inch.

    Don't go moving the bridge around too much, because in addition to shortening your string length (desired effect) you are also changing the instrument as a whole. Those bridge feet contact the top in a spot that has a lot of impact on sound, structural integrity, and response. Think about it: when you move them, you are changing the point at which the top vibrates around; you are also changing the point at which there is a lot of downward pressure going on the top with the opposing bass bar and sound-post.

    For some out there, it means you are changing the divisions of the vibration air columns within the bass, which can also affect the sound.

    I'msure someone with experience can chime in with greater knowledge about exceptions to these things, as well as other issues with it that I haven't encountered.
  16. There, see what I mean.
    These are my buenas notches.

  17. We just purchased a Roma carved- which was shipped with the bridge down as expected. After reading instructions on this site we placed the bridge- we had a school-owned Kay here for visual reference. Now I think I understand that top to bottom the strings touching the bridge should line up with a line drawn between the inner f- hole notches.The Kay bridge was also centered left to right between the f holes.

    The sound post remained in place after shipping. In order to line up the strings with the fingerboard the bridge placement is to the right of center when facing the bass, by a good bit. This is also where the feet fit snugly and the sound post is about a sound post width toward the tailpiece just below the bridge foot on the right. When running your hand across the bass top you can just feel the sound post.

    So questions: is the left to right placement as critical as the top to bottom, and does this placement sound acceptable?

    If this left to right placement is not acceptable- what might be the cause and solution?

    Should you be able to feel the sound post from the top at all?

    Thanks in advance for your feedback.
  18. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    I would strongly suggest having a local luthier take a look at the bass. I would be concerned that the bridge doesn't line up on-center with the ffs L to R. That can suggest a poorly aligned neck. Not good. Also, the other foot should rest on the bass bar.
  19. Samie


    Dec 13, 2000
    Madrid, Spain
    My cheap bass was not neck-aligned perfectly either. If you find where the feet feel like they are meant to go at, try it.

    If it does sound right, check with other basses or luthiers.
  20. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    This says that modern bridges are cut so that it would be correct to center the bridge feet on the outer f-hole nicks so that the strings lie over the inner f-hole nicks. I'm not a luthier but I think this is completely wrong.

    I hope one of the luthiers here will chime in.