tuning/bridge position

Discussion in 'Setup & Repair [DB]' started by kip, Oct 14, 2002.

  1. kip


    Sep 11, 2002
    Sausalito, Ca
    When playing an open string, I notice that as the note decays it goes sharp. This is most noticeable on the G and D. Also, the octave harmonic on these stings is sharp compared to the open note. The bridge feet visually appear to be centered to the notch, but I haven't measured. Do I lengthen the string (move the bridge down) to get consistent pitch? Is this something I can safely do at home? Thanks.
  2. That is unusual. Usually as a note decays it goes flatter. That is because as the amplitude of vibration lessens, the string slackens slightly.

    The position of the bridge doesn't have anything to do with the phenomena you're describing. The octave harmonic should always be just that regardless of bridge position.

    If you are convinced that you are really hearing what you think you are hearing, I would look at the strings. As strings stretch, they sometimes do so unevenly, leaving slight inconsistencies in guage and mass and causing strange behavior like you describe.
  3. kip


    Sep 11, 2002
    Sausalito, Ca
    I also checked with a decent chromatic tuner and the VU meter does confirm my ear. You are probably right about the strings, this is a new bass to me but I don't know the history on the strings or how hard they were streched when installes.
  4. Bridge position in relation to the octave is really only critical on fretted instruments.
  5. Matthew Tucker

    Matthew Tucker Gold Supporting Member Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    The position of harmonic and the note underneath it is interesting. In another thread someone said that D lay right under the D harmonic on the G string, whereas I find that the note directly under the harmonic (ie I don't move my finger) is sharp. I put this down to increased string tension when pressing down the string, and compensate a bit.

    I presume this is normal though?

    Kip also said that the octave harmonic is sharp compared to the open note (which I interpret as meaning open string). I haven't noticed this.

    But someone replied that this is normal. Why?
  6. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY

    Another reason not to play 'em. :)
  7. Alex Scott

    Alex Scott

    May 8, 2002
    Austin, TX
    Sounds like some weird stuff, maybe you should replace the strings if you don't know how old they are. Also, how is your set-up? If you want strings to have more in-tune harmonics, you might want to use lighter-gauge strings that are set up pretty close to the fingerboard, and a smaller amount of relief in the board might help, if that is real extreme.

    Hold your string down like on g# and then at the end of the fingerboard. Notice this scoop and compare with other basses that you like, if any.

    I try to replace the strings when the harmonics sound off, compared to the open string. If that isn't better, check your set-up. Don't borrow your friend's old strings, they are dead.

    By nature, they won't be perfect. It has to do with your string having mass. Ask some physics-minded bassist to explain. Also, your tuner probably won't account for the actual harmonic series, it probably uses that tuning system they use for piano. Your fifth will be too wide, even if it was perfect., the third will sound flat, etc. To understand this check out a book by Paul HIndemith, The Craft of Musical Composition, this explains the concept very clearly.

    Good luck fighting the compromises of our tuning system and the imperfect string.

    Just play what sounds right and try not to mess up your head.
  8. kip


    Sep 11, 2002
    Sausalito, Ca
    Thanks everyone for the help. The G string does modulate up and down during the duration of decay and goes sharp just before it dies out. Will try new strings. Neck bow is not extreme. After years of agony with EB and Conn Stobe setting bridge and neck everytime I change strings, it is refreshing to find out all I have to do is work on intonation. No sweat.

  9. Sam Sherry

    Sam Sherry Inadvertent Microtonalist Supporting Member

    Sep 26, 2001
    Portland, ME
    Euphonic Audio "Player"
    If your experience is anything like mine, you'll rue those words sometime, Kip. Go get 'em!
  10. kip


    Sep 11, 2002
    Sausalito, Ca
    My comments were not without sarcasm. It's a whole new world on DB and I have yet to learn to crawl, let alone
    Thanks for the encouragement.