View Full Version : Bridge Set Up

Hal Loflin
May-08-2004, 8:37am
I restrung my mandolin and had marked where the bridge was before restringing. After replacement I now am getting a loud harmonic ring on the 12th fret/4th string (G string) when I let off on a chop with my little finger )playing C or G chords). I did not have this before restringing and I am thinking that I need to move the bridge one way or the other. Help...What is the proper placement for the bridge from the twelth fret and what points do I measure from (the nut to what point of the bridge with the 12th fret being in the middle)?

John Flynn
May-08-2004, 9:21am
The issue of where the bridge sits has nothing to do with getting a harmonic ring like that. Where the bridge sits has to do with intonation. This is often tested by ringing a harmonic over the 12th fret and seeing if it is the same tone as the fretted 12th fret. I would set the bridge acoustically with an accurate tuning meter. There are luthier's tools you can use to physically measure the distance, but I wouldn't do it with a common ruler. It's the acoustics that count anyway.

Getting an unwanted harmonic ring when you are playing is a whole other problem, however. It can have to with your technique in the way you let off the chop chord and it can also have to do with the strings themselves. Sometimes new strings, especially some models, like the EXPs, will have unwanted harmonics for some time after you put them on. Question: Why do you say that the harmonic is ringing at the 12th fret? Your fingers would not normally be anywhere near the 12th fret for a C or G chop, so I am confused about that.

May-10-2004, 7:49am
Are you sure the ringing you hear is not coming from the strings between the bridge and the tail piece? If that's where the problem is, there are any number of ways to mute the strings there...

May-10-2004, 7:54am
A handy mnemonic for me is "the 3 F's"

If the Fretted note is Flat, move the bridge Forward...

Willie Poole
May-12-2004, 8:07am
I had this problem on one mandolin and I checked the seating of the bridge and it wasn`t flush all the way across the top of the mandolin and I guess it let the top vibrate a little against the bottom of the bridge, I just re-seated it and it stopped. Check it real close ...Once you find the right place don`t remove all of the strings when replacing them, do them one at a time...Good luck.... Willie