Mandolin.org.uk
Mandolin Doctor
Where does the bridge go?
Dave Hynds
Hello, Barry has asked me to write a few lines periodically, about general maintenance and problem solving, that may be of assistance to mandolin players old or new. This knowledge is based on my experience as a player, and as a restorer of well over 100 mandolins over the last 3 years, though I am happy to admit that there is still a lot I don’t know….. ‘learning all the time’, as they say.
Where does the bridge go???
I thought I’d start with a question that I have been asked several times, and on the evidence of the mandolins that I have worked on, is definitely not universally known! Where does the bridge go??? The attached photo illustrates the problem quite well. On this mandolin, (soon to be restored) the bridge is not only glued on, but way too far back. I suspect this was done to lower the action to make it more playable, but it must have been fearfully out of tune.
The mandolin is a ‘floating bridge’ instrument, in other words, the bridge is not fixed, and should not be. The scale length of mandolins, is usually somewhere between 325 and 355mm, with the old Italian bowls being shorter and the modern bluegrass instruments longer. The exact scale length is calculated by doubling the distance between the nut and 12th fret. This is where, in theory, the bridge should go!
I say in theory, because there is another major consideration. Because the strings have thickness, which tends to inhibit their ability to vibrate, the actual length required, for a string to vibrate at the exact frequency required to produce a perfect note, is a little longer than the theoretical length. Unfortunately, the thicker the string, the longer it needs. You can get fairly close to concert with a straight bridge, so that the open notes are close on an electronic tuner, and on the harmonic at fret 12. The slight inconsistencies will not be too evident except to someone with a very sensitive ear, or until you play further up the fingerboard.
All tuning is a compromise, and it is for the individual player to decide where the compromise should be. Double the distance between the nut and fret 12 plus 1mm is a good place to start, ignoring for the moment the playing action, which tends to stretch the strings slightly, and the kind of strings you want to play with. Once you find the slightly false notes annoying, or you want to go further up the fretboard, then we must look at compensated bridges…. which I guess would make a good second topic in a month or so.
All the best for now, any comments or questions are welcome,
regards Dave Hynds
Tip by Dave Hynds, June 2007
