Mandolins have removable bridges. If the bridge is slightly out of place it will cause strings to be out of tune as you work up the neck. Even if your base note is perfectly in tune, as you work up the neck the notes will be more and more out of tune and sound terrible.
This is such an easy problem to fix that there is no reason for any mandolin to be out of tune. Even a very inexpensive mandolin will sound fine if the bridge is placed in tune with the harmonics of the 12th fret.
Learn Mandolin Harmonics
On a mandolin, a half-string harmonic is sounded by placing a finger lightly on the string over the 12th fret and plucking. What this does is forces the string to vibrate exactly in half, which makes a note an octave above the tuning of the string. You can do it on any of the strings on the mandolin.
After plucking the harmonic and hearing it ring, press your finger down on the same 12th fret and you should get exactly the same note. If the fretted note is sharp, then you will need to lengthen the string by moving the bridge toward the tailpiece. If it sounds flat, you do the opposite: shorten the string by moving the bridge towards the fret board
Proper Tuning is Important
It is critical that all strings on the mandolin be in tune, both as open notes, and on every fret played up the neck. Otherwise your playing is going to sound rough and bad. You may even be asked to leave the jam! The players in my local bluegrass jam group say, “Tuning is not optional!”
Worse than that, though, if you are not in tune, it’s going to sound off all the time when you play. You won’t enjoy it. You’ll never practice, and you’ll never improve. That’s a bad road to go down.
How To Tune a Mandolin
A mandolin has eight strings in four pairs with the following notes: GG DD AA EE. If you have a good ear you can tune them by feel to other players, a pitch pipe, piano or tuning fork. Electronic tuners are so inexpensive, and work so fantastically, that most players use them these days to stay in perfect tune.
New electronic tuners are coming out all the time, so keep your eye out for innovations. My current favorite is an elegant and space-age-looking tuner called a Snark. This tuner is so sensitive that it can actually pick up the harmonics from most of my strings.
The Mandolin Bridge
Mandolins have moveable and/or removable bridges. This is a great thing if you know how to move it to get in tune with the harmonics. It’s a terrible thing if it has been placed wrong, or slightly knocked out of place.
Most tuning advice for the mandolin will tell you to either not remove all strings when changing strings (so as not to move the bridge) or to replace the bridge carefully on the markings that the old bridge placement left on the face of the instrument. Again, this might be good advice if the bridge was previously placed impeccably, but not so great for every other scenario. It’s better to learn to manage the bridge.
Most mandolin bridges have little wheels to help you adjust the height of the strings. This is also a critical adjustment, as you will want your strings to be as low and close to the frets as possible without buzzing.
How to Restring A Mandolin and Adjust the Bridge
I always take all strings off my mandolin when restringing, and give it a good cleaning. I use Martin Professional Guitar Polish to clean and shine the instrument.
I like my action nice and tight so I lower my bridge each time I change strings. What I do next is only put four strings (one each: G D A E) back on the instrument so I can test and adjust both the harmonics and bridge height without having the pressure of all eight strings.
I like to wrap my strings on the pegs in an even coil (not crisscrossing over) with at least 3 wraps per string. The high E can have four or more wraps. I bring the strings up to a moderate tension (not anywhere near pitch) and then adjust the height of the bridge. Make sure you have your bridge back on correctly with the bigger groves on the upper side of the mandolin where the thicker strings are. Place the bridge as close to its former position as possible
You should never try to adjust bridge height with strings fully tuned as the pressure will damage the screw-wheel mechanism.
I pluck each string hard and bring the bridge height up to the point where the strings just lose their rattle. The side of the bridge with the A and E strings will usually be lower than the side holding the thicker strings.
Adjust Mandolin Bridge Placement
Now that I have the height of the bridge right, I bring my four strings up to pressure and get them exactly in tune. This usually takes a few adjustments as tightening each string will slightly change the pressure of the other strings.
Now, sound the harmonics on the 12th fret, and then play the note. Adjust the bridge placement accordingly. (Note that if the bridge is seriously out of placement you may need to loosen the strings to move it.)
- If the fretted note is sharp (in comparison to the harmonic) lengthen the string by moving the bridge toward the tailpiece.
- If the fretted note is flat (in comparison to the harmonic) shorten the string by moving the bridge towards the fret board.
Adjust for all four strings several times. Each time you adjust and move the bridge you will need to bring all four strings back into tune again. You will probably need slight adjustments back and forth to get your high E and Low G sounding perfectly. I am always amazed at the difference a tiny little movement will make. This is why I think it is critical for all mandolin players to know how to adjust the bridge through harmonics. A slight bump on the bridge could have dramatic consequences to an instrument’s sound.
When you have it perfect, play a few songs just to see how wonderful it sounds. Play really loud to make sure you are not getting any buzzing from your bridge height. If you are still not completely happy, go through the adjustments again.
Finish Stringing
After you have your four strings in perfect harmonic balance, go ahead and add their matching doubles. Check the harmonics and bridge placement again. Everything will probably be perfect and your mandolin will be in tune up the neck and down.
Connie Delaney - Connie Delaney writes from Salmon, Idaho where she is a web designer, occasional funny girl, and Dances of Universal Peace leader.
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