Non-Adjustable Bridge Adjustment?

[Wynder]

Greetings, folks!

After 15 years of symphonic percussion, I bought my first fretted instrument last week in an attempt to expand my horizons and love of celtic music. #I picked up a Trinity College Octave Mandolin which I lvoe dearly, but I seem to be having a small issue and I'm not sure why, due largely to my inexperience with the instrument...

Playing chords with my G string (D chord for instances), if I press too hard on the string, it pitches audibly sharp... enough to push the chord out of tune. #In testing, I held down the G string at the second fret and plucked the string and pulsed the string into the fret -- with that I was able to bend the note to some extend with each pulse.

Using my limited reasoning ability, I've come up with two theories:

1) Low quality strings or they just haven't been fully 'broken in' yet. #Or, more likely:

2) The bridge is a bit high for that string and the notch seat for that string may need to be shaved down.

Hopefully I'm wrong on the second account and it's something a bit more simple to solve... #Any suggestions?

Rob

http://devnull.dtcc.edu/mando.jpg

[danb]

Hmm, a number of possibilities, though all are relatively easily addressed. If the frets are jumbo ones and the tension is low, you might be bending the string slightly by pressing really hard. If the nut is too high, or the bridge saddle not correctly compensated, you could also be going sharp there.

Try to match the harmonic on the 12th fret with the fretted note, or if you have a tuner, just verify that the open string and the octave at the 12 are both in tune. If they aren't.. move the bridge a bit (close to the soundhole goes sharper, away goes flatter).

[Wynder]

Thanks for the advice...

When I do try to match the harmonic, depending on how hard I push down on the string, it goes sharp -- just on that single string, though.

One catch though -- my bridge isn't adjustable. Is there a way around it (i.e. shaving down notch in the bridge for the G-String?) or is it something I should get a luthier to take a look at? (I'll try the string bending when I get home today.)

Rob

[John Flynn]

On any mando a string will go sharp to some degree if you press too hard, especially if you are pressing too far behind the fret. The answer: Don't press too hard and only press right behind the fret. Also, I am not even sure it is possible or even desireable for a mando to be in absolutely perfect tune across the fretboard. See some of the recent threads on equal tempering versus well tempering. I would see a good luthier and ask if the instrument needs a setup. If it does, get one. A good setup addresses the issues you raise and a lot more more and it is the cheapest instrument upgrade you can buy. It should cost you less that $100 and it is well worth it, no matter what the price of your mando.

[sunburst]

Pressing hard will pull the string sharp. It stretches the string as you push it down into the space between the frets. The lower the tension on the string and the longer the didtance between the frets, the more you can bend the note sharp.
The solution? Practice! http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

[Wynder]

Pressing hard will pull the string sharp.

This makes me feel a bit better -- it is most noticable between the larger frets. I've tried to use a lighter touch, but my inexperience with the instruments generally yeilds a nice buzzing sound. ;)

The solution? Practice!

One week down, 45-90 minutes a day -- already have calouses on my index and middle finger. ;p