Problem with violin finger placement changes with each string?

Question

I have a violin student who recently purchased a violin from a music shop. It's not a professional grade violin, but it is still a nice student model. My student's intonation seemed to get worse after he got it, and I finally noticed something I've never seen before...

Although each string is in perfect tune with each other, he has to place his fingers higher on the fingerboard for every higher string. For example, the G string finger placement is normal. The D finger placement is a little more spread out (i.e. the third finger on the D string isn't in tune unless it's higher than the third finger on the G string). And then the A and E string finger placements have to be even more spread out to be in tune. I hope that makes sense.

Anyway, I use tape to let him know where to place his fingers, and after going through each string, the tape isn't straight across the fingerboard as it usually is, but is tilted at quite a noticeable angle.

Can anyone tell me what the problem is? It must be a problem with the violin, but I'm not sure what it is. And it sounds like such a strange problem. I've been teaching for years, and have never seen this problem before. Obviously, he needs to get it fixed because it is affecting his playing and intonation.

Answer 1

This problem has not obvious solutions. I recommend bringing it to a luthier to get it checked. There are so many possible causes, like bridge tilting, bridge perpendicularity, string tension.

Answer 2

I would try and work out the possible causes and then go through and try and eliminate them.

The note produced by a vibrating string depends on the length, tension and composition of the string.

Apart from fingers depressing the string, the way the length can vary from string to string is if either the nut or the bridge is at an angle. This should be a relatively easy visual check.

I can't think of a way that the tension could vary across the length of the string, but maybe that is possible.

In a well made string the composition should be uniform.

In any case, unless I could see something obviously wrong with either the bridge or the nut my first attempt at narrowing down the problem would be to replace the strings with a known set. Ideally the music shop should have sold the violin with a good set of strings, but you never know. If changing the strings doesn't fix the problem then I would take the violin back to the shop.

Answer 3

There will always be a slight difference in the position of the notes on each string due to the different thickness and tensions of the strings. On the violin this difference is close enough that is is usually not noticeable.

The action setup and position of the bridge will cause tuning problems if setup incorrectly, especially if the action is too high. High action causes more deflection of the string, creating a difference in the final location of the fingered note on the different thickness and mass of each string.

The height at the nut, the scoop of the fingerboard, the height of the strings at the end of the fingerboard and the position of the bridge all need to be adjusted to within certain measurements to function correctly.

At the nut the strings should be about a third of the diameter of the string above the fingerboard. The E string about a quarter millimeter high. On new stock violins the nut is usually set high.

The scoop of the neck should not be too deep. Depressing the string at the nut and end of the fingerboard, the G string scoop shouldn't be deeper than about one mm.

The Bridge placement may be approximated by measuring the neck from the nut to the body joint, or where the top ends at the neck, and dividing this measurement in half, and then multiplying that number by three (to get a 2:3 ratio) to get the distance from the top at the neck to the bridge foot.

For many violins this will be 13 Centimeters from nut to neck, divided by 2 to get 6.5, times 3 = 19.5 cm from neck joint to bridge foot.

-- do not rely on the F hole notches for bridge placement. Some student model violins do not set these correctly. --

Once the bridge is set, the string height should be measured at the G and E strings at the end of the fingerboard. A commonly recommended height is about 5.5 mm at the G string and 3 - 3.5 mm at the E string.

If all the measurements are in range and there is still intonation problems, replacing the strings with a different set might help, but more likely there is something physically wrong with the instrument.