Violin Forum/Message Board

[James Sanford]

I am having a lot of trouble determining the correct bridge location when setting up/checking a fiddle.

I am used to dealing with fretted instruments where the string length is +- twice the distance from edge of nut to mid-12th fret. IE, if the distance from nut to 12th fret is 155mm then the bridge should be located 155mm from the 12th fret. Of course this is adjusted for string compensation.

The fiddle I have on my bench measures out as follows:

267mm end of finger board.
328 mm string length when sitting bridge at front notch in f-hole (notch closest to tail piece).
164mm calculated mid point of string length (typical location of 12th fret)
172mm actual octave point of string.

My observation is that the second octave seems to be in tune with the first but the string length for the second octave is 156mm instead of
length of 172mm 1st octave.

This is very confusing to me when trying to set the string length so that finger positions are consistent from one violin to another.

I assume that I could locate the bridge any where I wanted to...but this would change the various lengths of the finger positions.

Where am I missing the boat?

[Chet Bishop]

Physics and wave frequency principles do not change. If your real string length, from the leading edge of the nut to the contact point at the bridge (not the bottom of the bridge) is really 328 mm, then, yes, of course the harmonic for the octave should be at precisely 164mm.

I don't know what you are doing differently, but you have stated the facts correctly: an octave means twice the frequency = half the string length.

The balance between the vibrating string length and the "afterlength" (distance between bridge and tailpiece saddle (the fret under the strings on the tailpiece)) is another matter. People say that it should be a 6:1 ratio...so, if the actual vibrating string length was 330mm, say, then the afterlength should ideally be 55mm. There is some discussion about the importance of this balance, but the way to achieve it is to lengthen or shorten the tailgut, as required.

In general (yes, there are exceptions) the bridge is centered laterally and longitudinally between the inner nicks on the f-holes. You are not locked in on this: if it simply plays best a few millimeters north of that line, then so be it. that is where it will have to go. But I would be really curious about soundpost position, etc., before deciding that the bridge needed to be somewhere other than that location.

Don't know if this helps. I wish one of the experts would chime in. I waited, hoping they would do so earlier. Evidently they are all busy...

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Chet Bishop
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[L P Reedy]

Since you don't have frets, the "12th fret position" is rather unimportant. Some factors that would influence it include string type, fingerboard clearance at both ends and string condition (new, dirty, corroded, worn). I don't think players ever measure to find where to play the octave. If your 172 mm (measured from the nut) is pushed down to the board, it sounds about right. By the way, guitars don't actually have the 12th fret exactly halfway between the nut and the bridge.

And yes, string length is one of the more important measurements and 328 mm is good.

[James Sanford]

[Mat Roop]

Some info for what it is worth....
1- Thomastik advertise the correct string length (mensur) for their strings for a 4/4 violin as 325 mm (12.79")
2- depending on the violin, there are 3 basic ways to set up the bridge position... a) as the maker made it ie... align the bridge with the inner nicks or... b) correct string length, and.... c) proportional rule of 5ths...divide the body stop distance by 3 and multiply that by 2 to get the neck stop distance.

Of course there are some violins that don't seem to work with either of the 3 methods, so that's where you start to experiment. What counts in the end is that you get the most that the violin can deliver.

Cheers, Mat

[Michael Darnton]

I guess the fascination with string length is a fiddle thing, perhaps because it's considered important for guitars. In the classical world, the proper placement of third position is much more important for the player, and that's achieved by maintaing the 3:2 relationship between bridge stop and neck length: usually 130mm from the end of the board to the edge of the top, next to the neck, and then 195mm down from that point to the center of the bridge.
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[Michael Darnton]

I should maybe amplify on the rules.

1/ Because it's less comfortable for the player to be working over the body, they're more tolerant of a neck that's long, or stop that's short, which moves the notes out into the free part of the neck.

2/ To get 195mm stop, it's OK to put the bridge wherever it needs to be with the inner nicks somewhere within the thickness of the bridge.

3/ If you can't do that, moving the bridge north of the nicks usually has less undesirable tonal effects than moving it south. This has the effect of loosening the strings a bit when they're tuned to the same pitch, and most instruments sound better with looser strings rather than tighter ones, manufacturers' design specs notwithstanding (if you want to do an interesting experiment, tune your violin down a half step and see what you think.)
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[James Sanford]