Svenska fioler med resonanssträngar

If you construct a violin with a removable fingerboard (which is a feature on some historical double-deckers) the neck of the instrument will be weaker. Unless you compensate this in some way the string tension will pull the neck upwards and damage the instrument. On both my double-deckers I have made the neck thicker (in vertical direction) to make it stronger and I have also reduced the string length and the angle of the neck. A somewhat thicker neck will not affect playability, especially if the neck is not wider than on a standard violin. Shorter string length is traditional on the double-deckers and a reduced angle is not uncommon either but reduction of string tension will make the sound less loud and smoother. I don't know how to calculate features of wooden constructions and how much an extra millimeter of neck thickness will improve the strength but I have tried to calculate how much the reduction of string tension different neck angles and string length will lead to.

The pressure T on the bridge is calculated by this formula:

and these are the variables:

note that the Swedish letter ö is the distance from the plane formed by the upper edge of the ribs (or the lower edge of the violin top) and the upper edge of the nut.

If you use the following measures for a standard violin, it is possible to plot the pressure on the bridge as a multiple of the pressure on a standard violin on one axis, string length on one axis and bridge height on the third.

1% change in string length will affect the pressure more than 1% change in bridge height.

Copyright 2009-2020 Jon Magnusson