Although the notches in the f-holes can be a good general suggestion for bridge placement, they aren't always the best location on every instrument.
Determining a more accurate and often better sounding placement is achieved by determining the MENSUR. The MENSUR is a ratio of neck length to partial body length to determine bridge location.
Use the following instructions to determine the MENSUR of a violin/viola:
1. Measurement 1:
Measure the distance from the end of the nut (closest to the fingerboard) to the edge of the violin top next to the neck.
2. Divide the total of Measurement 1 by two. (13 cm / 2=6.5 cm on most 4/4 violins)
3. Multiply that number by three. (6.5 cm x 3= 19.5 cm on most 4/4 violins)
4. The resulting measurement (from the edge by the neck, to the center of the bridge foot) is the proper location of the bridge for the violin/viola, thus a 2:3 ratio.
The MENSUR for the Cello the ratio is 7:10 and the Bass is 3:4.A couple of final important notes.
*When moving your bridge to a new location, your soundpost may also need to be adjusted. Make sure to bring the instrument in to see if your soundpost needs to be tweaked with your new bridge placement.
*If you have any markings on your fingerboard (like tapes for finger placement), these markings will also need to change as a result of a bridge shift and lengthening/shortening of the vibrating string length.
Although we strongly recommend having the size checked by a teacher and/or a member of our staff, we realize it isn't always feasible to bring the student to our store for sizing.