The position of the bridge should be such as to affect the whole violin equally, and not to favor one tone more than another. The centre of the bridge should be always directly over the centre line of the top. Whether it should stand slightly backwards or forwards of, or directly on a line drawn across the top from the inner notches of the f holes, will depend upon the character of the instrument, and can only be determined experimentally. It should incline toward the tail–piece in order to better withstand the forward pull of the strings in tuning.
The construction of the bridge has great influence upon the tone. Thinness of the centre of the bridge tends to make prominent any nasal quality or shrillness latent in the instrument. A proper solidity conveys sweetness and compactness, but too great thickness muffles the tone.
High–built violins mostly require low bridges, and such should be particularly thick at the edges where the strings rest.
The bridge should be perfectly flat on the side toward the tail–piece. It may be slightly convex on the other side.
The material of which the bridge is made should be invariably maple. That which is known as the silver–gray maple is preferable to the brown or yellow, as having a more close and elastic grain.
The incisions in the sides of the bridge should extend each one third of the distance toward the centre. The French model of Aubert of Mirecourt, though open to some objections in special cases, is one of the best. These bridges are made of excellent wood, and are thick and strong.
The top of the bridge should be thick. Properly constructed, a bridge may be made quite heavy, and so made it will always convey a rounder and fuller volume of tone. The distance measured along the top, between the G and the E strings, should be 1–10/32 inches. The G string should be 8/32 of an inch above the finger–board at its larger extremity; the E string, 5/32 of an inch. The average height of the feet of the bridge should be about 3/16 of an inch. The thickness at the base, a scant 5/32 of an inch; at the top, a full 1/16 of an inch. The feet should be 7/16 of an inch long.
THE SOUND–POST.
In general, the sound–post should stand from 1/8 to 1/4 of an inch to the rear of the right foot of the bridge. Its outer edge should be in line with the outer edge of the foot. From this position its upper or lower end, or both, may be moved with advantage to secure certain qualities of tone. It should in all cases fit the curves of the top and back absolutely. Moving the lower end toward the centre favors the lower strings. If the lower strings are weak and the upper at all sharp or hard in tone, then a very loose post should be used. If the reverse is the case, a long and tightly fitting sound–post is required. Moving the upper end outward will help all the strings, if the tone before was hard and shrill; but if the upper strings happen to be dull and heavy, then the post should stand a little inside the line of the foot of the bridge, and a little further back. The sound–post should be made of fine–grained soft spruce. The grain should cross that of the top, as this will prevent the marring of the inner surface of the top in putting the post in and adjusting it.