Violin Parts Guide
Violin parts not visible: Sound Post and Bass bar.
Welcome to violin anatonomy 101! One of these days I'm going to pull a violin apart and get a shot of the inside for you. Sadly, you are going to have to make do with learning about the outside first. Not an exhaustive tour, but hey, not a bad start either :-).
Click on the labels on the picture to get more detail on that violin part.
The scroll is the only part that has no effect on the sound of the instrument, serving a purely aesthetic purpose. It does allow room for considerable freedom of artistic licence, for example being shaped like a lions head instead of a scroll.
The pegs are used to tune the instrument, allowing the strings to be tightened to raise the pitch or loosened to lower the pitch of a string. While they need to move to tune the instrument, they also need to stay put once correctly tuned. (and student instruments that wont stay tuned are probably second only to students who don't practice as a source of frustration for music teachers!) To achieve this, the pegs and the holes they fit into are tapered. Pushing the pegs inward will tighten them up, holding them in place. You can also get peg drops to reduce slippage or peg soap to reduce friction if the pegs keep getting stuck. (graphite will also do the trick)
Pegs are traditionally constructed of ebony, rosewood or boxwood. Variation in temperature and humidity can cause problems as the peg box and pegs are made of different woods, and so expand and contract at different rates. Wood also expands and contracts at different rates along the direction of the grain compared to across the grain. Thus both the round hole in the peg box and the round peg can change shape with weather fluctuations. Modern pegs made of carbon fiber are one attempt to address this.
The winding of the strings on the pegs goes from the inside of the peg box to the edge, but not so as to touch the walls of the peg box.
The neck is set at a slight angle to the body so that the strings sit at a uniform distance above the fingerboard along their length. You will usually find the neck is not varnished.
The fingerboard is traditionally made of ebony. It has a slight dip along the length of the fingerboard to allow the strings to vibrate freely without touching the fingerboard. (The strings will experience the greatest displacement from resting position in the middle of the string, and will buzz if they hit the fingerboard). It is curved in the other direction to allow a single string to be played at a time.
Because the end of the fingerboard protrudes past the neck, it has its own vibrational modes which have an effect on the sound of an instrument.
Purfling is a strip of laminated (3 layers in this case) wood inlaid to a depth of about half the thickness of the wood, just inside the edge of the body of the instrument. Purfling provides resistance to wear from use, and resistance to cracks at the edges. It also has an aesthetic function, highlighting the shape of instrument. Very cheap instruments can have a painted, rather than inlaid purfling.
The bits that vibrate and start the process of generating the sound! Strings are most commonly made of a steel or perlon core (perlon is a substance similar to nylon) wrapped in a metal such as aluminium or silver. Originally they were made of gut, which has the disadvantage of being more temperamental in varying humidity and temperature, but has the advantage of rich, complex overtones. Steel core strings do not generally have the same warmth as gut strings but are cheaper and more stable. The arrival of perlon core strings in the 1970’s provided a stability similar to steel core, but a warm tone similar to gut strings. They are generally more expensive than steel core, and a little thicker, but make a noticeable difference on a well-built instrument.
F-HOLE (or sound hole)
The f-holes, or sound holes, allow transmission of the vibration of the air inside the instrument to the outside. They have a significant impact on the sound of the instrument. The size of the holes affects what frequencies are best transmitted, and the flexibility of the front plate. Sound will project most strongly in the direction the f-holes face when playing the instrument.
The bridge on a violin holds the strings at the correct height above the fingerboard (too high makes it hard to press the strings down, and too low makes them vibrate on the fingerboard), and keeps them sufficiently separated to allow individual strings to be played. It is responsible for transmitting vibrations from the strings to the body of the instrument and consequently has a large impact on the sound and playability of the instrument. Along with positioning the sound post, getting a bridge properly fitted to an instrument is part of the setup any instrument worth playing should have.
The chin rest was introduced around 1820 by the German composer and violin virtuoso Louis Spohr to make the instrument easier to support. Along with the shoulder rest, it allows the instrument to be supported between the chin and shoulder alone, leaving the left hand completely free for playing the instrument, and in particuar making shifting much easier. Chin rests either clamp onto the instrument just to the left of the end pin (viewed looking at the end pin), or above and below the end pin itself. This is the better option as there is more structural reinforcing at that point, being positioned over the end block (The end block is the piece of wood the end pin is fitted in to.)
Tailpieces can be found made of a variety of materials including ebony or rosewood, boxwood, or metal. The tailpiece is not fixed in place but held by the tension of the strings and the tailgut. It affects the sound of the instrument in a couple of ways. First, along with any add on fine tuners, the position of the tailpiece affects the length of the string from the bridge to the end of the strings. This has a subtle effect on the overtones generated by the strings. Fine tuners integrated into the tailpiece allow the strings to be set at the proper distance between the bridge and end of the string.
Because it is free to vibrate, the tailpiece has vibrational modes of its own, and absorbs certain frequencies of vibration depending on its mass and distance to the bridge. Add on fine tuners affect this (the extra mass tends to dampen vibrations), though integrated fine tuners have less of an effect, as they tend to have less mass.
The sound post is a 6mm diameter cylindrical piece of spruce that sits inside the instrument between the front and back plates, near the foot of the bridge nearest the E string. It is not glued in, but shaped to the curvature of the instrument and held in place by the innate tensions in the instrument. Like the bridge, it has a large influence on the sound of the violin, and part of a professional set up of a violin will involve fine tuning the position of the sound post.
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The bass bar is a strip of spruce that runs most of the length of the instrument, passing under the foot of the bridge nearest the G string.(you can just see it through the f-hole nearest the G string). It causes a larger area of the front plate to be vibrated by the foot of the bridge nearest the G string than would occur without it, and particularly influences the lower notes (<600Hz). It also provides structural reinforcement against the pressure of the strings.