The Violin Family
In more modern orchestral works, the subdivision is often multiplied many times over, as you can have the situation where what the desks (that is the pairs of violins playing on each music stand) may be divided in the score, so that perhaps the first 2 desks play one part, the next 2 desks another part, the next 2 desks another part. Thus within just the first violin section there may be 3 or more separate lines of music being played. The same can happen in the 2nd violins, also in the viola's and sometimes in the cellos and basses. In very extreme cases you could have 12 or more lines of music going on within the string section, all at the same time. This process is called divisi. This happens when the composer is wanting very thick and complex chords. However most of the time, all members of particular section are playing the same music.
I've described the basic structure of other instruments, so here goes and let's have a go at trying to describe the violin. Remember first of all that the whole shebang is made of wood. The only metal part you might find on some violins is a single tuning screw for the top, E string. The rest of it comes from a tree. So when you listen to a performance by a string quartet, it really is tree music. Could that be whether the term string trio comes from? Sorry about that!
Imagine holding a violin in your lap longitudinally, with the 4 tuning pegs on the left. Going from left to right you have the scroll (just a decorative carved piece, and occasionally on cellos this decoration can be carved in the shape of a head, either human or animal), forwarding tuning pegs, a fingerboard made of a very hardwood such as ebony, so that the strings vibrating on top of it don't carve grooves to quickly (whether strings are pressed by the fingers onto the fingerboard, crews will eventually be created, and you have to take instruments for violin garage to have it serviced, i.e. have the fingerboard smoothed out). The fingerboard is glued on top of the rounded neck of the violin, a shoulders the ribs on each side, the belly on top and the back, both curved for strength and resonance, this bridge and inside the box structure signpost. That gives the idea that there are about 19 pieces to the violin, but in fact there are about 70 separate pieces of wood in most instruments, though designs vary slightly. The whole lot is glued together with fish glue, that smelly stuff that you melt in a pot if you've ever done old-fashioned woodwork. You would think that to make the thing strong it would be stuck together with some sort of high-strength epoxy resin, with the trouble is that once you got it together you could never take it apart. A skilled violin renovator can take a violin apart because the fish glue has limited strength, so it's quite possible to disassemble a violin, do necessary repairs and then glue it back together again.
I suppose I should correct one thing when I say that all violins are entirely made of wood. This isn't quite true. The violin that would be played in a Symphony Orchestra or in the string quartet, and in the majority of ceilidh bands and barn dance bands, would certainly be traditional wooden instruments. However there are such things as electric violins, which can be an aluminium or carbon fibre stick, without any sandbox, with some sort of chin rest at one end and tuning pegs, possibly geared like guitars, at the other end. Strings are stretched over a bridge in the traditional manner, but below that bridge or built internally to it a vibration sensors which are plugged into a power amplifier. Such instruments make no sound at all on their own, because there is no sound box, and all the sound is made via the PA system taking signals from vibration sensors, most usually Piso electric sensors of some sort. Beyond having the central stick with the right dimensions, and the right shaped neck the violins hand to slide along, it doesn't matter two hoots what shape the instrument is, so it gives great scope for artistic licence and you get some very trendy and sexy shaped sculptures made out of electric violins.
Of course, trendy violins like this are very popular in pop bands, but they often appear in the more upbeat barn dance bands and in jazz bands, although there is still a strong tradition to play a traditional wooden violin in a jazz band. The sound is, as you would think, considerably different. Many of them sound very harsh and raucous, and you have to pay an awful lot of money compared with the traditional violin, to get something that sounds good. That good sound is, however, quite different from the sound of traditional violin. This can be good or bad depending on what sort of musical playing. The cheaper electric violins are often sold as practice violins, so that the poor suffering parent doesn't have to listen to their child scraping away out of tune, at some horrible nursery tune. The child wears headphones that are plugged in to the violin, so they can hear themselves playing, but the amount of sound that comes directly from the strings is very small. This also has the advantage that there is often a separate input for a CD, so that the pupil can practice with backing tracks, which can make practising tremendous fun. There is an advantage for the pupil as well, as they don't have to listen to their parents grumbling about the noise, so the advantages work both ways.
There are also advantages and disadvantages in playing an electric violin. When played in a pop band, it's general that all the instruments are electric and don't make any noise themselves, and all sound comes out of the PA system. If you are playing a conventional violin where everybody else is playing electric instruments, it can become very confusing, as you can hear your own sound from close by i.e. under your chin, and also here own music coming out of the loudspeakers, but everybody else's music is coming out of the loudspeakers only. In this situation, electric violin is a great advantage. It also has the electric sound that blends better with electric guitars, electric keyboards and so on. If playing an electric instrument when everybody else in the band is playing acoustic instrument, as sometimes happens in a jazz band or a barn dance band, then it can become confusing once again, because you're hearing sound from other instruments directly from the instruments i.e. way you would expect them to come from and is what happens when you're playing in a string quartet for example, but your instrument isn't making any noise; all the sounds coming from the speakers, which can be in quite a different location, and of course there are time delays in sound travelling across a room from the distant loudspeaker which causes further chaos. The ultimate in confusion is the ceilidh band where there is an electric bass guitar and electric violin, both of which can only be heard through the systems loudspeakers, but there is an acoustic guitar and perhaps a flute or whistle, where most of the sound that you can hear onstage comes from their instruments. The brain can't cope with this, and you get a situation where you can hear your violin and the bass guitar but not the other instruments, then after a few moments you focus on the other instruments which onstage with you and the sound of your violin and the bass guitar disappears. So really all instruments have to be acoustic, or all instruments have to be electric to be really successful. An example of this is a jazz band I heard a couple of years ago, where the superb violinist played on electric violin, the bass player was playing an electric double bass i.e. an instrument without any sandbox, and the keyboard player was playing an electric keyboard, so no sound was coming out of the instrument itself. All sound came out of the loudspeakers so there were no time delay issues for the musicians.
By now I've digressed rather far from the orchestral instruments that I was talking about earlier, so it's about time I get on track and stop rambling. Let's talk about how we get a noise out of this box of wood. The usual way of playing it is with the bow, which has changed considerably since Bach's day. Back then, it was a curved bow which enabled string players to directly control the tension of the bow hairs, so that they could play one, 2, 3 or 4 strings simultaneously, and make this adjustment while playing the instrument. The high arch of the bow enables this to be done, so that sustained chords on all 4 strings can be played. There's a lever mechanism at the end where the modern bow has screwed adjusted not, to adjust the tension of the bow hair.