The wide world of strings!
From screaming electric guitars to the most delicate of violins, string instruments are among the most-loved sounds in the .
So, how exactly do stringed instruments work?
Actually, a lot like !
Like drums, string instruments have two essential parts: the material held in tension (which will create the instrument’s sound), and the frame (which sustains the tension, and can also modify the sound created). With drums, the material-in-tension was a membrane – with strings, that material-in-tension is, well, a string!
When a string in tension is moved from its resting point, its tendency is to ‘want’ to snap back to its original, resting position. In doing so, it will have a tendency to go too far to one side, then too far to the other, moving closer and closer to its resting point, until the motion stops. To picture this phenomenon more easily, imagine a hammock. You’re lying in a hammock that’s at rest – no movement. Then, someone gives you a big push to one side! For the next minute or two, you’ll swing back and forth, until you stop again at the resting position.
That’s exactly how a string instrument works! The only difference is that the high tension in, say, a guitar string results in much faster vibrations. In string instruments, that moving-back-and-forth happens very quickly; we see it as the string vibrating in a blur. The back-and-forth motion is also what causes the vibrations in the air that we hear as the instrument’s sound!
Here’s how guitar strings look in slow-motion, to help us picture what’s going on:
A hammock moves back and forth maybe once every two seconds – a frequency of 1/2 cycles per second, or 0.5 Hz. Recall from our earlier discussion that the human ear experiences vibrations as low as about 15 Hz as sound. If we could hear just a bit lower, we would hear the swinging motion of the hammock! Not the wood creaking, not the fabric rubbing, but the actual vibrating motion of the hammock. Cool perspective!
So next time someone says, “Dude you’re lazy, you’ve been in that hammock for ages,” you can respond with, “Dude, I’m playing sub-audible music on a giant string instrument.” Nice.
So then, the faster a string is vibrating, the higher the pitch we hear. A few things determine the frequency of vibration: material of string, width of string, tension in string, and effective length of string. The denser the material, the slower that material will vibrate – denser material, lower pitch. Thicker strings of a given material also vibrate slower, and so create a slower pitch – thicker string, lower pitch. The more tension in a string, the faster it will return to the resting state, creating faster vibrations – more tension, higher pitch. The shorter a string is, the less string you have for stretching, so the less it will stretch and faster it will vibrate – shorter string, higher pitch.
So, now that we have a brief grasp of how string instruments work – let’s look at some examples!
Our first instruments are ‘single-note strings,’ meaning that each string has a particular note to play. Harps are perhaps the most well-known examples of single-note strings – and one of the oldest!
Conjuring images of cherub angels and heavenly concords, harps can be found just about everywhere. In a harp, single-note strings are suspended between opposite sides of a single frame.
Here are a few of the more unique-looking harps from around the world:
Other single-note string instruments use a backboard or body to hold strings in tension. These instruments create sounds noticeably distinct from the sounds harps make. Oftentimes, the backboards or bodies are shaped as resonating chambers that effect the sounds being created. The method of ‘attack,’ or the way strings are engaged, can also effect the sound produced. The piano and dulcimer for example are both hammered. The piano is hammered with felt over wood, and the dulcimer is hammered with metal mallets. The harpsichord on the other hand is plucked much like a guitar – only with feather quills (or modern equivalents) instead of fingers.
The sounds created by these diverse constructions and methods of attack are remarkably distinct:
A Debussy piece played on a concert harp:
A Chopin piece played on a grand piano:
A performance on a hammered dulcimer:
An arrangement of a Tool song, Lateralus, for an ensemble of Japanese Koto instruments:
Multi-note string instruments have the capacity to play different notes on each string. Usually, this is achieved by changing the effective length of a string, by clamping the string at a particular point – think of our standard guitar being clamped at different points along the guitar’s neck.
The history of the lutes, mandolins, guitars, citharas, balalaikas, cavaquinos and banjos of the world are quite involved. The oldest examples we’ve found have been excavated from ancient ruins of what were once Babylon and Sumeria. The ‘tanbur’ as it’s called is a 4-string instrument, in which each string can be clamped by hand along a wooden neck. From this ancient 4 string Tanbur, it seems each culture gave it’s own style of construction to suit the aesthetics of the culture, creating a wide variety of ‘multi note string’ instruments with a wide variety of sound.
What determines the quality of sound with these instruments is an array of factors including: material, shape and size of the resonating chamber, length and width of the neck, material of the strings, shape of the sound hole(s) and the pitch that each string is tuned to.
Classical acoustic guitars are generally strung with nylon strings, and plucked with finger nails:
Folk and rock acoustic guitars generally use steel strings and a plastic or fiberglass pick.
Quite a different sound, right? Now, take the banjo – an instrument which is essentially similar in construction, but which uses a metal body and metal picks.
On the softer side of the necked string group is the mandolin. The mandolin utilizes nylon strings and a rounded wooden body.
The Mighty Viols
A family which must be mentioned in any discussion of string instruments is the viol family. (think violin, viola, cello and double bass).
Centuries of evolution and multiple cultures intermingling in a cosmopolitan way gave birth to a revolutionary piece of equipment for the string family which we call the ‘bow’.
The bow allows for a viol player to sustain a note and use expressive techniques on that note like crescendo, diminuendo and vibrato. Sustained notes created a rich opportunity to blend, combine, and harmonize multiple instruments. Quite simply: it’s easier to musically organize notes that last many seconds, as opposed to plucked notes!
Because of this, the viols became the backbone of the symphony orchestra, which was one of the first multi-national musical ensembles with a shared tuning, nomenclature and repertoire. With viol backbones, orchestras could incorporate vastly different instruments, from diverse cultures and countries. In a very substantive way, the viol family can be considered musical ambassadors of unity and peace!
One of my favorite examples of the amazing synergy which can be created by an ensemble of viols is Samuel Barber’s Adagio for strings. It is a testament to the intrinsic beauty in the sound of a vibrating string and the amazing harmony we can create when we come together.
Do you have a favorite string instrument to listen to? Is there a string instrument you play, or used to play? Share your experience with this beloved instrument family, in the comments below!
Stay harmonious through this holiday season! Next week, we celebrate the season of twinkle lights and gift-giving with a musical instrument that seems to thematically find it’s home in December – the Bells!