People are picky aren’t they? Just walk into a supermarket and look at all the different types of milk you can buy. Or how things should be done so that they are ‘just so’. Take a steak for example. If you eat meat you will probably have your favourite beef steak cut. Possibly even the breed of cow and/or if it has been dry aged or not and for how long! What’s more we like it cooked to 6 different temperatures:
All this choice to get that perfect flavour. Damn, some people are hard to please. Well, it turns out us cellists are just as fussy when it comes to strings.
Actually, we’re probably worse.
There are over 10 different string manufacturers commonly available, each with a huge range to choose from. Pirastro for instance sells 20 sub-brands of cello strings, some with different material options. And pretty much all come in 3 different tensions. So that’s AT LEAST 60 different types of cello strings to choose from. From one manufacturer alone!!
Here at Rostanvo we agree that the types of materials used is an important factor. Read our article on the subject.
But what about tension?
Definition of tension
The theory goes you should opt for a tension that suits best your particular instrument and playing style (a bit like choosing that perfect steak). Most of us will be unsure which one to specifically go for, so we’ll choose ‘medium’. It sounds comforting in a world of extremes. Popular. Safe.
There is a tiny bit of truth to the idea that different tensions behave differently depending on the playing style.
Surprisingly, tension is easy to measure on a string. Either by using a monochord with weights at the end. Or by cutting the vibrating length of the string (ie between bridge and nut) weighing it and measuring its length). While it can provide us with some information on how the string will behave, it actually says little about how the string will actually sound.
The key variable tension can give us is an indication of is the string's impedance. Put simply, impedance tells us how much energy the string can carry and relay onto the instrument. The higher the tension, the larger impedance, resulting in a louder sound.
But it does not tell us anything about the string's frequency output. Ie the distribution and combination of harmonic and inharmonic frequencies which give the instrument its quality or timbre of sound.
A cello’s changing shape with strings
Admittedly, the cello body's shape does change slightly when there are no strings attached to when strings are tuned onto the instrument. But the impact to the shape between high and medium tension strings is too slight to have any noticeable change. If you don't believe us, there's a very simple experiment you can perform to prove this to yourselves. Read our article on "The cello string tension test you have to try" for instructions.
But tension can still be a useful measure from a player's perspective. High tension strings, because of the greater levels of impedance, need more energy given by the player in order make them sound. They are more power hungry and can sound louder. But they are also harder to control (an issue on the C and G strings), especially at lower volumes. No surprise then that "soloist" strings tend to have higher tensions (as marginally more skill is required to play them). Another issue is they can amplify wolf tones, unsurprisingly because the strings are louder.
Higher tension strings however have one key advantage aside from sounding louder. They maintain their intonation more easily at a range of pressure levels. Take the C string for instance. Try playing the same note with light and then heavy bow pressures. The pitch should rise. This is particularly pronounced on low tension strings while the higher tension equivalent will maintain its pitch much better, mainly because the increased weight reduces the elasticity of the string.
Putting this all aside, let’s put this into perspective and not forget that if the type of sound you are getting from your string is naturally more to your liking, the playing experience ends up being easier and thus more enjoyable. The quality of sound you get is the most important thing. Even with low tension strings intonation movement you can encounter can be adjusted with your technique to an extent.
So to conclude, be wary of focusing too much on string tension. It is the easiest piece of "technical information" you can get on strings. So easy you can calculate it yourself! But sound wise, there are other factors which merit more thought.