‘A rough guide to viola strings’ by William Castle

To make sense of the multitude of strings being produced, we can divide them into categories according to the type of material used to make the central part of the string, the core.

There are three core types – gut, synthetic, and steel.

  • Gut strings give the warmest sound, and a wide range of colours. Their response under the bow is relatively slow, and they don’t stay in tune for very long, the gut being sensitive to temperature and humidity.
  • Steel cored strings are bright, they have a quick response, they stay in tune, but they can be harsh, edgy and lacking in warmth.
  • Synthetic core strings fall between gut and steel. They can have tonal characteristics nearly as warm as gut, but some are nearly as bright as steel strings. They are stable so they stay in tune, their response is quicker than gut and sometimes nearly as quick as steel.

Because of the instability of gut strings, their short life and expense, few people nowadays use them, though Pirastro do produce a string with a stabilised gut core, under the brand name Passione, which reputedly is nearly as stable as a synthetic core. Since the advent of synthetic strings, steel strings have become less popular because synthetic strings have many of the the good features of steel strings but with better tonal qualities. But on some violas which are naturally mellow, steel strings are still an option.

However, the material used to make the core is not the whole story; the way the core is constructed and the methods and materials used to make the windings also have a great influence on the tonal qualities, so each individual make of string has its own individual qualities.

 A simple and practical start- what I usually do

When I am putting strings on violas I have made, I choose strings that I think work best on that instrument, no matter what they cost. In practice I usually use Evah Pirazzi, a synthetic cored string made by the Pirastro company.  These strings are on the bright side for a synthetic string, they project well, have a quick response, but crucially they have a wide range of tone colour.

On some violas, those which are very happy in their own skin, easily producing a projecting and open sound, I sometimes use Obligato strings, also made by Pirastro. Obligato strings are the synthetic string that are nearest in tone quality to gut, and for a relaxed sound that just allows the instrument to breathe they are a good choice. However, on some instruments and for some tastes, Obligato A strings can be a bit too rounded and without enough edge. In this case I use an Evah Pirazzi or a Larson A, which usually blend with the Obligato.

On small violas, and on other violas which need a bit of a push, Evah Pirazzi are a good starting point, in  part because of their higher tension. With an instrument with a short string length, strings that are intrinsically of a higher tension often work well.

To understand how this works, imagine  that you have a bigger viola  but want to see how it feels with a shorter string length, so you use a guitar capo to shorten the string length, putting it, let’s say, where you put your first finger in first position. To play it in pitch, you then need to tune your strings down a tone, which obviously means that the strings are slacker. So just because you use strings that are intrinsically high tension, on an instrument with a short string length, that does not necessarily mean you are putting more tension on the instrument.

The other string I sometimes use is Vision Solo from Thomastik. These are a higher tension soloistic type of string, where if you put the effort in, you get more out. However with violas that have a short string length [less than 37 cm] the string is at a lower tension compared with  a viola with a long string length, so the soloistic nature is toned down.

What about your viola?

Let’s assume you want to get the best sound out of your instrument, combined with ease of playing and regardless of cost. Unless you know you want gut or steel strings, try doing what I do, starting with Evah Pirazzi and possibly moving on from there. However, you still may have problems with one or more strings.

A  common problem with violas is woolly or pathetic C strings, which often feel they are running away from the bow, so you need to use greater bow pressure to create and control the sound when  moving from the G to the C string. In this case a string of greater thickness or tension can help. So in the old days I often used to use a Dominant stark or nowadays you might choose Spirocore, both of which are  heavy and high tension. If Obligato work on the other strings, you could combine these with an Evah Pirazzi  or a Vision Solo C. Once you have a thicker or higher tension string such as Spirocore on the C, you might find that the G seems weak in comparison, and be tempted to try a similar string on the G string, and then perhaps the same on the D. This may work, but be aware that it may restrict the sound of the whole viola because of the increased tension on the instrument.

Another common problem with violas is a harsh A string, in which case you need to go for something softer.So if you have a steel A string, try progressively, Evah Pirazzi, Larsen, Obligato, and Passione, or choose the soft version of the string you are using. Go in the opposite direction if you want more power or edge to the A.

The soft, medium and hard versions of the same string represent different thicknesses and tensions of the same string. On most violas I would start by trying the medium, which are most easily available,  but on a viola with a long string length [over 37cm or 14 ½ “] a thinner lower tension string may be better, whereas a short string length may work better with a thicker or higher tension string.

Other strings worth considering are Larsen, which are nice quality though perhaps less varied in tone colour and dynamism than Evah Pirazzi, perhaps Dominants if you want low tension strings, or Jargars, particularly for A strings; and I am sure there are other good strings I haven’t tried.

A cheaper solution

If the price of strings is a factor, there are cheaper strings available, mostly steel cored. On violas with a long string length Prim works for some, and on violins I have used Helicore which have surprisingly good tonal qualities combined with the rapid response typical of steel strings. For a cheap synthetic string Zyex has good tonal qualities and projection, though again my experience with them is only on violins.


Having said all this, your viola may work best with completely different strings. You may also like a different type of sound, viola sound varying tremendously between musicians and instruments.

Also, as an instrument maker and one-time repairer, I must mention that the position and tension of the soundpost, the cut of the bridge, and its height, which is governed by the angle the fingerboard makes with the belly, also make a major difference to the sound of your viola. It may be the case that the best way to improve the sound of your viola [short of changing the person who plays it!]  would be to get it checked by a violin maker who is interested in sound, before messing around with strings. However, the right choice of strings can make all the difference, whether the instrument has an indifferent or an excellent set up.

William Castle

29 April 2015