Nak Tarhu Strings

Cello Strings:

A 5-string cello set is used, tuned an octave above normal cello pitch. Cello strings are the choice of most Cretan lyra players, as well as for some contemporary Indian sarangi players. Having been developed over centuries for the extremely rigorous demands of the cello repertoire, these strings respond well across a huge variety of techniques and musical requirements.

Horse-hair strings:

Strings made from horsehair have been used by various cultures over the centuries, with the use of natural hair often being replaced by nylon in recent years.  The individual strands of such strings are all completely straight and parallel to each other, as seen in the horse-hair used in a musical bow – there is no twisting or wrapping involved. Instruments using this type of string include the Morin Khuur from Mongolia, the Jouhikko from Finland and the Rebab from Egypt.

Soon after the lyra tarhu was made for Ross Daly he re-strung it, changing from cello strings to horse-hair style strings that he made out of nylon. When the nak tarhu was created, it likewise used horse-hair style strings. Unfortunately using horse-hair style throughout on a 5-string instrument meant that the bass string especially became very thick (nearly 4mm in diameter) and was consequently limited in the range of sounds and techniques it was capable of supporting.

Metal UDMS strings:

Horse-hair and nylon are at one end of the spectrum of the materials that can be used for “horse-hair style” strings, with fine metal wire at the other end. However, when it comes to using something like fine tungsten wire for the fibres instead of horse-hair or nylon, the name “horse-hair style” becomes a bit questionable. These strings can also be called Uni-Directional Multi-Strand strings (UDMS), defining them by their structure rather than by the material used.

Very fine metal wire in a UDMS string behaves in a similar way to horse-hair – the individual strands combine together so far as string weight is concerned, but they remain separate so far as string stiffness is concerned. If very fine tungsten is used, the stiffness remains low, but tungsten’s extreme weight makes the string heavy with a very small overall diameter when compared to other string materials. This radical change in string diameter has a proportionately radical effect on the sounds the bass strings are capable of making.

At the current stage of experiments with this type of string (July 2019), indications are that the best results for a 5 string nak tarhu set would come from: strings 5 and 4 – tungsten 0.08mm; strings 3 and 2 – brass 0.1mm; string 1 – steel 0.1mm. String #2 may also be better in steel rather than brass. The graduation in metal types goes from heaviest (tungsten) to lightest (steel). This helps in not having bass strings too thick or treble strings too thin (steel is less than half the weight of tungsten and is therefore thicker for the same pitch).

Tungsten is available in such small diameters that working with the wire can be extremely difficult – at the thinnest end of the range, tungsten wire is so fine that it can only be seen by the naked eye in very particular lights. 0.08mm was therefore chosen as the finest that is practicable for string-making purposes. Brass and steel are not readily available thinner than 0.1mm, so that was the diameter chosen for those metals.

Metal UDMS strings present the player with a wider tone-colour palette and greater sensitivity than either of the two other string types. The sound is more multi-dimensional than with cello strings and more even than with nylon UDMS (the entire range of the instrument becomes fully usable). Hopefully as the use of these new strings develops and is further refined, the nak tarhu will be able to realise more of the potential contained within its design. If anyone is interested to work with these strings, the wires mentioned above are available from:

Tungsten: http://midwesttungsten.com/

Brass: https://dglisuo.en.alibaba.com/search/product?SearchText=EDM%20wire

Steel: https://stainless-wire.us/hard-wire-piano-wire/coils-o-0-10-to-0-80mm

NB Tungsten wire is rather expensive - as of 2019, $190 usd for 500 mtrs. While 500 mtrs can make quite a few strings, it still works out to be over $4000 per kg………compared to brass wire which currently costs $15 per kilo (the brass wire mentioned above is used as a consumable in Electrical Discharge Machines and has to be cheap to be viable for this application). While tungsten has very particular qualities, it might be worth considering buying a spool of brass wire first, see if you like the idea and only buy tungsten and steel if you want to proceed further.

When making UDMS strings, it is not necessary to buy a whole range of gauges of each material. UDMS strings are based on a different concept to single strand strings, where as the pitch goes down the diameter of the single strand has to increase. In UDMS strings, one keeps the diameter of the individual strands the same and instead increases the number of strands to produce a lower pitch. Increasing the strand thickness as the pitch goes down does reduce the number of strands required for each string, but at the expense of sound quality - as strand thickness increases, the amount of extraneous noise generated by the string also increases. It is better to select the finest strand that is workable and then use that same strand diameter in all strings made of that material.

Calculations for UDMS Strings (added October 2019):

A four stage process is required to calculate the number of strands required to make a UDMS string of the desired string tension/pitch.

Stage 1: The charts below provide the diameter (in millimetes) of a single, very thick strand of Nylon, Steel, Brass or Tungsten. These diameters indicate the correct amount of string material required for a string to be tuned to the tension/pitch indicated. These calculations were done with the invaluable help of the string calculator created by Arto Wikla (which can be accessed here: https://www.cs.helsinki.fi/u/wikla/StringCalc.html). Arto very kindly adapted his calculator to include Tungsten, making it possible to complete these calculations. The calculator requires Java to be enabled, so open it either in Microsoft Edge or else on your mobile phone. If you are happy to work within the string length/material/tension parameters listed in the charts below, you won’t need to use the calculator - this stage has already been done for you.

Stage 2: The cross sectional area has to be determined for each of the string diameters that are required. Eg, if one needs a steel string tuned to A at 9kgs, from the charts below see that the diameter is 0.47mm . Using πr² (r being radius) find the cross sectional area - π(0.47/2)² = 0.173mm²

Stage 3: Calculate the cross sectional area of the fine wire you have chosen as the raw material for your string, again using πr² . If you are using the sizes I suggested above, Steel 0.10mm = 0.0079mm², Brass 0.10mm = 0.0079mm² and Tungsten 0.076mm = 0.0046mm².

Stage 4: The number of individual strands of the particular wire you have chosen needs to be calculated. Divide the cross sectional area in Stage 2 by the cross sectional area in Stage 3. This will give you how many strands of your chosen wire are required to make up the the total cross sectional area selected from the charts below. Eg, again, a steel string tuned to A at 9kgs, diameter is 0.47mm, cross sectional area is 0.173mm². Divide by area of 0.1mm strand 0.0079mm² = 21.9

So, to create an A string at 9kgs tension, made from 0.1mm steel strands, 22 strands will be required.

NB: a note on String Tension: When a Cretan lyra at 290mm vibrating string-length uses cello strings G, D and A, the resulting string tensions (averaged over 10 different brands of cello strings) are G: 9.5kg, D: 9.5kg, A: 12.5kg. The lyra strings created specifically by the D’Addario company are lower tension than this - G: 5.5kg, D: 8kg, A: 11.5kg. I am not a lyra player nor a nak tarhu player, so I won’t try and guess the best string tension - I just present below a range that should cover most options.