Northern Renaissance Instruments
6 Needham Avenue, Chorlton-cum-Hardy, Manchester M21 8AA, U.K.
Phone & Fax. +44 (0) 161 881 8134 ; proprietor: Dr. Ephraim Segerman [USA
e-mail: firstname.lastname@example.org ; on internet: http://www.nrinst.co.uk
PROCESSED POLYMER STRINGS
Prices valid 2009
The higher-pitched strings on guitars and lutes are usually made of polymer monofilament, and the lower-pitched strings are made of metal wound on polymer floss. Some brands of bowed-instrument strings have lower strings made of metal wound on polymer floss, and some double bass strings are made of metal wound on monofilament The floss polymer is almost always nylon, and the monofilament polymer is usually nylon, but it sometimes is polyester, kevlar or polyvinylidene fluoride (PVF).
We can hand-process polymer monofilaments in various ways similar to how we process gut. Processed monofilament strings give new choices in tone quality for a variety of instruments. In the bass range, they offer a warm gentle sound like that of gut, as opposed to the more projecting metallic sound of metal-wound strings. This avoids the disadvantages of gut, which are mainly that of expense and of tuning sensitivity from humidity changes. The disadvantages compared to metal-wound strings are that the overall diameter is greater (requiring larger holes in bridges and pegs, and larger channels on the nut), and less projection. In higher ranges, these strings offer a brighter sounding alternative to simple monofilament strings. Because of greater strength of the material, string constructions with higher twist than gut for the pitch and string length are often possible. There are some bowed gut-strung instruments that are played at a higher pitch than appropriate, making the gut 1st to break too quickly, so some players use a 2-strand nylon rope for the 1st when not playing in public.
The various types of hand-processed polymer strings we make are:
three-strand catline rope
two-strand catline rope
monofilament wound on monofilament
The catlines in three and two strands can be made with different amounts of twist, with lower twist avoiding the breaking limit of thinner ones and maximum twist to give the brightest sound for the thicker ones.
We have ample stocks of quite a few diameters of nylon monofilament, but only a few diameters in polyester monofilament, and small quantities of PVF in various diameters. Stocks will be expanded only if there is sufficient demand.
When we produce a processed polymer string, we measure its ED (Equivalent Diameter). That is the diameter of a fictitious plain monofilament string of the same material that has the same weight per unit length as the actual string, so that they would produce the same tension when tuned to the same pitch. We also use the term 'gut ED' where the comparison is with a plain gut string that will give the same tension. By keeping the gut ED the same when replacing a string of one type with one of a different type, one can hear the effect of string type alone, without the influence of tension. Polyester has the same density as gut, so the polyester ED is the same as the gut ED. The nylon ED of a string is 12% greater than the gut ED because nylon is less dense than gut, so a greater diameter is needed for the same weight. The PVF ED is 12% less than the gut ED because PVF has a higher density.
The amount of brightness in the sound of a string depends on its elasticity. Stiffness reduces brightness by creating inharmonicity in the sound. Inharmonicity makes the higher harmonics out of tune with multiples of the fundamental. A small amount of inharmonicity gives a different character of the sound, which is considered attractive in the higher ranges of the piano and of the dulcimer. More inharmonicity reduces the strength of the higher harmonics and makes more disappear. Brightness depends on hearing the higher harmonics.
With the same ED, high-twist monofilament sounds brighter than plain monofilament, a catline rope sounds brighter than a high-twist monofilament. Nylon wound on nylon produces a different kind of brightness than the others, and depends on the relative diameters of the core and the winding.
Inharmonicity increases with increased diameter and with lower pitch. Thus brightness naturally decreases as one goes to lower strings on an instrument, and one usually changes to a more elastic type of string to reduce this effect. Winding with metal is a very effective way of doing this since only the core contributes to the inharmonicity (but the metal winding, acting as a spring, can absorb some of the vibration energy). Such strings are quite satisfactory for the 4th to 6th strings of the guitar. The 3rd string is usually plain monofilament, and sounds a bit dull compared to the 2nd and 4th strings. It can't be wound with the usual metal because its required weight per unit length is so low that with a core thick enough not to break, the metal would be too thin to handle. Winding with aluminium lets it be thick enough, but the aluminium winding absorbs vibration more, thus reducing sustain. A higher density of monofilament decreases inharmonicity, so the 3rd string brightness can be improved by using polyester, and more so by using PVF. The inharmonicity can also be decreased using nylon with high-twist monofilament or with catline rope. Another possibility is nylon wound on nylon, as is used on the koto and other Eastern instruments, as well as some brands of classical guitar strings. If a guitar construction inhibits the brightness of the 2nd or even 1st strings, these can be improved by using high-twist monofilament or catline rope. Such strings have been successfully used for the treble strings of some bowed instruments.
With metal-wound basses, the lute has the same problem with its 4th course as the guitar has with its 3rd, and the solutions are the same. Many lute players find that metal-wound basses are two brilliant and have too much sustain. They sometimes use very old bass strings that have become dull by dirt and skin particles getting in with the windings, and sometimes they dull new strings by rubbing beeswax into the windings. They could get much closer to the original gut bass sounds if they want to by using catline roped nylon.
We would welcome experimenters to try our processed polymer monofilament strings. Because of limits in the diameters we have in stock, we are not attempting to compete in the plain monofilament market. For the moment, we are applying the prices for nylon to all of the polymers. These prices are:
Prices for Nylon Equivalent Diameter (ED) Ranges